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See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: CF5A6100011 X-Stat-Signature: 1o993nfwgbhtfxibcz9g7dg7k1nepum9 X-HE-Tag: 1783344187-86935 X-HE-Meta: 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 gJaOC0Mr 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Provide a swap_fs_activate helper that directly sets up swap_fs_ops, and a flag in struct swap_ops to indicate of NOFS swapping is allowed. Signed-off-by: Christoph Hellwig --- Documentation/filesystems/locking.rst | 5 +++-- Documentation/filesystems/vfs.rst | 4 ++-- fs/nfs/file.c | 4 +--- fs/smb/client/file.c | 4 +--- include/linux/swap.h | 6 +++++- mm/page_io.c | 10 +++++++++- mm/swap.h | 22 ++++++++++------------ mm/swapfile.c | 2 -- mm/vmscan.c | 15 +++++++-------- 9 files changed, 38 insertions(+), 34 deletions(-) diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index 08d01bc62c31..1a50d41a39a1 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -355,13 +355,14 @@ 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 +->swap_rw(), it should call swap_fs_activate, 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(). +->swap_rw will be called for swap IO if swap_fs_activate was called by +->swap_activate(). file_lock_operations ==================== diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index 7c753148af88..e7677423a20f 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -977,7 +977,7 @@ cache in your filesystem. The following members are defined: 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 + through ->swap_rw(), it should call swap_fs_activate, otherwise IO will be submitted directly to the block device ``sis->bdev``. ``swap_deactivate`` @@ -985,7 +985,7 @@ cache in your filesystem. The following members are defined: successful. ``swap_rw`` - Called to read or write swap pages when SWP_FS_OPS is set. + Called to read or write swap pages when swap_fs_activate was called. The File Object =============== diff --git a/fs/nfs/file.c b/fs/nfs/file.c index a0d8f1c1cf10..851d93a09988 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -597,7 +597,7 @@ static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file, ret = rpc_clnt_swap_activate(clnt); if (ret) return ret; - ret = add_swap_extent(sis, 0, sis->max, 0); + ret = swap_fs_activate(sis); if (ret < 0) { rpc_clnt_swap_deactivate(clnt); return ret; @@ -607,8 +607,6 @@ static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file, if (cl->rpc_ops->enable_swap) cl->rpc_ops->enable_swap(inode); - - sis->flags |= SWP_FS_OPS; return ret; } diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c index 5a25635bc62a..4b1bc16b8f3f 100644 --- a/fs/smb/client/file.c +++ b/fs/smb/client/file.c @@ -3387,9 +3387,7 @@ static int cifs_swap_activate(struct swap_info_struct *sis, * but we could add call to grab a byte range lock to prevent others * from reading or writing the file */ - - sis->flags |= SWP_FS_OPS; - return add_swap_extent(sis, 0, sis->max, 0); + return swap_fs_activate(sis); } static void cifs_swap_deactivate(struct file *file) diff --git a/include/linux/swap.h b/include/linux/swap.h index 74ceb7a88fd5..bb53601e05b3 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -208,7 +208,6 @@ enum { SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ SWP_BLKDEV = (1 << 6), /* its a block device */ SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */ - SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */ SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */ SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */ SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */ @@ -404,6 +403,7 @@ extern void __meminit kswapd_stop(int nid); #ifdef CONFIG_SWAP +int swap_fs_activate(struct swap_info_struct *sis); int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, unsigned long nr_pages, sector_t start_block); int generic_swapfile_activate(struct