From: Ralph Campbell <rcampbell@xxxxxxxxxx>
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 <rcampbell@xxxxxxxxxx>
Signed-off-by: Alex Sierra <alex.sierra@xxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: Theodore Ts'o <tytso@xxxxxxx>
Acked-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
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 cd03485867a7..d9b856cf6436 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 5f79d265d06a..99e3ed7bcd06 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3899,10 +3899,7 @@ 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 182b24a14804..f8b3f30d2303 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 22ad207bedf4..57a440666935 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -859,9 +859,7 @@ 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 9fc5f99a0ae2..479939b3be40 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -201,6 +201,16 @@ 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
--
2.30.2
