fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors

This patch pulls calls to buf->ops->confirm() from all actors passed
(also indirectly) to splice_from_pipe_feed().

Is avoiding the call to buf->ops->confirm() while splice()ing to
/dev/null is an intentional optimization? No other user does that
and this will remove this special case.

Against current linux.git 6313e3c21743cc88bb5bd8aa72948ee1e83937b6.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 14 insertions, 29 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 8f1dfaecc8f0..d2026382ac3e 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -682,19 +682,14 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe,
 {
         struct file *file = sd->u.file;
         loff_t pos = sd->pos;
-        int ret, more;
-
-        ret = buf->ops->confirm(pipe, buf);
-        if (!ret) {
-                more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
-                if (file->f_op && file->f_op->sendpage)
-                        ret = file->f_op->sendpage(file, buf->page, buf->offset,
-                                                   sd->len, &pos, more);
-                else
-                        ret = -EINVAL;
-        }
+        int more;
 
-        return ret;
+        if (!likely(file->f_op && file->f_op->sendpage))
+                return -EINVAL;
+
+        more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
+        return file->f_op->sendpage(file, buf->page, buf->offset,
+                                    sd->len, &pos, more);
 }
 
 /*
@@ -727,13 +722,6 @@ int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
         void *fsdata;
         int ret;
 
-        /*
-         * make sure the data in this buffer is uptodate
-         */
-        ret = buf->ops->confirm(pipe, buf);
-        if (unlikely(ret))
-                return ret;
-
         offset = sd->pos & ~PAGE_CACHE_MASK;
 
         this_len = sd->len;
@@ -805,12 +793,17 @@ int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd,
                 if (sd->len > sd->total_len)
                         sd->len = sd->total_len;
 
-                ret = actor(pipe, buf, sd);
-                if (ret <= 0) {
+                ret = buf->ops->confirm(pipe, buf);
+                if (unlikely(ret)) {
                         if (ret == -ENODATA)
                                 ret = 0;
                         return ret;
                 }
+
+                ret = actor(pipe, buf, sd);
+                if (ret <= 0)
+                        return ret;
+
                 buf->offset += ret;
                 buf->len -= ret;
 
@@ -1044,10 +1037,6 @@ static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
         int ret;
         void *data;
 
-        ret = buf->ops->confirm(pipe, buf);
-        if (ret)
-                return ret;
-
         data = buf->ops->map(pipe, buf, 0);
         ret = kernel_write(sd->u.file, data + buf->offset, sd->len, sd->pos);
         buf->ops->unmap(pipe, buf, data);
@@ -1507,10 +1496,6 @@ static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
         char *src;
         int ret;
 
-        ret = buf->ops->confirm(pipe, buf);
-        if (unlikely(ret))
-                return ret;
-
         /*
          * See if we can use the atomic maps, by prefaulting in the
          * pages and doing an atomic copy