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nfs: rename nfs_direct_IO and use as ->swap_rw
authorNeilBrown <neilb@suse.de>
Tue, 10 May 2022 01:20:48 +0000 (18:20 -0700)
committerakpm <akpm@linux-foundation.org>
Tue, 10 May 2022 01:20:48 +0000 (18:20 -0700)
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@suse.de>
Reviewed-by: Christoph 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: Andrew Morton <akpm@linux-foundation.org>
fs/nfs/direct.c
fs/nfs/file.c
include/linux/nfs_fs.h

index 11c566d..4eb2a83 100644 (file)
@@ -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)
index 55bc8c8..0e7686a 100644 (file)
@@ -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,
 };
 
 /*
index b48b925..fd55434 100644 (file)
@@ -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,