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| author | Dan Williams <dan.j.williams@intel.com> | 2018-07-13 21:50:16 -0700 |
|---|---|---|
| committer | Dave Jiang <dave.jiang@intel.com> | 2018-07-23 10:38:06 -0700 |
| commit | c2a7d2a115525d3501d38e23d24875a79a07e15e (patch) | |
| tree | df178de827dbda4bce219d4bfb812581d4883b53 /include | |
| parent | ae1139ece126b8eb6d0770094fbac43ea928d9d9 (diff) | |
| download | linux-stable-c2a7d2a115525d3501d38e23d24875a79a07e15e.tar.gz linux-stable-c2a7d2a115525d3501d38e23d24875a79a07e15e.tar.bz2 linux-stable-c2a7d2a115525d3501d38e23d24875a79a07e15e.zip | |
filesystem-dax: Introduce dax_lock_mapping_entry()
In preparation for implementing support for memory poison (media error)
handling via dax mappings, implement a lock_page() equivalent. Poison
error handling requires rmap and needs guarantees that the page->mapping
association is maintained / valid (inode not freed) for the duration of
the lookup.
In the device-dax case it is sufficient to simply hold a dev_pagemap
reference. In the filesystem-dax case we need to use the entry lock.
Export the entry lock via dax_lock_mapping_entry() that uses
rcu_read_lock() to protect against the inode being freed, and
revalidates the page->mapping association under xa_lock().
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/dax.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/dax.h b/include/linux/dax.h index deb0f663252f..450b28db9533 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -88,6 +88,8 @@ int dax_writeback_mapping_range(struct address_space *mapping, struct block_device *bdev, struct writeback_control *wbc); struct page *dax_layout_busy_page(struct address_space *mapping); +bool dax_lock_mapping_entry(struct page *page); +void dax_unlock_mapping_entry(struct page *page); #else static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize) @@ -119,6 +121,17 @@ static inline int dax_writeback_mapping_range(struct address_space *mapping, { return -EOPNOTSUPP; } + +static inline bool dax_lock_mapping_entry(struct page *page) +{ + if (IS_DAX(page->mapping->host)) + return true; + return false; +} + +static inline void dax_unlock_mapping_entry(struct page *page) +{ +} #endif int dax_read_lock(void); |