| Message ID | 20201007214925.11181-1-rcampbell@nvidia.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | [v2] ext4/xfs: add page refcount helper | expand |
On Wed 07-10-20 14:49:25, Ralph Campbell wrote: > There are several places where ZONE_DEVICE struct pages assume a reference > count == 1 means the page is idle and free. Instead of open coding this, > add helper functions to hide this detail. > > Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Acked-by: Darrick J. Wong <darrick.wong@oracle.com> > Acked-by: Theodore Ts'o <tytso@mit.edu> # for fs/ext4/inode.c The patch looks good to me. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > > Changes in v2: > I strongly resisted the idea of extending this patch but after Jan > Kara's comment about there being more places that could be cleaned > up, I felt compelled to make this one tensy wensy change to add > a dax_wakeup_page() to match the dax_wait_page(). > I kept the Reviewed/Acked-bys since I don't think this substantially > changes the patch. > > fs/dax.c | 4 ++-- > fs/ext4/inode.c | 5 +---- > fs/xfs/xfs_file.c | 4 +--- > include/linux/dax.h | 15 +++++++++++++++ > mm/memremap.c | 3 ++- > 5 files changed, 21 insertions(+), 10 deletions(-) > > diff --git a/fs/dax.c b/fs/dax.c > index 5b47834f2e1b..85c63f735909 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -358,7 +358,7 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping, > for_each_mapped_pfn(entry, pfn) { > struct page *page = pfn_to_page(pfn); > > - WARN_ON_ONCE(trunc && page_ref_count(page) > 1); > + WARN_ON_ONCE(trunc && !dax_layout_is_idle_page(page)); > WARN_ON_ONCE(page->mapping && page->mapping != mapping); > page->mapping = NULL; > page->index = 0; > @@ -372,7 +372,7 @@ static struct page *dax_busy_page(void *entry) > for_each_mapped_pfn(entry, pfn) { > struct page *page = pfn_to_page(pfn); > > - if (page_ref_count(page) > 1) > + if (!dax_layout_is_idle_page(page)) > return page; > } > return NULL; > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 771ed8b1fadb..132620cbfa13 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3937,10 +3937,7 @@ int ext4_break_layouts(struct inode *inode) > if (!page) > return 0; > > - error = ___wait_var_event(&page->_refcount, > - atomic_read(&page->_refcount) == 1, > - TASK_INTERRUPTIBLE, 0, 0, > - ext4_wait_dax_page(ei)); > + error = dax_wait_page(ei, page, ext4_wait_dax_page); > } while (error == 0); > > return error; > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 3d1b95124744..a5304aaeaa3a 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -749,9 +749,7 @@ xfs_break_dax_layouts( > return 0; > > *retry = true; > - return ___wait_var_event(&page->_refcount, > - atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE, > - 0, 0, xfs_wait_dax_page(inode)); > + return dax_wait_page(inode, page, xfs_wait_dax_page); > } > > int > diff --git a/include/linux/dax.h b/include/linux/dax.h > index b52f084aa643..e2da78e87338 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -243,6 +243,21 @@ static inline bool dax_mapping(struct address_space *mapping) > return mapping->host && IS_DAX(mapping->host); > } > > +static inline bool dax_layout_is_idle_page(struct page *page) > +{ > + return page_ref_count(page) == 1; > +} > + > +static inline void dax_wakeup_page(struct page *page) > +{ > + wake_up_var(&page->_refcount); > +} > + > +#define dax_wait_page(_inode, _page, _wait_cb) \ > + ___wait_var_event(&(_page)->_refcount, \ > + dax_layout_is_idle_page(_page), \ > + TASK_INTERRUPTIBLE, 0, 0, _wait_cb(_inode)) > + > #ifdef CONFIG_DEV_DAX_HMEM_DEVICES > void hmem_register_device(int target_nid, struct resource *r); > #else > diff --git a/mm/memremap.c b/mm/memremap.c > index 2bb276680837..504a10ff2edf 100644 > --- a/mm/memremap.c > +++ b/mm/memremap.c > @@ -12,6 +12,7 @@ > #include <linux/types.h> > #include <linux/wait_bit.h> > #include <linux/xarray.h> > +#include <linux/dax.h> > > static DEFINE_XARRAY(pgmap_array); > > @@ -508,7 +509,7 @@ void free_devmap_managed_page(struct page *page) > { > /* notify page idle for dax */ > if (!is_device_private_page(page)) { > - wake_up_var(&page->_refcount); > + dax_wakeup_page(page); > return; > } > > -- > 2.20.1 >
diff --git a/fs/dax.c b/fs/dax.c index 5b47834f2e1b..85c63f735909 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -358,7 +358,7 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping, for_each_mapped_pfn(entry, pfn) { struct page *page = pfn_to_page(pfn); - WARN_ON_ONCE(trunc && page_ref_count(page) > 1); + WARN_ON_ONCE(trunc && !dax_layout_is_idle_page(page)); WARN_ON_ONCE(page->mapping && page->mapping != mapping); page->mapping = NULL; page->index = 0; @@ -372,7 +372,7 @@ static struct page *dax_busy_page(void *entry) for_each_mapped_pfn(entry, pfn) { struct page *page = pfn_to_page(pfn); - if (page_ref_count(page) > 1) + if (!dax_layout_is_idle_page(page)) return page; } return NULL; diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 771ed8b1fadb..132620cbfa13 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3937,10 +3937,7 @@ int ext4_break_layouts(struct inode *inode) if (!page) return 0; - error = ___wait_var_event(&page->_refcount, - atomic_read(&page->_refcount) == 1, - TASK_INTERRUPTIBLE, 0, 0, - ext4_wait_dax_page(ei)); + error = dax_wait_page(ei, page, ext4_wait_dax_page); } while (error == 0); return error; diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 3d1b95124744..a5304aaeaa3a 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -749,9 +749,7 @@ xfs_break_dax_layouts( return 0; *retry = true; - return ___wait_var_event(&page->_refcount, - atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE, - 0, 0, xfs_wait_dax_page(inode)); + return dax_wait_page(inode, page, xfs_wait_dax_page); } int diff --git a/include/linux/dax.h b/include/linux/dax.h index b52f084aa643..e2da78e87338 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -243,6 +243,21 @@ static inline bool dax_mapping(struct address_space *mapping) return mapping->host && IS_DAX(mapping->host); } +static inline bool dax_layout_is_idle_page(struct page *page) +{ + return page_ref_count(page) == 1; +} + +static inline void dax_wakeup_page(struct page *page) +{ + wake_up_var(&page->_refcount); +} + +#define dax_wait_page(_inode, _page, _wait_cb) \ + ___wait_var_event(&(_page)->_refcount, \ + dax_layout_is_idle_page(_page), \ + TASK_INTERRUPTIBLE, 0, 0, _wait_cb(_inode)) + #ifdef CONFIG_DEV_DAX_HMEM_DEVICES void hmem_register_device(int target_nid, struct resource *r); #else diff --git a/mm/memremap.c b/mm/memremap.c index 2bb276680837..504a10ff2edf 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -12,6 +12,7 @@ #include <linux/types.h> #include <linux/wait_bit.h> #include <linux/xarray.h> +#include <linux/dax.h> static DEFINE_XARRAY(pgmap_array); @@ -508,7 +509,7 @@ void free_devmap_managed_page(struct page *page) { /* notify page idle for dax */ if (!is_device_private_page(page)) { - wake_up_var(&page->_refcount); + dax_wakeup_page(page); return; }