| Message ID | 20190131030812.GA2174@jordon-HP-15-Notebook-PC (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Use vm_insert_range and vm_insert_range_buggy | expand |
On Thu, Jan 31, 2019 at 08:38:12AM +0530, Souptick Joarder wrote: > Previouly drivers have their own way of mapping range of > kernel pages/memory into user vma and this was done by > invoking vm_insert_page() within a loop. > > As this pattern is common across different drivers, it can > be generalized by creating new functions and use it across > the drivers. > > vm_insert_range() is the API which could be used to mapped > kernel memory/pages in drivers which has considered vm_pgoff > > vm_insert_range_buggy() is the API which could be used to map > range of kernel memory/pages in drivers which has not considered > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > We _could_ then at a later "fix" these drivers which are using > vm_insert_range_buggy() to behave according to the normal vm_pgoff > offsetting simply by removing the _buggy suffix on the function > name and if that causes regressions, it gives us an easy way to revert. > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > Suggested-by: Russell King <linux@armlinux.org.uk> > Suggested-by: Matthew Wilcox <willy@infradead.org> > --- > include/linux/mm.h | 4 +++ > mm/memory.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > mm/nommu.c | 14 ++++++++++ > 3 files changed, 99 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 80bb640..25752b0 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2565,6 +2565,10 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, > int remap_pfn_range(struct vm_area_struct *, unsigned long addr, > unsigned long pfn, unsigned long size, pgprot_t); > int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *); > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num); > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > + unsigned long num); > vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, > unsigned long pfn); > vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, > diff --git a/mm/memory.c b/mm/memory.c > index e11ca9d..0a4bf57 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1520,6 +1520,87 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > } > EXPORT_SYMBOL(vm_insert_page); > > +/** > + * __vm_insert_range - insert range of kernel pages into user vma > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * @offset: user's requested vm_pgoff > + * > + * This allows drivers to insert range of kernel pages they've allocated > + * into a user vma. > + * > + * If we fail to insert any page into the vma, the function will return > + * immediately leaving any previously inserted pages present. Callers > + * from the mmap handler may immediately return the error as their caller > + * will destroy the vma, removing any successfully inserted pages. Other > + * callers should make their own arrangements for calling unmap_region(). > + * > + * Context: Process context. > + * Return: 0 on success and error code otherwise. > + */ > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num, unsigned long offset) > +{ > + unsigned long count = vma_pages(vma); > + unsigned long uaddr = vma->vm_start; > + int ret, i; > + > + /* Fail if the user requested offset is beyond the end of the object */ > + if (offset > num) > + return -ENXIO; > + > + /* Fail if the user requested size exceeds available object size */ > + if (count > num - offset) > + return -ENXIO; > + > + for (i = 0; i < count; i++) { > + ret = vm_insert_page(vma, uaddr, pages[offset + i]); > + if (ret < 0) > + return ret; > + uaddr += PAGE_SIZE; > + } > + > + return 0; > +} > + > +/** > + * vm_insert_range - insert range of kernel pages starts with non zero offset > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * > + * Maps an object consisting of `num' `pages', catering for the user's > + * requested vm_pgoff > + * The elaborate description you've added to __vm_insert_range() is better put here, as this is the "public" function. > + * Context: Process context. Called by mmap handlers. > + * Return: 0 on success and error code otherwise. > + */ > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) > +{ > + return __vm_insert_range(vma, pages, num, vma->vm_pgoff); > +} > +EXPORT_SYMBOL(vm_insert_range); > + > +/** > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * > + * Maps a set of pages, always starting at page[0] Here I'd add something like: Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to 0. This function is intended for the drivers that did not consider @vm_pgoff. > vm_insert_range_buggy() is the API which could be used to map > range of kernel memory/pages in drivers which has not considered > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > + * > + * Context: Process context. Called by mmap handlers. > + * Return: 0 on success and error code otherwise. > + */ > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) > +{ > + return __vm_insert_range(vma, pages, num, 0); > +} > +EXPORT_SYMBOL(vm_insert_range_buggy); > + > static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, > pfn_t pfn, pgprot_t prot, bool mkwrite) > { > diff --git a/mm/nommu.c b/mm/nommu.c > index 749276b..21d101e 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -473,6 +473,20 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > } > EXPORT_SYMBOL(vm_insert_page); > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) > +{ > + return -EINVAL; > +} > +EXPORT_SYMBOL(vm_insert_range); > + > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) > +{ > + return -EINVAL; > +} > +EXPORT_SYMBOL(vm_insert_range_buggy); > + > /* > * sys_brk() for the most part doesn't need the global kernel > * lock, except when an application is doing something nasty > -- > 1.9.1 >
On Thu, Jan 31, 2019 at 2:09 PM Mike Rapoport <rppt@linux.ibm.com> wrote: > > On Thu, Jan 31, 2019 at 08:38:12AM +0530, Souptick Joarder wrote: > > Previouly drivers have their own way of mapping range of > > kernel pages/memory into user vma and this was done by > > invoking vm_insert_page() within a loop. > > > > As this pattern is common across different drivers, it can > > be generalized by creating new functions and use it across > > the drivers. > > > > vm_insert_range() is the API which could be used to mapped > > kernel memory/pages in drivers which has considered vm_pgoff > > > > vm_insert_range_buggy() is the API which could be used to map > > range of kernel memory/pages in drivers which has not considered > > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > > > We _could_ then at a later "fix" these drivers which are using > > vm_insert_range_buggy() to behave according to the normal vm_pgoff > > offsetting simply by removing the _buggy suffix on the function > > name and if that causes regressions, it gives us an easy way to revert. > > > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > > Suggested-by: Russell King <linux@armlinux.org.uk> > > Suggested-by: Matthew Wilcox <willy@infradead.org> > > --- > > include/linux/mm.h | 4 +++ > > mm/memory.