The patch titled
Subject: nfs: rename nfs_direct_IO and use as ->swap_rw
has been added to the -mm tree. Its filename is
nfs-rename-nfs_direct_io-and-use-as-swap_rw.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/nfs-rename-nfs_direct_io-and-use-as-swap_rw.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/nfs-rename-nfs_direct_io-and-use-as-swap_rw.patch
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------------------------------------------------------
From: NeilBrown <neilb@xxxxxxx>
Subject: nfs: rename nfs_direct_IO and use as ->swap_rw
The nfs_direct_IO() exists to support SWAP IO, but hasn't worked for a
while. We now need a ->swap_rw function which behaves slightly
differently, returning zero for success rather than a byte count.
So modify nfs_direct_IO accordingly, rename it, and use it as the
->swap_rw function.
Link: https://lkml.kernel.org/r/165119301493.15698.7491285551903597618.stgit@noble.brown
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> (on Renesas RSK+RZA1 with 32 MiB of SDRAM)
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nfs/direct.c | 23 ++++++++++-------------
fs/nfs/file.c | 5 +----
include/linux/nfs_fs.h | 2 +-
3 files changed, 12 insertions(+), 18 deletions(-)
--- a/fs/nfs/direct.c~nfs-rename-nfs_direct_io-and-use-as-swap_rw
+++ a/fs/nfs/direct.c
@@ -153,28 +153,25 @@ nfs_direct_count_bytes(struct nfs_direct
}
/**
- * nfs_direct_IO - NFS address space operation for direct I/O
+ * nfs_swap_rw - NFS address space operation for swap I/O
* @iocb: target I/O control block
* @iter: I/O buffer
*
- * The presence of this routine in the address space ops vector means
- * the NFS client supports direct I/O. However, for most direct IO, we
- * shunt off direct read and write requests before the VFS gets them,
- * so this method is only ever called for swap.
+ * Perform IO to the swap-file. This is much like direct IO.
*/
-ssize_t nfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+int nfs_swap_rw(struct kiocb *iocb, struct iov_iter *iter)
{
- struct inode *inode = iocb->ki_filp->f_mapping->host;
-
- /* we only support swap file calling nfs_direct_IO */
- if (!IS_SWAPFILE(inode))
- return 0;
+ ssize_t ret;
VM_BUG_ON(iov_iter_count(iter) != PAGE_SIZE);
if (iov_iter_rw(iter) == READ)
- return nfs_file_direct_read(iocb, iter, true);
- return nfs_file_direct_write(iocb, iter, true);
+ ret = nfs_file_direct_read(iocb, iter, true);
+ else
+ ret = nfs_file_direct_write(iocb, iter, true);
+ if (ret < 0)
+ return ret;
+ return 0;
}
static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
--- a/fs/nfs/file.c~nfs-rename-nfs_direct_io-and-use-as-swap_rw
+++ a/fs/nfs/file.c
@@ -488,10 +488,6 @@ static int nfs_swap_activate(struct swap
struct rpc_clnt *clnt = NFS_CLIENT(inode);
struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
- if (!file->f_mapping->a_ops->swap_rw)
- /* Cannot support swap */
- return -EINVAL;
-
spin_lock(&inode->i_lock);
blocks = inode->i_blocks;
isize = inode->i_size;
@@ -549,6 +545,7 @@ const struct address_space_operations nf
.error_remove_page = generic_error_remove_page,
.swap_activate = nfs_swap_activate,
.swap_deactivate = nfs_swap_deactivate,
+ .swap_rw = nfs_swap_rw,
};
/*
--- a/include/linux/nfs_fs.h~nfs-rename-nfs_direct_io-and-use-as-swap_rw
+++ a/include/linux/nfs_fs.h
@@ -507,7 +507,7 @@ static inline const struct cred *nfs_fil
/*
* linux/fs/nfs/direct.c
*/
-extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *);
+int nfs_swap_rw(struct kiocb *iocb, struct iov_iter *iter);
ssize_t nfs_file_direct_read(struct kiocb *iocb,
struct iov_iter *iter, bool swap);
ssize_t nfs_file_direct_write(struct kiocb *iocb,
_
Patches currently in -mm which might be from neilb@xxxxxxx are
mm-create-new-mm-swaph-header-file.patch
mm-drop-swap_dirty_folio.patch
mm-move-responsibility-for-setting-swp_fs_ops-to-swap_activate.patch
mm-reclaim-mustnt-enter-fs-for-swp_fs_ops-swap-space.patch
mm-introduce-swap_rw-and-use-it-for-reads-from-swp_fs_ops-swap-space.patch
nfs-rename-nfs_direct_io-and-use-as-swap_rw.patch
mm-perform-async-writes-to-swp_fs_ops-swap-space-using-swap_rw.patch
doc-update-documentation-for-swap_activate-and-swap_rw.patch
mm-submit-multipage-reads-for-swp_fs_ops-swap-space.patch
mm-submit-multipage-write-for-swp_fs_ops-swap-space.patch
mm-handle-thp-in-swap_page_fs.patch
vfs-add-fmode_can_odirect-file-flag.patch
mm-discard-__gfp_atomic.patch
