pipe: add pipe_buf_confirm() helper

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

fs/fuse/dev.c

@@ -728,7 +728,7 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
 		struct pipe_buffer *buf = cs->pipebufs;
 
 		if (!cs->write) {
-			err = buf->ops->confirm(cs->pipe, buf);
+			err = pipe_buf_confirm(cs->pipe, buf);
 			if (err)
 				return err;
 
@@ -828,7 +828,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 
 	fuse_copy_finish(cs);
 
-	err = buf->ops->confirm(cs->pipe, buf);
+	err = pipe_buf_confirm(cs->pipe, buf);
 	if (err)
 		return err;
 

fs/pipe.c

@@ -267,7 +267,6 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 		if (bufs) {
 			int curbuf = pipe->curbuf;
 			struct pipe_buffer *buf = pipe->bufs + curbuf;
-			const struct pipe_buf_operations *ops = buf->ops;
 			size_t chars = buf->len;
 			size_t written;
 			int error;
@@ -275,7 +274,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 			if (chars > total_len)
 				chars = total_len;
 
-			error = ops->confirm(pipe, buf);
+			error = pipe_buf_confirm(pipe, buf);
 			if (error) {
 				if (!ret)
 					ret = error;
@@ -382,11 +381,10 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 		int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) &
 							(pipe->buffers - 1);
 		struct pipe_buffer *buf = pipe->bufs + lastbuf;
-		const struct pipe_buf_operations *ops = buf->ops;
 		int offset = buf->offset + buf->len;
 
-		if (ops->can_merge && offset + chars <= PAGE_SIZE) {
-			ret = ops->confirm(pipe, buf);
+		if (buf->ops->can_merge && offset + chars <= PAGE_SIZE) {
+			ret = pipe_buf_confirm(pipe, buf);
 			if (ret)
 				goto out;
 

fs/splice.c

@@ -520,7 +520,7 @@ static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_des
 		if (sd->len > sd->total_len)
 			sd->len = sd->total_len;
 
-		ret = buf->ops->confirm(pipe, buf);
+		ret = pipe_buf_confirm(pipe, buf);
 		if (unlikely(ret)) {
 			if (ret == -ENODATA)
 				ret = 0;
@@ -759,7 +759,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 			if (idx == pipe->buffers - 1)
 				idx = -1;
 
-			ret = buf->ops->confirm(pipe, buf);
+			ret = pipe_buf_confirm(pipe, buf);
 			if (unlikely(ret)) {
 				if (ret == -ENODATA)
 					ret = 0;

include/linux/pipe_fs_i.h

@@ -140,6 +140,17 @@ static inline void pipe_buf_release(struct pipe_inode_info *pipe,
 	ops->release(pipe, buf);
 }
 
+/**
+ * pipe_buf_confirm - verify contents of the pipe buffer
+ * @pipe:	the pipe that the buffer belongs to
+ * @buf:	the buffer to confirm
+ */
+static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,
+				   struct pipe_buffer *buf)
+{
+	return buf->ops->confirm(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
@@ -154,7 +165,6 @@ extern unsigned long pipe_user_pages_hard;
 extern unsigned long pipe_user_pages_soft;
 int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *);
 
-
 /* Drop the inode semaphore and wait for a pipe event, atomically */
 void pipe_wait(struct pipe_inode_info *pipe);