From: NeilBrown <neilb@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>,
David Howells <dhowells@redhat.com>,
linux-nfs@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 03/10] MM: move responsibility for setting SWP_FS_OPS to ->swap_activate
Date: Wed, 30 Mar 2022 10:49:41 +1100 [thread overview]
Message-ID: <164859778123.29473.17908205846599043598.stgit@noble.brown> (raw)
In-Reply-To: <164859751830.29473.5309689752169286816.stgit@noble.brown>
If a filesystem wishes to handle all swap IO itself (via ->direct_IO and
->readpage), rather than just providing devices addresses for
submit_bio(), SWP_FS_OPS must be set.
Currently the protocol for setting this it to have ->swap_activate
return zero. In that case SWP_FS_OPS is set, and add_swap_extent()
is called for the entire file.
This is a little clumsy as different return values for ->swap_activate
have quite different meanings, and it makes it hard to search for which
filesystems require SWP_FS_OPS to be set.
So remove the special meaning of a zero return, and require the
filesystem to set SWP_FS_OPS if it so desires, and to always call
add_swap_extent() as required.
Currently only NFS and CIFS return zero for add_swap_extent().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.de>
---
fs/cifs/file.c | 3 ++-
fs/nfs/file.c | 13 +++++++++++--
include/linux/swap.h | 6 ++++++
mm/swapfile.c | 10 +++-------
4 files changed, 22 insertions(+), 10 deletions(-)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 60f43bff7ccb..050f463580f3 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -4927,7 +4927,8 @@ static int cifs_swap_activate(struct swap_info_struct *sis,
* from reading or writing the file
*/
- return 0;
+ sis->flags |= SWP_FS_OPS;
+ return add_swap_extent(sis, 0, sis->max, 0);
}
static void cifs_swap_deactivate(struct file *file)
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 2df2a5392737..66136dca0ad5 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -488,6 +488,7 @@ static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
{
unsigned long blocks;
long long isize;
+ int ret;
struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
struct inode *inode = file->f_mapping->host;
@@ -500,9 +501,17 @@ static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
return -EINVAL;
}
+ ret = rpc_clnt_swap_activate(clnt);
+ if (ret)
+ return ret;
+ ret = add_swap_extent(sis, 0, sis->max, 0);
+ if (ret < 0) {
+ rpc_clnt_swap_deactivate(clnt);
+ return ret;
+ }
*span = sis->pages;
-
- return rpc_clnt_swap_activate(clnt);
+ sis->flags |= SWP_FS_OPS;
+ return ret;
}
static void nfs_swap_deactivate(struct file *file)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 6bc9e21262de..e18b7edccc1d 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -570,6 +570,12 @@ static inline swp_entry_t get_swap_page(struct page *page)
return entry;
}
+static inline int add_swap_extent(struct swap_info_struct *sis,
+ unsigned long start_page,
+ unsigned long nr_pages, sector_t start_block)
+{
+ return -EINVAL;
+}
#endif /* CONFIG_SWAP */
#ifdef CONFIG_THP_SWAP
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 2650927a009b..8710c9c29862 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2244,13 +2244,9 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
if (mapping->a_ops->swap_activate) {
ret = mapping->a_ops->swap_activate(sis, swap_file, span);
- if (ret >= 0)
- sis->flags |= SWP_ACTIVATED;
- if (!ret) {
- sis->flags |= SWP_FS_OPS;
- ret = add_swap_extent(sis, 0, sis->max, 0);
- *span = sis->pages;
- }
+ if (ret < 0)
+ return ret;
+ sis->flags |= SWP_ACTIVATED;
return ret;
}
next prev parent reply other threads:[~2022-03-29 23:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-29 23:49 [PATCH 00/10] MM changes to improve swap-over-NFS support NeilBrown
2022-03-29 23:49 ` [PATCH 08/10] MM: submit multipage reads for SWP_FS_OPS swap-space NeilBrown
2022-03-29 23:49 ` [PATCH 06/10] MM: perform async writes to SWP_FS_OPS swap-space using ->swap_rw NeilBrown
2022-03-29 23:49 ` [PATCH 05/10] MM: introduce ->swap_rw and use it for reads from SWP_FS_OPS swap-space NeilBrown
2022-03-29 23:49 ` [PATCH 07/10] DOC: update documentation for swap_activate and swap_rw NeilBrown
2022-03-29 23:49 ` [PATCH 02/10] MM: drop swap_dirty_folio NeilBrown
2022-03-29 23:49 ` [PATCH 01/10] MM: create new mm/swap.h header file NeilBrown
2022-03-29 23:49 ` NeilBrown [this message]
2022-03-29 23:49 ` [PATCH 04/10] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space NeilBrown
2022-03-29 23:49 ` [PATCH 09/10] MM: submit multipage write " NeilBrown
2022-04-18 6:59 ` Miaohe Lin
2022-04-26 1:58 ` NeilBrown
2022-03-29 23:49 ` [PATCH 10/10] VFS: Add FMODE_CAN_ODIRECT file flag NeilBrown
2022-03-30 10:26 ` [PATCH 00/10] MM changes to improve swap-over-NFS support David Howells
2022-03-31 1:12 ` NeilBrown
2022-04-19 15:57 ` Geert Uytterhoeven
2022-04-26 2:04 ` NeilBrown
2022-03-31 8:13 ` David Howells
-- strict thread matches above, loose matches on Subject: below --
2022-03-06 23:49 NeilBrown
2022-03-06 23:49 ` [PATCH 03/10] MM: move responsibility for setting SWP_FS_OPS to ->swap_activate NeilBrown
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