[PATCH v22 03/31] splice: Rename direct_splice_read() to copy_splice_read()

[PATCH v22 03/31] splice: Rename direct_splice_read() to copy_splice_read()

[David Howells]

Rename direct_splice_read() to copy_splice_read() to better reflect as to
what it does.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: linux-cifs@vger.kernel.org
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---

Notes:
    ver #21)
     - Rename direct_splice_read() to copy_splice_read().

 fs/cifs/cifsfs.c   |  4 ++--
 fs/cifs/file.c     |  2 +-
 fs/splice.c        | 11 +++++------
 include/linux/fs.h |  6 +++---
 4 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 43a4d8603db3..fa2477bbcc86 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1416,7 +1416,7 @@ const struct file_operations cifs_file_direct_ops = {
 	.fsync = cifs_fsync,
 	.flush = cifs_flush,
 	.mmap = cifs_file_mmap,
-	.splice_read = direct_splice_read,
+	.splice_read = copy_splice_read,
 	.splice_write = iter_file_splice_write,
 	.unlocked_ioctl  = cifs_ioctl,
 	.copy_file_range = cifs_copy_file_range,
@@ -1470,7 +1470,7 @@ const struct file_operations cifs_file_direct_nobrl_ops = {
 	.fsync = cifs_fsync,
 	.flush = cifs_flush,
 	.mmap = cifs_file_mmap,
-	.splice_read = direct_splice_read,
+	.splice_read = copy_splice_read,
 	.splice_write = iter_file_splice_write,
 	.unlocked_ioctl  = cifs_ioctl,
 	.copy_file_range = cifs_copy_file_range,
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c5fcefdfd797..023496207c18 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -5091,6 +5091,6 @@ ssize_t cifs_splice_read(struct file *in, loff_t *ppos,
 	if (unlikely(!len))
 		return 0;
 	if (in->f_flags & O_DIRECT)
-		return direct_splice_read(in, ppos, pipe, len, flags);
+		return copy_splice_read(in, ppos, pipe, len, flags);
 	return filemap_splice_read(in, ppos, pipe, len, flags);
 }
diff --git a/fs/splice.c b/fs/splice.c
index 3e06611d19ae..2478e065bc53 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -300,12 +300,11 @@ void splice_shrink_spd(struct splice_pipe_desc *spd)
 }
 
 /*
- * Splice data from an O_DIRECT file into pages and then add them to the output
- * pipe.
+ * Copy data from a file into pages and then splice those into the output pipe.
  */
-ssize_t direct_splice_read(struct file *in, loff_t *ppos,
-			   struct pipe_inode_info *pipe,
-			   size_t len, unsigned int flags)
+ssize_t copy_splice_read(struct file *in, loff_t *ppos,
+			 struct pipe_inode_info *pipe,
+			 size_t len, unsigned int flags)
 {
 	struct iov_iter to;
 	struct bio_vec *bv;
@@ -390,7 +389,7 @@ ssize_t direct_splice_read(struct file *in, loff_t *ppos,
 	kfree(bv);
 	return ret;
 }
-EXPORT_SYMBOL(direct_splice_read);
+EXPORT_SYMBOL(copy_splice_read);
 
 /**
  * generic_file_splice_read - splice data from file to a pipe
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 21a981680856..e3c22efa413e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2752,9 +2752,9 @@ ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,
 ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
 			    struct pipe_inode_info *pipe,
 			    size_t len, unsigned int flags);
-ssize_t direct_splice_read(struct file *in, loff_t *ppos,
-			   struct pipe_inode_info *pipe,
-			   size_t len, unsigned int flags);
+ssize_t copy_splice_read(struct file *in, loff_t *ppos,
+			 struct pipe_inode_info *pipe,
+			 size_t len, unsigned int flags);
 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
 		struct pipe_inode_info *, size_t, unsigned int);
 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,

[PATCH v22 27/31] cifs: Use filemap_splice_read()

[David Howells]

Make cifs use filemap_splice_read() rather than doing its own version of
generic_file_splice_read().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Steve French <smfrench@gmail.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---

Notes:
    ver #21)
     - Switch to filemap_splice_read() rather than generic_file_splice_read().
    
    ver #20)
     - Don't remove the export of filemap_splice_read().
    
    ver #18)
     - Split out from change to generic_file_splice_read().