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > mm/nommu.c | 14 ++++++++++ > > 3 files changed, 99 insertions(+) > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index 80bb640..25752b0 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -2565,6 +2565,10 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, > > int remap_pfn_range(struct vm_area_struct *, unsigned long addr, > > unsigned long pfn, unsigned long size, pgprot_t); > > int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *); > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num); > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num); > > vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, > > unsigned long pfn); > > vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, > > diff --git a/mm/memory.c b/mm/memory.c > > index e11ca9d..0a4bf57 100644 > > --- a/mm/memory.c > > +++ b/mm/memory.c > > @@ -1520,6 +1520,87 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > > } > > EXPORT_SYMBOL(vm_insert_page); > > > > +/** > > + * __vm_insert_range - insert range of kernel pages into user vma > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * @offset: user's requested vm_pgoff > > + * > > + * This allows drivers to insert range of kernel pages they've allocated > > + * into a user vma. > > + * > > + * If we fail to insert any page into the vma, the function will return > > + * immediately leaving any previously inserted pages present. Callers > > + * from the mmap handler may immediately return the error as their caller > > + * will destroy the vma, removing any successfully inserted pages. Other > > + * callers should make their own arrangements for calling unmap_region(). > > + * > > + * Context: Process context. > > + * Return: 0 on success and error code otherwise. > > + */ > > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num, unsigned long offset) > > +{ > > + unsigned long count = vma_pages(vma); > > + unsigned long uaddr = vma->vm_start; > > + int ret, i; > > + > > + /* Fail if the user requested offset is beyond the end of the object */ > > + if (offset > num) > > + return -ENXIO; > > + > > + /* Fail if the user requested size exceeds available object size */ > > + if (count > num - offset) > > + return -ENXIO; > > + > > + for (i = 0; i < count; i++) { > > + ret = vm_insert_page(vma, uaddr, pages[offset + i]); > > + if (ret < 0) > > + return ret; > > + uaddr += PAGE_SIZE; > > + } > > + > > + return 0; > > +} > > + > > +/** > > + * vm_insert_range - insert range of kernel pages starts with non zero offset > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * > > + * Maps an object consisting of `num' `pages', catering for the user's > > + * requested vm_pgoff > > + * > > The elaborate description you've added to __vm_insert_range() is better put > here, as this is the "public" function. Ok, will add it in v3. Which means __vm_insert_range() still needs a short description ? > > > + * Context: Process context. Called by mmap handlers. > > + * Return: 0 on success and error code otherwise. > > + */ > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > +{ > > + return __vm_insert_range(vma, pages, num, vma->vm_pgoff); > > +} > > +EXPORT_SYMBOL(vm_insert_range); > > + > > +/** > > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * > > + * Maps a set of pages, always starting at page[0] > > Here I'd add something like: > > Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to > 0. This function is intended for the drivers that did not consider > @vm_pgoff. Ok. > > > vm_insert_range_buggy() is the API which could be used to map > > range of kernel memory/pages in drivers which has not considered > > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > > + * > > + * Context: Process context. Called by mmap handlers. > > + * Return: 0 on success and error code otherwise. > > + */ > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > +{ > > + return __vm_insert_range(vma, pages, num, 0); > > +} > > +EXPORT_SYMBOL(vm_insert_range_buggy); > > + > > static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, > > pfn_t pfn, pgprot_t prot, bool mkwrite) > > { > > diff --git a/mm/nommu.c b/mm/nommu.c > > index 749276b..21d101e 100644 > > --- a/mm/nommu.c > > +++ b/mm/nommu.c > > @@ -473,6 +473,20 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > > } > > EXPORT_SYMBOL(vm_insert_page); > > > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > +{ > > + return -EINVAL; > > +} > > +EXPORT_SYMBOL(vm_insert_range); > > + > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > +{ > > + return -EINVAL; > > +} > > +EXPORT_SYMBOL(vm_insert_range_buggy); > > + > > /* > > * sys_brk() for the most part doesn't need the global kernel > > * lock, except when an application is doing something nasty > > -- > > 1.9.1 > > > > -- > Sincerely yours, > Mike. >
On Thu, Jan 31, 2019 at 03:43:39PM +0530, Souptick Joarder wrote: > On Thu, Jan 31, 2019 at 2:09 PM Mike Rapoport <rppt@linux.ibm.com> wrote: > > > > On Thu, Jan 31, 2019 at 08:38:12AM +0530, Souptick Joarder wrote: > > > Previouly drivers have their own way of mapping range of > > > kernel pages/memory into user vma and this was done by > > > invoking vm_insert_page() within a loop. > > > > > > As this pattern is common across different drivers, it can > > > be generalized by creating new functions and use it across > > > the drivers. > > > > > > vm_insert_range() is the API which could be used to mapped > > > kernel memory/pages in drivers which has considered vm_pgoff > > > > > > vm_insert_range_buggy() is the API which could be used to map > > > range of kernel memory/pages in drivers which has not considered > > > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > > > > > We _could_ then at a later "fix" these drivers which are using > > > vm_insert_range_buggy() to behave according to the normal vm_pgoff > > > offsetting simply by removing the _buggy suffix on the function > > > name and if that causes regressions, it gives us an easy way to revert. > > > > > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > > > Suggested-by: Russell King <linux@armlinux.org.uk> > > > Suggested-by: Matthew Wilcox <willy@infradead.org> > > > --- > > > include/linux/mm.h | 4 +++ > > > mm/memory.