pipe: add pipe_buf_release() helper

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

5 files changed, 25 insertions, 22 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index b50220c75132..d82414a1f936 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1985,10 +1985,9 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 
         ret = fuse_dev_do_write(fud, &cs, len);
 
-        for (idx = 0; idx < nbuf; idx++) {
-                struct pipe_buffer *buf = &bufs[idx];
-                buf->ops->release(pipe, buf);
-        }
+        for (idx = 0; idx < nbuf; idx++)
+                pipe_buf_release(pipe, &bufs[idx]);
+
 out:
         kfree(bufs);
         return ret;
diff --git a/fs/pipe.c b/fs/pipe.c
index 4ebe6b2e5217..67b5f1923835 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -299,8 +299,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
                         }
 
                         if (!buf->len) {
-                                buf->ops = NULL;
-                                ops->release(pipe, buf);
+                                pipe_buf_release(pipe, buf);
                                 curbuf = (curbuf + 1) & (pipe->buffers - 1);
                                 pipe->curbuf = curbuf;
                                 pipe->nrbufs = --bufs;
@@ -664,7 +663,7 @@ void free_pipe_info(struct pipe_inode_info *pipe)
         for (i = 0; i < pipe->buffers; i++) {
                 struct pipe_buffer *buf = pipe->bufs + i;
                 if (buf->ops)
-                        buf->ops->release(pipe, buf);
+                        pipe_buf_release(pipe, buf);
         }
         if (pipe->tmp_page)
                 __free_page(pipe->tmp_page);
diff --git a/fs/splice.c b/fs/splice.c
index 188a386bf379..ae90cd1d2999 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -238,8 +238,7 @@ ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
                 pipe->nrbufs++;
                 return buf->len;
         }
-        buf->ops->release(pipe, buf);
-        buf->ops = NULL;
+        pipe_buf_release(pipe, buf);
         return ret;
 }
 EXPORT_SYMBOL(add_to_pipe);
@@ -516,7 +515,6 @@ static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_des
 
         while (pipe->nrbufs) {
                 struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
-                const struct pipe_buf_operations *ops = buf->ops;
 
                 sd->len = buf->len;
                 if (sd->len > sd->total_len)
@@ -542,8 +540,7 @@ static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_des
                 sd->total_len -= ret;
 
                 if (!buf->len) {
-                        buf->ops = NULL;
-                        ops->release(pipe, buf);
+                        pipe_buf_release(pipe, buf);
                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
                         pipe->nrbufs--;
                         if (pipe->files)
@@ -789,11 +786,9 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
                 while (ret) {
                         struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
                         if (ret >= buf->len) {
-                                const struct pipe_buf_operations *ops = buf->ops;
                                 ret -= buf->len;
                                 buf->len = 0;
-                                buf->ops = NULL;
-                                ops->release(pipe, buf);
+                                pipe_buf_release(pipe, buf);
                                 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
                                 pipe->nrbufs--;
                                 if (pipe->files)
@@ -1032,10 +1027,8 @@ out_release:
         for (i = 0; i < pipe->buffers; i++) {
                 struct pipe_buffer *buf = pipe->bufs + i;
 
-                if (buf->ops) {
-                        buf->ops->release(pipe, buf);
-                        buf->ops = NULL;
-                }
+                if (buf->ops)
+                        pipe_buf_release(pipe, buf);
         }
 
         if (!bytes)
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 10876f3cb3da..d24fa6da6ae3 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -126,6 +126,20 @@ static inline void pipe_buf_get(struct pipe_inode_info *pipe,
         buf->ops->get(pipe, buf);
 }
 
+/**
+ * pipe_buf_release - put a reference to a pipe_buffer
+ * @pipe:       the pipe that the buffer belongs to
+ * @buf:        the buffer to put a reference to
+ */
+static inline void pipe_buf_release(struct pipe_inode_info *pipe,
+                                    struct pipe_buffer *buf)
+{
+        const struct pipe_buf_operations *ops = buf->ops;
+
+        buf->ops = NULL;
+        ops->release(pipe, buf);
+}
+
 /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
    memory allocation, whereas PIPE_BUF makes atomicity guarantees.  */
 #define PIPE_SIZE               PAGE_SIZE
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 659eaafcde65..48b8c27acabb 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -709,9 +709,7 @@ static void pipe_advance(struct iov_iter *i, size_t size)
                 int unused = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
                 /* [curbuf,unused) is in use.  Free [idx,unused) */
                 while (idx != unused) {
-                        buf = &pipe->bufs[idx];
-                        buf->ops->release(pipe, buf);
-                        buf->ops = NULL;
+                        pipe_buf_release(pipe, &pipe->bufs[idx]);
                         idx = next_idx(idx, pipe);
                         pipe->nrbufs--;
                 }