->splice_write() via ->write_iter()

iter_file_splice_write() - a ->splice_write() instance that gathers the
pipe buffers, builds a bio_vec-based iov_iter covering those and feeds
it to ->write_iter().  A bunch of simple cases coverted to that...

[AV: fixed the braino spotted by Cyrill]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 1 insertions, 42 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 5446e86d3485..b1c489c1fb2e 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -343,47 +343,6 @@ xfs_file_splice_read(
 }
 
 /*
- * xfs_file_splice_write() does not use xfs_rw_ilock() because
- * generic_file_splice_write() takes the i_mutex itself. This, in theory,
- * couuld cause lock inversions between the aio_write path and the splice path
- * if someone is doing concurrent splice(2) based writes and write(2) based
- * writes to the same inode. The only real way to fix this is to re-implement
- * the generic code here with correct locking orders.
- */
-STATIC ssize_t
-xfs_file_splice_write(
-        struct pipe_inode_info  *pipe,
-        struct file             *outfilp,
-        loff_t                  *ppos,
-        size_t                  count,
-        unsigned int            flags)
-{
-        struct inode            *inode = outfilp->f_mapping->host;
-        struct xfs_inode        *ip = XFS_I(inode);
-        int                     ioflags = 0;
-        ssize_t                 ret;
-
-        XFS_STATS_INC(xs_write_calls);
-
-        if (outfilp->f_mode & FMODE_NOCMTIME)
-                ioflags |= IO_INVIS;
-
-        if (XFS_FORCED_SHUTDOWN(ip->i_mount))
-                return -EIO;
-
-        xfs_ilock(ip, XFS_IOLOCK_EXCL);
-
-        trace_xfs_file_splice_write(ip, count, *ppos, ioflags);
-
-        ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
-        if (ret > 0)
-                XFS_STATS_ADD(xs_write_bytes, ret);
-
-        xfs_iunlock(ip, XFS_IOLOCK_EXCL);
-        return ret;
-}
-
-/*
  * This routine is called to handle zeroing any space in the last block of the
  * file that is beyond the EOF.  We do this since the size is being increased
  * without writing anything to that block and we don't want to read the
@@ -1442,7 +1401,7 @@ const struct file_operations xfs_file_operations = {
         .read_iter      = xfs_file_read_iter,
         .write_iter     = xfs_file_write_iter,
         .splice_read    = xfs_file_splice_read,
-        .splice_write   = xfs_file_splice_write,
+        .splice_write   = iter_file_splice_write,
         .unlocked_ioctl = xfs_file_ioctl,
 #ifdef CONFIG_COMPAT
         .compat_ioctl   = xfs_file_compat_ioctl,