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > mm/nommu.c | 14 ++++++++++ > > > 3 files changed, 99 insertions(+) > > > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > > index 80bb640..25752b0 100644 > > > --- a/include/linux/mm.h > > > +++ b/include/linux/mm.h > > > @@ -2565,6 +2565,10 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, > > > int remap_pfn_range(struct vm_area_struct *, unsigned long addr, > > > unsigned long pfn, unsigned long size, pgprot_t); > > > int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *); > > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num); > > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num); > > > vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, > > > unsigned long pfn); > > > vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, > > > diff --git a/mm/memory.c b/mm/memory.c > > > index e11ca9d..0a4bf57 100644 > > > --- a/mm/memory.c > > > +++ b/mm/memory.c > > > @@ -1520,6 +1520,87 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > > > } > > > EXPORT_SYMBOL(vm_insert_page); > > > > > > +/** > > > + * __vm_insert_range - insert range of kernel pages into user vma > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * @offset: user's requested vm_pgoff > > > + * > > > + * This allows drivers to insert range of kernel pages they've allocated > > > + * into a user vma. > > > + * > > > + * If we fail to insert any page into the vma, the function will return > > > + * immediately leaving any previously inserted pages present. Callers > > > + * from the mmap handler may immediately return the error as their caller > > > + * will destroy the vma, removing any successfully inserted pages. Other > > > + * callers should make their own arrangements for calling unmap_region(). > > > + * > > > + * Context: Process context. > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num, unsigned long offset) > > > +{ > > > + unsigned long count = vma_pages(vma); > > > + unsigned long uaddr = vma->vm_start; > > > + int ret, i; > > > + > > > + /* Fail if the user requested offset is beyond the end of the object */ > > > + if (offset > num) > > > + return -ENXIO; > > > + > > > + /* Fail if the user requested size exceeds available object size */ > > > + if (count > num - offset) > > > + return -ENXIO; > > > + > > > + for (i = 0; i < count; i++) { > > > + ret = vm_insert_page(vma, uaddr, pages[offset + i]); > > > + if (ret < 0) > > > + return ret; > > > + uaddr += PAGE_SIZE; > > > + } > > > + > > > + return 0; > > > +} > > > + > > > +/** > > > + * vm_insert_range - insert range of kernel pages starts with non zero offset > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * > > > + * Maps an object consisting of `num' `pages', catering for the user's > > > + * requested vm_pgoff > > > + * > > > > The elaborate description you've added to __vm_insert_range() is better put > > here, as this is the "public" function. > > Ok, will add it in v3. Which means __vm_insert_range() still needs a short > description ? It won't hurt ;-) > > > > > + * Context: Process context. Called by mmap handlers. > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num) > > > +{ > > > + return __vm_insert_range(vma, pages, num, vma->vm_pgoff); > > > +} > > > +EXPORT_SYMBOL(vm_insert_range); > > > + > > > +/** > > > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * > > > + * Maps a set of pages, always starting at page[0] > > > > Here I'd add something like: > > > > Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to > > 0. This function is intended for the drivers that did not consider > > @vm_pgoff. > > Ok. > > > > > > vm_insert_range_buggy() is the API which could be used to map > > > range of kernel memory/pages in drivers which has not considered > > > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > > > > + * > > > + * Context: Process context. Called by mmap handlers. > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num) > > > +{ > > > + return __vm_insert_range(vma, pages, num, 0); > > > +} > > > +EXPORT_SYMBOL(vm_insert_range_buggy); > > > + > > > static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, > > > pfn_t pfn, pgprot_t prot, bool mkwrite) > > > { > > > diff --git a/mm/nommu.c b/mm/nommu.c > > > index 749276b..21d101e 100644 > > > --- a/mm/nommu.c > > > +++ b/mm/nommu.c > > > @@ -473,6 +473,20 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > > > } > > > EXPORT_SYMBOL(vm_insert_page); > > > > > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num) > > > +{ > > > + return -EINVAL; > > > +} > > > +EXPORT_SYMBOL(vm_insert_range); > > > + > > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num) > > > +{ > > > + return -EINVAL; > > > +} > > > +EXPORT_SYMBOL(vm_insert_range_buggy); > > > + > > > /* > > > * sys_brk() for the most part doesn't need the global kernel > > > * lock, except when an application is doing something nasty > > > -- > > > 1.9.1 > > > > > > > -- > > Sincerely yours, > > Mike. > > >
Am Donnerstag, 31. Januar 2019, 04:08:12 CET schrieb Souptick Joarder: > Previouly drivers have their own way of mapping range of > kernel pages/memory into user vma and this was done by > invoking vm_insert_page() within a loop. > > As this pattern is common across different drivers, it can > be generalized by creating new functions and use it across > the drivers. > > vm_insert_range() is the API which could be used to mapped > kernel memory/pages in drivers which has considered vm_pgoff > > vm_insert_range_buggy() is the API which could be used to map > range of kernel memory/pages in drivers which has not considered > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > We _could_ then at a later "fix" these drivers which are using > vm_insert_range_buggy() to behave according to the normal vm_pgoff > offsetting simply by removing the _buggy suffix on the function > name and if that causes regressions, it gives us an easy way to revert. > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > Suggested-by: Russell King <linux@armlinux.org.uk> > Suggested-by: Matthew Wilcox <willy@infradead.org> hmm, I'm missing a changelog here between v1 and v2. Nevertheless I managed to test v1 on Rockchip hardware and display is still working, including talking to Lima via prime. So if there aren't any big changes for v2, on Rockchip Tested-by: Heiko Stuebner <heiko@sntech.de> Heiko
On Thu, Jan 31, 2019 at 5:37 PM Heiko Stuebner <heiko@sntech.de> wrote: > > Am Donnerstag, 31. Januar 2019, 04:08:12 CET schrieb Souptick Joarder: > > Previouly drivers have their own way of mapping range of > > kernel pages/memory into user vma and this was done by > > invoking vm_insert_page() within a loop. > > > > As this pattern is common across different drivers, it can > > be generalized by creating new functions and use it across > > the drivers. > > > > vm_insert_range() is the API which could be used to mapped > > kernel memory/pages in drivers which has considered vm_pgoff > > > > vm_insert_range_buggy() is the API which could be used to map > > range of kernel memory/pages in drivers which has not considered > > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > > > We _could_ then at a later "fix" these drivers which are using > > vm_insert_range_buggy() to behave according to the normal vm_pgoff > > offsetting simply by removing the _buggy suffix on the function > > name and if that causes regressions, it gives us an easy way to revert. > > > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > > Suggested-by: Russell King <linux@armlinux.org.uk> > > Suggested-by: Matthew Wilcox <willy@infradead.org> > > hmm, I'm missing a changelog here between v1 and v2. > Nevertheless I managed to test v1 on Rockchip hardware > and display is still working, including talking to Lima via prime. > > So if there aren't any big changes for v2, on Rockchip > Tested-by: Heiko Stuebner <heiko@sntech.de> Change log is available in [0/9]. Patch [1/9] & [4/9] have no changes between v1 -> v2.
