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| author | NeilBrown <neilb@suse.de> | 2022-05-10 04:20:48 +0300 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-05-10 04:20:48 +0300 |
| commit | cba738f6490953e154d163b2980ad6d7f06307aa (patch) | |
| tree | 356ca9d01361a81151f257ddde45d57be4c13c6d /Documentation/filesystems/locking.rst | |
| parent | 7eadabc05d45ecedc0e8906d1db46bc8cfeb02af (diff) | |
| download | linux-cba738f6490953e154d163b2980ad6d7f06307aa.tar.xz | |
doc: update documentation for swap_activate and swap_rw
This documentation for ->swap_activate() has been out-of-date for a long
time. This patch updates it to match recent changes, and adds
documentation for the associated ->swap_rw()
Link: https://lkml.kernel.org/r/164859778126.29473.6778751233552859461.stgit@noble.brown
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: David Howells <dhowells@redhat.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation/filesystems/locking.rst')
| -rw-r--r-- | Documentation/filesystems/locking.rst | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index c26d854275a0..ef2efa1cb4ec 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -258,8 +258,9 @@ prototypes:: int (*launder_folio)(struct folio *); bool (*is_partially_uptodate)(struct folio *, size_t from, size_t count); int (*error_remove_page)(struct address_space *, struct page *); - int (*swap_activate)(struct file *); + int (*swap_activate)(struct swap_info_struct *sis, struct file *f, sector_t *span) int (*swap_deactivate)(struct file *); + int (*swap_rw)(struct kiocb *iocb, struct iov_iter *iter); locking rules: All except dirty_folio and freepage may block @@ -287,6 +288,7 @@ is_partially_uptodate: yes error_remove_page: yes swap_activate: no swap_deactivate: no +swap_rw: yes, unlocks ====================== ======================== ========= =============== ->write_begin(), ->write_end() and ->readpage() may be called from @@ -386,15 +388,19 @@ cleaned, or an error value if not. Note that in order to prevent the folio getting mapped back in and redirtied, it needs to be kept locked across the entire operation. -->swap_activate will be called with a non-zero argument on -files backing (non block device backed) swapfiles. A return value -of zero indicates success, in which case this file can be used for -backing swapspace. The swapspace operations will be proxied to the -address space operations. +->swap_activate() will be called to prepare the given file for swap. It +should perform any validation and preparation necessary to ensure that +writes can be performed with minimal memory allocation. It should call +add_swap_extent(), or the helper iomap_swapfile_activate(), and return +the number of extents added. If IO should be submitted through +->swap_rw(), it should set SWP_FS_OPS, otherwise IO will be submitted +directly to the block device ``sis->bdev``. ->swap_deactivate() will be called in the sys_swapoff() path after ->swap_activate() returned success. +->swap_rw will be called for swap IO if SWP_FS_OPS was set by ->swap_activate(). + file_lock_operations ==================== |