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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/vfs.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swap_activate() has been out-of-date for a long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/vfs.rst')
| -rw-r--r-- | Documentation/filesystems/vfs.rst | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index 794bd1a66bfb..d4bd213d215b 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -749,8 +749,9 @@ cache in your filesystem. The following members are defined: size_t count); void (*is_dirty_writeback) (struct page *, bool *, bool *); int (*error_remove_page) (struct mapping *mapping, struct page *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); }; ``writepage`` @@ -952,15 +953,21 @@ cache in your filesystem. The following members are defined: unless you have them locked or reference counts increased. ``swap_activate`` - Called when swapon is used on a file to allocate space if - necessary and pin the block lookup information in memory. A - return value of zero indicates success, in which case this file - can be used to back swapspace. + + 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`` Called during swapoff on files where swap_activate was successful. +``swap_rw`` + Called to read or write swap pages when SWP_FS_OPS is set. The File Object =============== |