Am Donnerstag, 31. Januar 2019, 13:31:52 CET schrieb Souptick Joarder: > On Thu, Jan 31, 2019 at 5:37 PM Heiko Stuebner <heiko@sntech.de> wrote: > > > > Am Donnerstag, 31. Januar 2019, 04:08:12 CET schrieb Souptick Joarder: > > > Previouly drivers have their own way of mapping range of > > > kernel pages/memory into user vma and this was done by > > > invoking vm_insert_page() within a loop. > > > > > > As this pattern is common across different drivers, it can > > > be generalized by creating new functions and use it across > > > the drivers. > > > > > > vm_insert_range() is the API which could be used to mapped > > > kernel memory/pages in drivers which has considered vm_pgoff > > > > > > vm_insert_range_buggy() is the API which could be used to map > > > range of kernel memory/pages in drivers which has not considered > > > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > > > > > We _could_ then at a later "fix" these drivers which are using > > > vm_insert_range_buggy() to behave according to the normal vm_pgoff > > > offsetting simply by removing the _buggy suffix on the function > > > name and if that causes regressions, it gives us an easy way to revert. > > > > > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > > > Suggested-by: Russell King <linux@armlinux.org.uk> > > > Suggested-by: Matthew Wilcox <willy@infradead.org> > > > > hmm, I'm missing a changelog here between v1 and v2. > > Nevertheless I managed to test v1 on Rockchip hardware > > and display is still working, including talking to Lima via prime. > > > > So if there aren't any big changes for v2, on Rockchip > > Tested-by: Heiko Stuebner <heiko@sntech.de> > > Change log is available in [0/9]. > Patch [1/9] & [4/9] have no changes between v1 -> v2. I never seem to get your cover-letters, so didn't see that, sorry. But great that there weren't changes then :-) Heiko
On Thu, Jan 31, 2019 at 6:04 PM Heiko Stuebner <heiko@sntech.de> wrote: > > Am Donnerstag, 31. Januar 2019, 13:31:52 CET schrieb Souptick Joarder: > > On Thu, Jan 31, 2019 at 5:37 PM Heiko Stuebner <heiko@sntech.de> wrote: > > > > > > Am Donnerstag, 31. Januar 2019, 04:08:12 CET schrieb Souptick Joarder: > > > > Previouly drivers have their own way of mapping range of > > > > kernel pages/memory into user vma and this was done by > > > > invoking vm_insert_page() within a loop. > > > > > > > > As this pattern is common across different drivers, it can > > > > be generalized by creating new functions and use it across > > > > the drivers. > > > > > > > > vm_insert_range() is the API which could be used to mapped > > > > kernel memory/pages in drivers which has considered vm_pgoff > > > > > > > > vm_insert_range_buggy() is the API which could be used to map > > > > range of kernel memory/pages in drivers which has not considered > > > > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > > > > > > > We _could_ then at a later "fix" these drivers which are using > > > > vm_insert_range_buggy() to behave according to the normal vm_pgoff > > > > offsetting simply by removing the _buggy suffix on the function > > > > name and if that causes regressions, it gives us an easy way to revert. > > > > > > > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > > > > Suggested-by: Russell King <linux@armlinux.org.uk> > > > > Suggested-by: Matthew Wilcox <willy@infradead.org> > > > > > > hmm, I'm missing a changelog here between v1 and v2. > > > Nevertheless I managed to test v1 on Rockchip hardware > > > and display is still working, including talking to Lima via prime. > > > > > > So if there aren't any big changes for v2, on Rockchip > > > Tested-by: Heiko Stuebner <heiko@sntech.de> > > > > Change log is available in [0/9]. > > Patch [1/9] & [4/9] have no changes between v1 -> v2. > > I never seem to get your cover-letters, so didn't see that, sorry. I added you in sender list for all cover-letters but it didn't reach your inbox :-) Thanks for reviewing and validating the patch. > > But great that there weren't changes then :-) > > Heiko > >
Hi Mike, On Thu, Jan 31, 2019 at 2:09 PM Mike Rapoport <rppt@linux.ibm.com> wrote: > > On Thu, Jan 31, 2019 at 08:38:12AM +0530, Souptick Joarder wrote: > > Previouly drivers have their own way of mapping range of > > kernel pages/memory into user vma and this was done by > > invoking vm_insert_page() within a loop. > > > > As this pattern is common across different drivers, it can > > be generalized by creating new functions and use it across > > the drivers. > > > > vm_insert_range() is the API which could be used to mapped > > kernel memory/pages in drivers which has considered vm_pgoff > > > > vm_insert_range_buggy() is the API which could be used to map > > range of kernel memory/pages in drivers which has not considered > > vm_pgoff. vm_pgoff is passed default as 0 for those drivers. > > > > We _could_ then at a later "fix" these drivers which are using > > vm_insert_range_buggy() to behave according to the normal vm_pgoff > > offsetting simply by removing the _buggy suffix on the function > > name and if that causes regressions, it gives us an easy way to revert. > > > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > > Suggested-by: Russell King <linux@armlinux.org.uk> > > Suggested-by: Matthew Wilcox <willy@infradead.org> > > --- > > include/linux/mm.h | 4 +++ > > mm/memory.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > mm/nommu.c | 14 ++++++++++ > > 3 files changed, 99 insertions(+) > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index 80bb640..25752b0 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -2565,6 +2565,10 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, > > int remap_pfn_range(struct vm_area_struct *, unsigned long addr, > > unsigned long pfn, unsigned long size, pgprot_t); > > int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *); > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num); > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num); > > vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, > > unsigned long pfn); > > vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, > > diff --git a/mm/memory.c b/mm/memory.c > > index e11ca9d..0a4bf57 100644 > > --- a/mm/memory.c > > +++ b/mm/memory.c > > @@ -1520,6 +1520,87 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > > } > > EXPORT_SYMBOL(vm_insert_page); > > > > +/** > > + * __vm_insert_range - insert range of kernel pages into user vma > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * @offset: user's requested vm_pgoff > > + * > > + * This allows drivers to insert range of kernel pages they've allocated > > + * into a user vma. > > + * > > + * If we fail to insert any page into the vma, the function will return > > + * immediately leaving any previously inserted pages present. Callers > > + * from the mmap handler may immediately return the error as their caller > > + * will destroy the vma, removing any successfully inserted pages. Other > > + * callers should make their own arrangements for calling unmap_region(). > > + * > > + * Context: Process context. > > + * Return: 0 on success and error code otherwise. > > + */ > > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num, unsigned long offset) > > +{ > > + unsigned long count = vma_pages(vma); > > + unsigned long uaddr = vma->vm_start; > > + int ret, i; > > + > > + /* Fail if the user requested offset is beyond the end of the object */ > > + if (offset > num) > > + return -ENXIO; > > + > > + /* Fail if the user requested size exceeds available object size */ > > + if (count > num - offset) > > + return -ENXIO; > > + > > + for (i = 0; i < count; i++) { > > + ret = vm_insert_page(vma, uaddr, pages[offset + i]); > > + if (ret < 0) > > + return ret; > > + uaddr += PAGE_SIZE; > > + } > > + > > + return 0; > > +} > > + > > +/** > > + * vm_insert_range - insert range of kernel pages starts with non zero offset > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * > > + * Maps an object consisting of `num' `pages', catering for the user's > > + * requested vm_pgoff > > + * > > The elaborate description you've added to __vm_insert_range() is better put > here, as this is the "public" function. > > > + * Context: Process context. Called by mmap handlers. > > + * Return: 0 on success and error code otherwise. > > + */ > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > +{ > > + return __vm_insert_range(vma, pages, num, vma->vm_pgoff); > > +} > > +EXPORT_SYMBOL(vm_insert_range); > > + > > +/** > > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * > > + * Maps a set of pages, always starting at page[0] > > Here I'd add something like: > > Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to > 0. This function is intended for the drivers that did not consider > @vm_pgoff. Just thought to take opinion for documentation before placing it in v3. Does it looks fine ? +/** + * __vm_insert_range - insert range of kernel pages into user vma + * @vma: user vma to map to + * @pages: pointer to array of source kernel pages + * @num: number of pages in page array + * @offset: user's requested vm_pgoff + * + * This allow drivers to insert range of kernel pages into a user vma. + * + * Return: 0 on success and error code otherwise. + */ +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, + unsigned long num, unsigned long offset) +/** + * vm_insert_range - insert range of kernel pages starts with non zero offset + * @vma: user vma to map to + * @pages: pointer to array of source kernel pages + * @num: number of pages in page array + * + * Maps an object consisting of `num' `pages', catering for the user's + * requested vm_pgoff + * + * If we fail to insert any page into the vma, the function will return + * immediately leaving any previously inserted pages present. Callers + * from the mmap handler may immediately return the error as their caller + * will destroy the vma, removing any successfully inserted pages. Other + * callers should make their own arrangements for calling unmap_region(). + * + * Context: Process context. Called by mmap handlers. + * Return: 0 on success and error code otherwise. + */ +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +/** + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset + * @vma: user vma to map to + * @pages: pointer to array of source kernel pages + * @num: number of pages in page array + * + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to + * 0. This function is intended for the drivers that did not consider + * @vm_pgoff. + * + * Context: Process context. Called by mmap handlers. + * Return: 0 on success and error code otherwise. + */ +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, + unsigned long num)
Hi Souptick, On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote: > Hi Mike, > > Just thought to take opinion for documentation before placing it in v3. > Does it looks fine ? Overall looks good to me. Several minor points below. > +/** > + * __vm_insert_range - insert range of kernel pages into user vma > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * @offset: user's requested vm_pgoff > + * > + * This allow drivers to insert range of kernel pages into a user vma. allows > + * > + * Return: 0 on success and error code otherwise. > + */ > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num, unsigned long offset) > > > +/** > + * vm_insert_range - insert range of kernel pages starts with non zero offset > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * > + * Maps an object consisting of `num' `pages', catering for the user's @num pages > + * requested vm_pgoff > + * > + * If we fail to insert any page into the vma, the function will return > + * immediately leaving any previously inserted pages present. Callers > + * from the mmap handler may immediately return the error as their caller > + * will destroy the vma, removing any successfully inserted pages. Other > + * callers should make their own arrangements for calling unmap_region(). > + * > + * Context: Process context. Called by mmap handlers. > + * Return: 0 on success and error code otherwise. > + */ > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) > > > +/** > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * > + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to the offset > + * 0. This function is intended for the drivers that did not consider > + * @vm_pgoff. > + * > + * Context: Process context. Called by mmap handlers. > + * Return: 0 on success and error code otherwise. > + */ > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) >
