pipe: change the ->pin() operation to ->confirm()

The name 'pin' was badly chosen, it doesn't pin a pipe buffer
in the most commonly used sense in the kernel. So change the
name to 'confirm', after debating this issue with Hugh
Dickins a bit.

A good return from ->confirm() means that the buffer is really
there, and that the contents are good.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/block/loop.c

@@ -412,7 +412,7 @@ lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 	size_t size;
 	int ret;
 
-	ret = buf->ops->pin(pipe, buf);
+	ret = buf->ops->confirm(pipe, buf);
 	if (unlikely(ret))
 		return ret;
 

fs/nfsd/vfs.c

@@ -815,7 +815,7 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 	size_t size;
 	int ret;
 
-	ret = buf->ops->pin(pipe, buf);
+	ret = buf->ops->confirm(pipe, buf);
 	if (unlikely(ret))
 		return ret;
 

fs/ocfs2/file.c

@@ -1583,7 +1583,7 @@ static int ocfs2_splice_write_actor(struct pipe_inode_info *pipe,
 	ssize_t copied = 0;
 	struct ocfs2_splice_write_priv sp;
 
-	ret = buf->ops->pin(pipe, buf);
+	ret = buf->ops->confirm(pipe, buf);
 	if (ret)
 		goto out;
 
@@ -1604,7 +1604,7 @@ static int ocfs2_splice_write_actor(struct pipe_inode_info *pipe,
 		 * might enter ocfs2_buffered_write_cluster() more
 		 * than once, so keep track of our progress here.
 		 */
-		copied = ocfs2_buffered_write_cluster(sd->file,
+		copied = ocfs2_buffered_write_cluster(sd->u.file,
 						      (loff_t)sd->pos + total,
 						      count,
 						      ocfs2_map_and_write_splice_data,

fs/pipe.c

@@ -203,7 +203,8 @@ void generic_pipe_buf_get(struct pipe_inode_info *info, struct pipe_buffer *buf)
 	page_cache_get(buf->page);
 }
 
-int generic_pipe_buf_pin(struct pipe_inode_info *info, struct pipe_buffer *buf)
+int generic_pipe_buf_confirm(struct pipe_inode_info *info,
+			     struct pipe_buffer *buf)
 {
 	return 0;
 }
@@ -212,7 +213,7 @@ static const struct pipe_buf_operations anon_pipe_buf_ops = {
 	.can_merge = 1,
 	.map = generic_pipe_buf_map,
 	.unmap = generic_pipe_buf_unmap,
-	.pin = generic_pipe_buf_pin,
+	.confirm = generic_pipe_buf_confirm,
 	.release = anon_pipe_buf_release,
 	.steal = generic_pipe_buf_steal,
 	.get = generic_pipe_buf_get,
@@ -252,7 +253,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
 			if (chars > total_len)
 				chars = total_len;
 
-			error = ops->pin(pipe, buf);
+			error = ops->confirm(pipe, buf);
 			if (error) {
 				if (!ret)
 					error = ret;
@@ -373,7 +374,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
 			int error, atomic = 1;
 			void *addr;
 
-			error = ops->pin(pipe, buf);
+			error = ops->confirm(pipe, buf);
 			if (error)
 				goto out;
 

fs/splice.c

@@ -85,8 +85,8 @@ static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
 	buf->flags &= ~PIPE_BUF_FLAG_LRU;
 }
 
-static int page_cache_pipe_buf_pin(struct pipe_inode_info *pipe,
-				   struct pipe_buffer *buf)
+static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe,
+				       struct pipe_buffer *buf)
 {
 	struct page *page = buf->page;
 	int err;
@@ -127,7 +127,7 @@ static const struct pipe_buf_operations page_cache_pipe_buf_ops = {
 	.can_merge = 0,
 	.map = generic_pipe_buf_map,
 	.unmap = generic_pipe_buf_unmap,
-	.pin = page_cache_pipe_buf_pin,
+	.confirm = page_cache_pipe_buf_confirm,
 	.release = page_cache_pipe_buf_release,
 	.steal = page_cache_pipe_buf_steal,
 	.get = generic_pipe_buf_get,
@@ -147,7 +147,7 @@ static const struct pipe_buf_operations user_page_pipe_buf_ops = {
 	.can_merge = 0,
 	.map = generic_pipe_buf_map,
 	.unmap = generic_pipe_buf_unmap,
-	.pin = generic_pipe_buf_pin,
+	.confirm = generic_pipe_buf_confirm,
 	.release = page_cache_pipe_buf_release,
 	.steal = user_page_pipe_buf_steal,
 	.get = generic_pipe_buf_get,
@@ -525,7 +525,7 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe,
 	loff_t pos = sd->pos;
 	int ret, more;
 
-	ret = buf->ops->pin(pipe, buf);
+	ret = buf->ops->confirm(pipe, buf);
 	if (!ret) {
 		more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
 
@@ -569,7 +569,7 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 	/*
 	 * make sure the data in this buffer is uptodate
 	 */
-	ret = buf->ops->pin(pipe, buf);
+	ret = buf->ops->confirm(pipe, buf);
 	if (unlikely(ret))
 		return ret;
 
@@ -1341,7 +1341,7 @@ static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 	char *src;
 	int ret;
 
-	ret = buf->ops->pin(pipe, buf);
+	ret = buf->ops->confirm(pipe, buf);
 	if (unlikely(ret))
 		return ret;
 

include/linux/pipe_fs_i.h

@@ -35,20 +35,21 @@ struct pipe_inode_info {
 /*
  * Note on the nesting of these functions:
  *
- * ->pin()
+ * ->confirm()
  *	->steal()
  *	...
  *	->map()
  *	...
  *	->unmap()
  *
- * That is, ->map() must be called on a pinned buffer, same goes for ->steal().
+ * That is, ->map() must be called on a confirmed buffer,
+ * same goes for ->steal().
  */
 struct pipe_buf_operations {
 	int can_merge;
 	void * (*map)(struct pipe_inode_info *, struct pipe_buffer *, int);
 	void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *, void *);
-	int (*pin)(struct pipe_inode_info *, struct pipe_buffer *);
+	int (*confirm)(struct pipe_inode_info *, struct pipe_buffer *);
 	void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
 	int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
 	void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
@@ -69,7 +70,7 @@ void __free_pipe_info(struct pipe_inode_info *);
 void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int);
 void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *);
 void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
-int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *);
 int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
 
 #endif

kernel/relay.c

@@ -1055,7 +1055,7 @@ static struct pipe_buf_operations relay_pipe_buf_ops = {
 	.can_merge = 0,
 	.map = generic_pipe_buf_map,
 	.unmap = generic_pipe_buf_unmap,
-	.pin = generic_pipe_buf_pin,
+	.confirm = generic_pipe_buf_confirm,
 	.release = relay_pipe_buf_release,
 	.steal = generic_pipe_buf_steal,
 	.get = generic_pipe_buf_get,