swap_info_struct *, struct file *, @@ -530,6 +530,10 @@ static inline bool folio_free_swap(struct folio *folio) return false; } +static inline int swap_fs_activate(struct swap_info_struct *sis) +{ + return -EINVAL; +} static inline int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, unsigned long nr_pages, sector_t start_block) diff --git a/mm/page_io.c b/mm/page_io.c index d2b11db1a57f..1e29b36cec07 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -685,12 +685,20 @@ static bool swap_fs_can_merge(struct folio *folio, struct folio *prev_folio, swap_dev_pos(prev_folio->swap) + prev_folio_size; } -const struct swap_ops swap_fs_ops = { +static const struct swap_ops swap_fs_ops = { + .flags = SWAP_OPS_F_REQUIRE_NOFS, .submit_write = swap_fs_submit_write, .submit_read = swap_fs_submit_read, .can_merge = swap_fs_can_merge, }; +int swap_fs_activate(struct swap_info_struct *sis) +{ + sis->ops = &swap_fs_ops; + return add_swap_extent(sis, 0, sis->max, 0); +} +EXPORT_SYMBOL_GPL(swap_fs_activate); + void swap_write_submit(struct swap_io_ctx *ctx) { if (!ctx->sio) diff --git a/mm/swap.h b/mm/swap.h index 5119feff0e93..0ff2f82eced3 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -84,7 +84,17 @@ struct swap_io_ctx { struct swap_info_struct *sis; }; +/* + * SWAP_OPS_F_REQUIRE_NOFS: + * When set, all reclaim operations must operated as GFS_NOFS and not + * just GFP_NOIO, as GFP_NOIO allocations could recourse into the + * file system backing this swap file. + */ +#define SWAP_OPS_F_REQUIRE_NOFS (1U << 0) + struct swap_ops { + unsigned int flags; + bool (*can_merge)(struct folio *folio, struct folio *prev_folio, size_t prev_folio_size, int rw); void (*submit_write)(struct swap_io_ctx *ctx); @@ -335,11 +345,6 @@ struct folio *swapin_sync(swp_entry_t entry, gfp_t flag, unsigned long orders, void swap_update_readahead(struct folio *folio, struct vm_area_struct *vma, unsigned long addr); -static inline unsigned int folio_swap_flags(struct folio *folio) -{ - return __swap_entry_to_info(folio->swap)->flags; -} - #else /* CONFIG_SWAP */ static inline struct swap_cluster_info *swap_cluster_lock( struct swap_info_struct *si, pgoff_t offset, bool irq) @@ -470,16 +475,9 @@ static inline void __swap_cache_replace_folio(struct swap_cluster_info *ci, struct folio *old, struct folio *new) { } - -static inline unsigned int folio_swap_flags(struct folio *folio) -{ - return 0; -} - #endif /* CONFIG_SWAP */ extern const struct swap_ops swap_bdev_ops; -extern const struct swap_ops swap_fs_ops; int shmem_writeout(struct swap_io_ctx *ctx, struct folio *folio, struct list_head *folio_list); diff --git a/mm/swapfile.c b/mm/swapfile.c index b291510813a6..b0b843372f67 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2957,8 +2957,6 @@ static int setup_swap_extents(struct swap_info_struct *sis, ret = mapping->a_ops->swap_activate(sis, swap_file, span); if (ret < 0) return ret; - if (sis->flags & SWP_FS_OPS) - sis->ops = &swap_fs_ops; sis->flags |= SWP_ACTIVATED; return ret; } diff --git a/mm/vmscan.c b/mm/vmscan.c index 2747ee68d327..ef280a24454f 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1037,16 +1037,15 @@ static bool may_enter_fs(struct folio *folio, gfp_t gfp_mask) { if (gfp_mask & __GFP_FS) return true; - if (!folio_test_swapcache(folio) || !(gfp_mask & __GFP_IO)) - return false; /* - * We can "enter_fs" for swap-cache with only __GFP_IO - * providing this isn't SWP_FS_OPS. - * ->flags can be updated non-atomically, - * but that will never affect SWP_FS_OPS, so the data_race - * is safe. + * We can "enter_fs" for swap-cache with only __GFP_IO unless backed by + * a swapfile that requires GFP_NOFS I/O. */ - return !data_race(folio_swap_flags(folio) & SWP_FS_OPS); + if (folio_test_swapcache(folio) && (gfp_mask & __GFP_IO) && + !(__swap_entry_to_info(folio->swap)->ops->flags & + SWAP_OPS_F_REQUIRE_NOFS)) + return true; + return false; } /* -- 2.53.0