On Thu, Feb 07, 2019 at 09:37:08PM +0530, Souptick Joarder wrote: > On Thu, Feb 7, 2019 at 9:27 PM Mike Rapoport <rppt@linux.ibm.com> wrote: > > > > Hi Souptick, > > > > On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote: > > > Hi Mike, > > > > > > Just thought to take opinion for documentation before placing it in v3. > > > Does it looks fine ? > > > > Overall looks good to me. Several minor points below. > > Thanks Mike. Noted. > Shall I consider it as *Reviewed-by:* with below changes ? Yeah, sure. > > > > > +/** > > > + * __vm_insert_range - insert range of kernel pages into user vma > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * @offset: user's requested vm_pgoff > > > + * > > > + * This allow drivers to insert range of kernel pages into a user vma. > > > > allows > > > + * > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num, unsigned long offset) > > > > > > > > > +/** > > > + * vm_insert_range - insert range of kernel pages starts with non zero offset > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * > > > + * Maps an object consisting of `num' `pages', catering for the user's > > @num pages > > > + * requested vm_pgoff > > > + * > > > + * If we fail to insert any page into the vma, the function will return > > > + * immediately leaving any previously inserted pages present. Callers > > > + * from the mmap handler may immediately return the error as their caller > > > + * will destroy the vma, removing any successfully inserted pages. Other > > > + * callers should make their own arrangements for calling unmap_region(). > > > + * > > > + * Context: Process context. Called by mmap handlers. > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num) > > > > > > > > > +/** > > > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * > > > + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to > > > > the offset > > > > > + * 0. This function is intended for the drivers that did not consider > > > + * @vm_pgoff. > > > + * > > > + * Context: Process context. Called by mmap handlers. > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num) > > > > > > > -- > > Sincerely yours, > > Mike. > > >
On Thu, Feb 7, 2019 at 9:27 PM Mike Rapoport <rppt@linux.ibm.com> wrote: > > Hi Souptick, > > On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote: > > Hi Mike, > > > > Just thought to take opinion for documentation before placing it in v3. > > Does it looks fine ? > > Overall looks good to me. Several minor points below. Thanks Mike. Noted. Shall I consider it as *Reviewed-by:* with below changes ? > > > +/** > > + * __vm_insert_range - insert range of kernel pages into user vma > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * @offset: user's requested vm_pgoff > > + * > > + * This allow drivers to insert range of kernel pages into a user vma. > > allows > > + * > > + * Return: 0 on success and error code otherwise. > > + */ > > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num, unsigned long offset) > > > > > > +/** > > + * vm_insert_range - insert range of kernel pages starts with non zero offset > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * > > + * Maps an object consisting of `num' `pages', catering for the user's > @num pages > > + * requested vm_pgoff > > + * > > + * If we fail to insert any page into the vma, the function will return > > + * immediately leaving any previously inserted pages present. Callers > > + * from the mmap handler may immediately return the error as their caller > > + * will destroy the vma, removing any successfully inserted pages. Other > > + * callers should make their own arrangements for calling unmap_region(). > > + * > > + * Context: Process context. Called by mmap handlers. > > + * Return: 0 on success and error code otherwise. > > + */ > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > > > > > +/** > > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * > > + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to > > the offset > > > + * 0. This function is intended for the drivers that did not consider > > + * @vm_pgoff. > > + * > > + * Context: Process context. Called by mmap handlers. > > + * Return: 0 on success and error code otherwise. > > + */ > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > > > -- > Sincerely yours, > Mike. >
On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote: > Just thought to take opinion for documentation before placing it in v3. > Does it looks fine ? > > +/** > + * __vm_insert_range - insert range of kernel pages into user vma > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * @offset: user's requested vm_pgoff > + * > + * This allow drivers to insert range of kernel pages into a user vma. > + * > + * Return: 0 on success and error code otherwise. > + */ > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num, unsigned long offset) For static functions, I prefer to leave off the second '*', ie make it formatted like a docbook comment, but not be processed like a docbook comment. That avoids cluttering the html with descriptions of internal functions that people can't actually call. > +/** > + * vm_insert_range - insert range of kernel pages starts with non zero offset > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * > + * Maps an object consisting of `num' `pages', catering for the user's Rather than using `num', you should use @num. > + * requested vm_pgoff > + * > + * If we fail to insert any page into the vma, the function will return > + * immediately leaving any previously inserted pages present. Callers > + * from the mmap handler may immediately return the error as their caller > + * will destroy the vma, removing any successfully inserted pages. Other > + * callers should make their own arrangements for calling unmap_region(). > + * > + * Context: Process context. Called by mmap handlers. > + * Return: 0 on success and error code otherwise. > + */ > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) > > > +/** > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > + * @vma: user vma to map to > + * @pages: pointer to array of source kernel pages > + * @num: number of pages in page array > + * > + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to But vm_pgoff isn't a parameter, so it's misleading to format it as such. > + * 0. This function is intended for the drivers that did not consider > + * @vm_pgoff. > + * > + * Context: Process context. Called by mmap handlers. > + * Return: 0 on success and error code otherwise. > + */ > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > + unsigned long num) I don't think we should call it 'buggy'. 'zero' would make more sense as a suffix. Given how this interface has evolved, I'm no longer sure than 'vm_insert_range' makes sense as the name for it. Is it perhaps 'vm_map_object' or 'vm_map_pages'?
