Re: [PATCH v1 01/14] ext4/xfs: add page refcount helper
On Tue, Aug 24, 2021 at 10:48:15PM -0500, Alex Sierra wrote:
> From: Ralph Campbell
>
> 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
> Signed-off-by: Alex Sierra
> Reviewed-by: Christoph Hellwig
Looks fine to me,
Acked-by: Darrick J. Wong
--D
> ---
> 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 62352cbcf0f4..c387d09e3e5a 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 fe6045a46599..05ffe6875cb1 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3971,10 +3971,7 @@ int ext4_break_layouts(struct inode *inode)
> if (!page)
> return 0;
>
> - error = ___wait_var_event(>_refcount,
> - atomic_read(>_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/fuse/dax.c b/fs/fuse/dax.c
> index ff99ab2a3c43..2b1f190ba78a 100644
> --- a/fs/fuse/dax.c
> +++ b/fs/fuse/dax.c
> @@ -677,9 +677,7 @@ static int __fuse_dax_break_layouts(struct inode *inode,
> bool *retry,
> return 0;
>
> *retry = true;
> - return ___wait_var_event(>_refcount,
> - atomic_read(>_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 396ef36dcd0a..182057281086 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -840,9 +840,7 @@ xfs_break_dax_layouts(
> return 0;
>
> *retry = true;
> - return ___wait_var_event(>_refcount,
> - atomic_read(>_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..8b5da1d60dbc 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -243,6 +243,16 @@ 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
> --
> 2.32.0
>
Re: [PATCH v1 01/14] ext4/xfs: add page refcount helper
On Tue, Aug 24, 2021 at 10:48:15PM -0500, Alex Sierra wrote: > From: Ralph Campbell > > 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 > Signed-off-by: Alex Sierra > Reviewed-by: Christoph Hellwig Acked-by: Theodore Ts'o
[PATCH v1 01/14] ext4/xfs: add page refcount helper
From: Ralph Campbell
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
Signed-off-by: Alex Sierra
Reviewed-by: Christoph Hellwig
---
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 62352cbcf0f4..c387d09e3e5a 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 fe6045a46599..05ffe6875cb1 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3971,10 +3971,7 @@ int ext4_break_layouts(struct inode *inode)
if (!page)
return 0;
- error = ___wait_var_event(>_refcount,
- atomic_read(>_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/fuse/dax.c b/fs/fuse/dax.c
index ff99ab2a3c43..2b1f190ba78a 100644
--- a/fs/fuse/dax.c
+++ b/fs/fuse/dax.c
@@ -677,9 +677,7 @@ static int __fuse_dax_break_layouts(struct inode *inode,
bool *retry,
return 0;
*retry = true;
- return ___wait_var_event(>_refcount,
- atomic_read(>_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 396ef36dcd0a..182057281086 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -840,9 +840,7 @@ xfs_break_dax_layouts(
return 0;
*retry = true;
- return ___wait_var_event(>_refcount,
- atomic_read(>_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..8b5da1d60dbc 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -243,6 +243,16 @@ 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
--
2.32.0
