Commit eb79f3af authored by NeilBrown's avatar NeilBrown Committed by Andrew Morton
Browse files

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: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> (on Renesas RSK+RZA1 with 32 MiB of SDRAM)
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e1209d3a

fs/nfs/direct.c

+10 −13
Original line number Diff line number Diff line
@@ -153,28 +153,25 @@ nfs_direct_count_bytes(struct nfs_direct_req *dreq, 
}



/**

 * 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)

fs/nfs/file.c

+1 −4
Original line number Diff line number Diff line
@@ -488,10 +488,6 @@ static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file, 
	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 nfs_file_aops = { 
	.error_remove_page = generic_error_remove_page,

	.swap_activate = nfs_swap_activate,

	.swap_deactivate = nfs_swap_deactivate,

	.swap_rw = nfs_swap_rw,

};



/*

include/linux/nfs_fs.h

+1 −1
Original line number Diff line number Diff line
@@ -507,7 +507,7 @@ static inline const struct cred *nfs_file_cred(struct file *file) 
/*

 * 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,