[PATCH v1 1/2] ext4/xfs: add page refcount helper
From: Alex Sierra <hidden>
Date: 2021-11-15 19:33:35
Also in:
amd-gfx, dri-devel, linux-mm, linux-xfs
Subsystem:
ext4 file system, filesystem direct access (dax), filesystems (vfs and infrastructure), fuse: filesystem in userspace, the rest, xfs filesystem · Maintainers:
"Theodore Ts'o", Dan Williams, Alexander Viro, Christian Brauner, Miklos Szeredi, Linus Torvalds, Carlos Maiolino
From: Ralph Campbell <redacted> 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 a helper function to hide this detail. Signed-off-by: Ralph Campbell <redacted> Signed-off-by: Alex Sierra <redacted> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Theodore Ts'o <tytso@mit.edu> Acked-by: Darrick J. Wong <djwong@kernel.org> --- v3: [AS]: rename dax_layout_is_idle_page func to dax_page_unused v4: [AS]: This ref count functionality was missing on fuse/dax.c. --- fs/dax.c | 4 ++-- fs/ext4/inode.c | 5 +---- fs/fuse/dax.c | 4 +--- fs/xfs/xfs_file.c | 4 +--- include/linux/dax.h | 10 ++++++++++ 5 files changed, 15 insertions(+), 12 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 4e3e5a283a91..84803c835650 100644
--- a/fs/dax.c
+++ b/fs/dax.c@@ -369,7 +369,7 @@ 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_page_unused(page)); WARN_ON_ONCE(page->mapping && page->mapping != mapping); page->mapping = NULL; page->index = 0;
@@ -383,7 +383,7 @@ 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_page_unused(page)) return page; } return NULL;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0f06305167d5..068e8f78ec02 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c@@ -3913,10 +3913,7 @@ 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(inode)); + error = dax_wait_page(inode, page, ext4_wait_dax_page); } while (error == 0); return error;
diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
index 281d79f8b3d3..f6d2a36e56e2 100644
--- a/fs/fuse/dax.c
+++ b/fs/fuse/dax.c@@ -676,9 +676,7 @@ static int __fuse_dax_break_layouts(struct inode *inode, bool *retry, return 0; *retry = true; - return ___wait_var_event(&page->_refcount, - atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE, - 0, 0, fuse_wait_dax_page(inode)); + return dax_wait_page(inode, page, fuse_wait_dax_page); } /* dmap_end == 0 leads to unmapping of whole file */
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 7aa943edfc02..fb13b12fd032 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c@@ -860,9 +860,7 @@ 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 2619d94c308d..c9c27fbf0b98 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h@@ -216,6 +216,16 @@ static inline bool dax_mapping(struct address_space *mapping) return mapping->host && IS_DAX(mapping->host); } +static inline bool dax_page_unused(struct page *page) +{ + return page_ref_count(page) == 1; +} + +#define dax_wait_page(_inode, _page, _wait_cb) \ + ___wait_var_event(&(_page)->_refcount, \ + dax_page_unused(_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
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2.32.0