On Thu, Feb 7, 2019 at 10:17 PM Matthew Wilcox <willy@infradead.org> wrote: > > On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote: > > Just thought to take opinion for documentation before placing it in v3. > > Does it looks fine ? > > > > +/** > > + * __vm_insert_range - insert range of kernel pages into user vma > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * @offset: user's requested vm_pgoff > > + * > > + * This allow drivers to insert range of kernel pages into a user vma. > > + * > > + * Return: 0 on success and error code otherwise. > > + */ > > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num, unsigned long offset) > > For static functions, I prefer to leave off the second '*', ie make it > formatted like a docbook comment, but not be processed like a docbook > comment. That avoids cluttering the html with descriptions of internal > functions that people can't actually call. > > > +/** > > + * vm_insert_range - insert range of kernel pages starts with non zero offset > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * > > + * Maps an object consisting of `num' `pages', catering for the user's > > Rather than using `num', you should use @num. > > > + * requested vm_pgoff > > + * > > + * If we fail to insert any page into the vma, the function will return > > + * immediately leaving any previously inserted pages present. Callers > > + * from the mmap handler may immediately return the error as their caller > > + * will destroy the vma, removing any successfully inserted pages. Other > > + * callers should make their own arrangements for calling unmap_region(). > > + * > > + * Context: Process context. Called by mmap handlers. > > + * Return: 0 on success and error code otherwise. > > + */ > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > > > > > +/** > > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > > + * @vma: user vma to map to > > + * @pages: pointer to array of source kernel pages > > + * @num: number of pages in page array > > + * > > + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to > > But vm_pgoff isn't a parameter, so it's misleading to format it as such. > > > + * 0. This function is intended for the drivers that did not consider > > + * @vm_pgoff. > > + * > > + * Context: Process context. Called by mmap handlers. > > + * Return: 0 on success and error code otherwise. > > + */ > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > + unsigned long num) > > I don't think we should call it 'buggy'. 'zero' would make more sense > as a suffix. suffix can be *zero or zero_offset* whichever suits better. > > Given how this interface has evolved, I'm no longer sure than > 'vm_insert_range' makes sense as the name for it. Is it perhaps > 'vm_map_object' or 'vm_map_pages'? > I prefer vm_map_pages. Considering it, both the interface name can be changed to *vm_insert_range -> vm_map_pages* and *vm_insert_range_buggy -> vm_map_pages_{zero/zero_offset}. As this is only change in interface name and rest of code remain same shall I post it in v3 ( with additional change log mentioned about interface name changed) ? or, It will be a new patch series ( with carry forward all the Reviewed-by / Tested-by on vm_insert_range/ vm_insert_range_buggy ) ?
On Fri, Feb 8, 2019 at 10:52 AM Souptick Joarder <jrdr.linux@gmail.com> wrote: > > On Thu, Feb 7, 2019 at 10:17 PM Matthew Wilcox <willy@infradead.org> wrote: > > > > On Thu, Feb 07, 2019 at 09:19:47PM +0530, Souptick Joarder wrote: > > > Just thought to take opinion for documentation before placing it in v3. > > > Does it looks fine ? > > > > > > +/** > > > + * __vm_insert_range - insert range of kernel pages into user vma > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * @offset: user's requested vm_pgoff > > > + * > > > + * This allow drivers to insert range of kernel pages into a user vma. > > > + * > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num, unsigned long offset) > > > > For static functions, I prefer to leave off the second '*', ie make it > > formatted like a docbook comment, but not be processed like a docbook > > comment. That avoids cluttering the html with descriptions of internal > > functions that people can't actually call. > > > > > +/** > > > + * vm_insert_range - insert range of kernel pages starts with non zero offset > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * > > > + * Maps an object consisting of `num' `pages', catering for the user's > > > > Rather than using `num', you should use @num. > > > > > + * requested vm_pgoff > > > + * > > > + * If we fail to insert any page into the vma, the function will return > > > + * immediately leaving any previously inserted pages present. Callers > > > + * from the mmap handler may immediately return the error as their caller > > > + * will destroy the vma, removing any successfully inserted pages. Other > > > + * callers should make their own arrangements for calling unmap_region(). > > > + * > > > + * Context: Process context. Called by mmap handlers. > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num) > > > > > > > > > +/** > > > + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset > > > + * @vma: user vma to map to > > > + * @pages: pointer to array of source kernel pages > > > + * @num: number of pages in page array > > > + * > > > + * Similar to vm_insert_range(), except that it explicitly sets @vm_pgoff to > > > > But vm_pgoff isn't a parameter, so it's misleading to format it as such. > > > > > + * 0. This function is intended for the drivers that did not consider > > > + * @vm_pgoff. > > > + * > > > + * Context: Process context. Called by mmap handlers. > > > + * Return: 0 on success and error code otherwise. > > > + */ > > > +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, > > > + unsigned long num) > > > > I don't think we should call it 'buggy'. 'zero' would make more sense > > as a suffix. > > suffix can be *zero or zero_offset* whichever suits better. > > > > > Given how this interface has evolved, I'm no longer sure than > > 'vm_insert_range' makes sense as the name for it. Is it perhaps > > 'vm_map_object' or 'vm_map_pages'? > > > > I prefer vm_map_pages. Considering it, both the interface name can be changed > to *vm_insert_range -> vm_map_pages* and *vm_insert_range_buggy -> > vm_map_pages_{zero/zero_offset}. > > As this is only change in interface name and rest of code remain same > shall I post it in v3 ( with additional change log mentioned about interface > name changed) ? > > or, > > It will be a new patch series ( with carry forward all the Reviewed-by > / Tested-by on > vm_insert_range/ vm_insert_range_buggy ) ? Any suggestion on this minor query ?
