| Message ID | 20241211232754.1583023-6-kaleshsingh@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: Introduce arch_mmap_hint() | expand |
* Kalesh Singh <kaleshsingh@google.com> [241211 18:28]: > Introduce arc arch_mmap_hint() and define HAVE_ARCH_MMAP_HINT. > This is a preparatory patch, no functional change is introduced. You have changed the order of the map fixed check and the len check. I *think* what you have done is correct, but your comment is certainly wrong. Your generic call also has more checks than exist in this version of the code - which, again is probably good, but a functional change surely? > > Signed-off-by: Kalesh Singh <kaleshsingh@google.com> > --- > > Changes in v2: > - MAP_FIXED case is also handled in arch_mmap_hint() since this is just a > special case of the hint addr being "enforced", per Yang Shi. > - Consolidate error handling in arch_mmap_hint(). > > arch/arc/include/asm/pgtable.h | 1 + > arch/arc/mm/mmap.c | 43 +++++++++++++++++----------------- > 2 files changed, 23 insertions(+), 21 deletions(-) > > diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h > index 4cf45a99fd79..af3210ea4888 100644 > --- a/arch/arc/include/asm/pgtable.h > +++ b/arch/arc/include/asm/pgtable.h > @@ -28,6 +28,7 @@ extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE); > > /* to cope with aliasing VIPT cache */ > #define HAVE_ARCH_UNMAPPED_AREA > +#define HAVE_ARCH_MMAP_HINT > > #endif /* __ASSEMBLY__ */ > > diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c > index 2185afe8d59f..df01d4d9964b 100644 > --- a/arch/arc/mm/mmap.c > +++ b/arch/arc/mm/mmap.c > @@ -14,6 +14,26 @@ > > #include <asm/cacheflush.h> > > +unsigned long arch_mmap_hint(struct file *filp, unsigned long addr, > + unsigned long len, unsigned long pgoff, > + unsigned long flags) > +{ > + if (len > TASK_SIZE) > + return -ENOMEM; > + > + /* > + * We enforce the MAP_FIXED case. > + */ > + if (flags & MAP_FIXED) { > + if (flags & MAP_SHARED && > + (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) > + return -EINVAL; > + return addr; > + } > + > + return generic_mmap_hint(filp, addr, len, pgoff, flags); > +} > + > /* > * Ensure that shared mappings are correctly aligned to > * avoid aliasing issues with VIPT caches. > @@ -27,30 +47,11 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, > unsigned long flags, vm_flags_t vm_flags) > { > struct mm_struct *mm = current->mm; > - struct vm_area_struct *vma; > struct vm_unmapped_area_info info = {}; > > - /* > - * We enforce the MAP_FIXED case. > - */ > - if (flags & MAP_FIXED) { > - if (flags & MAP_SHARED && > - (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) > - return -EINVAL; > + addr = arch_mmap_hint(filp, addr, len, pgoff, flags); > + if (addr) > return addr; > - } > - > - if (len > TASK_SIZE) > - return -ENOMEM; > - > - if (addr) { > - addr = PAGE_ALIGN(addr); > - > - vma = find_vma(mm, addr); > - if (TASK_SIZE - len >= addr && > - (!vma || addr + len <= vm_start_gap(vma))) > - return addr; > - } > > info.length = len; > info.low_limit = mm->mmap_base; > -- > 2.47.0.338.g60cca15819-goog > >
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h index 4cf45a99fd79..af3210ea4888 100644 --- a/arch/arc/include/asm/pgtable.h +++ b/arch/arc/include/asm/pgtable.h @@ -28,6 +28,7 @@ extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE); /* to cope with aliasing VIPT cache */ #define HAVE_ARCH_UNMAPPED_AREA +#define HAVE_ARCH_MMAP_HINT #endif /* __ASSEMBLY__ */ diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c index 2185afe8d59f..df01d4d9964b 100644 --- a/arch/arc/mm/mmap.c +++ b/arch/arc/mm/mmap.c @@ -14,6 +14,26 @@ #include <asm/cacheflush.h> +unsigned long arch_mmap_hint(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + if (len > TASK_SIZE) + return -ENOMEM; + + /* + * We enforce the MAP_FIXED case. + */ + if (flags & MAP_FIXED) { + if (flags & MAP_SHARED && + (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) + return -EINVAL; + return addr; + } + + return generic_mmap_hint(filp, addr, len, pgoff, flags); +} + /* * Ensure that shared mappings are correctly aligned to * avoid aliasing issues with VIPT caches. @@ -27,30 +47,11 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long flags, vm_flags_t vm_flags) { struct mm_struct *mm = current->mm; - struct vm_area_struct *vma; struct vm_unmapped_area_info info = {}; - /* - * We enforce the MAP_FIXED case. - */ - if (flags & MAP_FIXED) { - if (flags & MAP_SHARED && - (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) - return -EINVAL; + addr = arch_mmap_hint(filp, addr, len, pgoff, flags); + if (addr) return addr; - } - - if (len > TASK_SIZE) - return -ENOMEM; - - if (addr) { - addr = PAGE_ALIGN(addr); - - vma = find_vma(mm, addr); - if (TASK_SIZE - len >= addr && - (!vma || addr + len <= vm_start_gap(vma))) - return addr; - } info.length = len; info.low_limit = mm->mmap_base;
Introduce arc arch_mmap_hint() and define HAVE_ARCH_MMAP_HINT. This is a preparatory patch, no functional change is introduced. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- Changes in v2: - MAP_FIXED case is also handled in arch_mmap_hint() since this is just a special case of the hint addr being "enforced", per Yang Shi. - Consolidate error handling in arch_mmap_hint(). arch/arc/include/asm/pgtable.h | 1 + arch/arc/mm/mmap.c | 43 +++++++++++++++++----------------- 2 files changed, 23 insertions(+), 21 deletions(-)