diff --git a/include/linux/mm.h b/include/linux/mm.h index 80bb640..25752b0 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2565,6 +2565,10 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, int remap_pfn_range(struct vm_area_struct *, unsigned long addr, unsigned long pfn, unsigned long size, pgprot_t); int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *); +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, + unsigned long num); +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, + unsigned long num); vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn); vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, diff --git a/mm/memory.c b/mm/memory.c index e11ca9d..0a4bf57 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1520,6 +1520,87 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, } EXPORT_SYMBOL(vm_insert_page); +/** + * __vm_insert_range - insert range of kernel pages into user vma + * @vma: user vma to map to + * @pages: pointer to array of source kernel pages + * @num: number of pages in page array + * @offset: user's requested vm_pgoff + * + * This allows drivers to insert range of kernel pages they've allocated + * into a user vma. + * + * If we fail to insert any page into the vma, the function will return + * immediately leaving any previously inserted pages present. Callers + * from the mmap handler may immediately return the error as their caller + * will destroy the vma, removing any successfully inserted pages. Other + * callers should make their own arrangements for calling unmap_region(). + * + * Context: Process context. + * Return: 0 on success and error code otherwise. + */ +static int __vm_insert_range(struct vm_area_struct *vma, struct page **pages, + unsigned long num, unsigned long offset) +{ + unsigned long count = vma_pages(vma); + unsigned long uaddr = vma->vm_start; + int ret, i; + + /* Fail if the user requested offset is beyond the end of the object */ + if (offset > num) + return -ENXIO; + + /* Fail if the user requested size exceeds available object size */ + if (count > num - offset) + return -ENXIO; + + for (i = 0; i < count; i++) { + ret = vm_insert_page(vma, uaddr, pages[offset + i]); + if (ret < 0) + return ret; + uaddr += PAGE_SIZE; + } + + return 0; +} + +/** + * vm_insert_range - insert range of kernel pages starts with non zero offset + * @vma: user vma to map to + * @pages: pointer to array of source kernel pages + * @num: number of pages in page array + * + * Maps an object consisting of `num' `pages', catering for the user's + * requested vm_pgoff + * + * Context: Process context. Called by mmap handlers. + * Return: 0 on success and error code otherwise. + */ +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return __vm_insert_range(vma, pages, num, vma->vm_pgoff); +} +EXPORT_SYMBOL(vm_insert_range); + +/** + * vm_insert_range_buggy - insert range of kernel pages starts with zero offset + * @vma: user vma to map to + * @pages: pointer to array of source kernel pages + * @num: number of pages in page array + * + * Maps a set of pages, always starting at page[0] + * + * Context: Process context. Called by mmap handlers. + * Return: 0 on success and error code otherwise. + */ +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return __vm_insert_range(vma, pages, num, 0); +} +EXPORT_SYMBOL(vm_insert_range_buggy); + static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, pfn_t pfn, pgprot_t prot, bool mkwrite) { diff --git a/mm/nommu.c b/mm/nommu.c index 749276b..21d101e 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -473,6 +473,20 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, } EXPORT_SYMBOL(vm_insert_page); +int vm_insert_range(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return -EINVAL; +} +EXPORT_SYMBOL(vm_insert_range); + +int vm_insert_range_buggy(struct vm_area_struct *vma, struct page **pages, + unsigned long num) +{ + return -EINVAL; +} +EXPORT_SYMBOL(vm_insert_range_buggy); + /* * sys_brk() for the most part doesn't need the global kernel * lock, except when an application is doing something nasty
Previouly drivers have their own way of mapping range of kernel pages/memory into user vma and this was done by invoking vm_insert_page() within a loop. As this pattern is common across different drivers, it can be generalized by creating new functions and use it across the drivers. vm_insert_range() is the API which could be used to mapped kernel memory/pages in drivers which has considered vm_pgoff vm_insert_range_buggy() is the API which could be used to map range of kernel memory/pages in drivers which has not considered vm_pgoff. vm_pgoff is passed default as 0 for those drivers. We _could_ then at a later "fix" these drivers which are using vm_insert_range_buggy() to behave according to the normal vm_pgoff offsetting simply by removing the _buggy suffix on the function name and if that causes regressions, it gives us an easy way to revert. Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Suggested-by: Russell King <linux@armlinux.org.uk> Suggested-by: Matthew Wilcox <willy@infradead.org> --- include/linux/mm.h | 4 +++ mm/memory.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ mm/nommu.c | 14 ++++++++++ 3 files changed, 99 insertions(+)