 fs/cifs/cifsfs.c |  8 ++++----
 fs/cifs/cifsfs.h |  3 ---
 fs/cifs/file.c   | 16 ----------------
 3 files changed, 4 insertions(+), 23 deletions(-)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index fa2477bbcc86..4f4492eb975f 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1376,7 +1376,7 @@ const struct file_operations cifs_file_ops = {
 	.fsync = cifs_fsync,
 	.flush = cifs_flush,
 	.mmap  = cifs_file_mmap,
-	.splice_read = cifs_splice_read,
+	.splice_read = filemap_splice_read,
 	.splice_write = iter_file_splice_write,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
@@ -1396,7 +1396,7 @@ const struct file_operations cifs_file_strict_ops = {
 	.fsync = cifs_strict_fsync,
 	.flush = cifs_flush,
 	.mmap = cifs_file_strict_mmap,
-	.splice_read = cifs_splice_read,
+	.splice_read = filemap_splice_read,
 	.splice_write = iter_file_splice_write,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
@@ -1434,7 +1434,7 @@ const struct file_operations cifs_file_nobrl_ops = {
 	.fsync = cifs_fsync,
 	.flush = cifs_flush,
 	.mmap  = cifs_file_mmap,
-	.splice_read = cifs_splice_read,
+	.splice_read = filemap_splice_read,
 	.splice_write = iter_file_splice_write,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
@@ -1452,7 +1452,7 @@ const struct file_operations cifs_file_strict_nobrl_ops = {
 	.fsync = cifs_strict_fsync,
 	.flush = cifs_flush,
 	.mmap = cifs_file_strict_mmap,
-	.splice_read = cifs_splice_read,
+	.splice_read = filemap_splice_read,
 	.splice_write = iter_file_splice_write,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 74cd6fafb33e..d7274eefc666 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -100,9 +100,6 @@ extern ssize_t cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to);
 extern ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from);
 extern ssize_t cifs_direct_writev(struct kiocb *iocb, struct iov_iter *from);
 extern ssize_t cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from);
-extern ssize_t cifs_splice_read(struct file *in, loff_t *ppos,
-				struct pipe_inode_info *pipe, size_t len,
-				unsigned int flags);
 extern int cifs_flock(struct file *pfile, int cmd, struct file_lock *plock);
 extern int cifs_lock(struct file *, int, struct file_lock *);
 extern int cifs_fsync(struct file *, loff_t, loff_t, int);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 023496207c18..375a8037a3f3 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -5078,19 +5078,3 @@ const struct address_space_operations cifs_addr_ops_smallbuf = {
 	.launder_folio = cifs_launder_folio,
 	.migrate_folio = filemap_migrate_folio,
 };
-
-/*
- * Splice data from a file into a pipe.
- */
-ssize_t cifs_splice_read(struct file *in, loff_t *ppos,
-			 struct pipe_inode_info *pipe, size_t len,
-			 unsigned int flags)
-{
-	if (unlikely(*ppos >= file_inode(in)->i_sb->s_maxbytes))
-		return 0;
-	if (unlikely(!len))
-		return 0;
-	if (in->f_flags & O_DIRECT)
-		return copy_splice_read(in, ppos, pipe, len, flags);
-	return filemap_splice_read(in, ppos, pipe, len, flags);
-}

[PATCH v22 29/31] splice: Remove generic_file_splice_read()

[David Howells]

Remove generic_file_splice_read() as it has been replaced with calls to
filemap_splice_read() and copy_splice_read().

With this, ITER_PIPE is no longer used.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Steve French <smfrench@gmail.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---

Notes:
    ver #21)
     - Move zero-len check to vfs_splice_read().
     - Move s_maxbytes check to filemap_splice_read().
     - DIO (and DAX) are handled by vfs_splice_read().
    
    ver #20)
     - Use s_maxbytes from the backing store (in->f_mapping), not the front
       inode (especially for a blockdev).
    
    ver #18)
     - Split out the change to cifs to make it use generic_file_splice_read().
     - Split out the unexport of filemap_splice_read() (still needed by cifs).

 fs/splice.c        | 43 -------------------------------------------
 include/linux/fs.h |  2 --
 2 files changed, 45 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index 8268248df3a9..9be4cb3b9879 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -386,49 +386,6 @@ ssize_t copy_splice_read(struct file *in, loff_t *ppos,
 }
 EXPORT_SYMBOL(copy_splice_read);
 
-/**
- * generic_file_splice_read - splice data from file to a pipe
- * @in:		file to splice from
- * @ppos:	position in @in
- * @pipe:	pipe to splice to
- * @len:	number of bytes to splice
- * @flags:	splice modifier flags
- *
- * Description:
- *    Will read pages from given file and fill them into a pipe. Can be
- *    used as long as it has more or less sane ->read_iter().
- *
- */
-ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
-				 struct pipe_inode_info *pipe, size_t len,
-				 unsigned int flags)
-{
-	struct iov_iter to;
-	struct kiocb kiocb;
-	int ret;
-
-	iov_iter_pipe(&to, ITER_DEST, pipe, len);
-	init_sync_kiocb(&kiocb, in);
-	kiocb.ki_pos = *ppos;
-	ret = call_read_iter(in, &kiocb, &to);
-	if (ret > 0) {
-		*ppos = kiocb.ki_pos;
-		file_accessed(in);
-	} else if (ret < 0) {
-		/* free what was emitted */
-		pipe_discard_from(pipe, to.start_head);
-		/*
-		 * callers of ->splice_read() expect -EAGAIN on
-		 * "can't put anything in there", rather than -EFAULT.
-		 */
-		if (ret == -EFAULT)
-			ret = -EAGAIN;
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL(generic_file_splice_read);
-
 const struct pipe_buf_operations default_pipe_buf_ops = {
 	.release	= generic_pipe_buf_release,
 	.try_steal	= generic_pipe_buf_try_steal,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e3c22efa413e..08ba2ae1d3ce 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2755,8 +2755,6 @@ ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
 ssize_t copy_splice_read(struct file *in, loff_t *ppos,
 			 struct pipe_inode_info *pipe,
 			 size_t len, unsigned int flags);
-extern ssize_t generic_file_splice_read(struct file *, loff_t *,
-		struct pipe_inode_info *, size_t, unsigned int);
 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
 		struct file *, loff_t *, size_t, unsigned int);
 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,

[PATCH v22 31/31] splice: kdoc for filemap_splice_read() and copy_splice_read()

[David Howells]

Provide kerneldoc comments for filemap_splice_read() and
copy_splice_read().

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christian Brauner <brauner@kernel.org>
cc: Christoph Hellwig <hch@lst.de>
cc: Jens Axboe <axboe@kernel.dk>
cc: Steve French <smfrench@gmail.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
 fs/splice.c  | 21 +++++++++++++++++++--
 mm/filemap.c | 21 ++++++++++++++++++---
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index 9be4cb3b9879..2420ead610a7 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -299,8 +299,25 @@ void splice_shrink_spd(struct splice_pipe_desc *spd)
 	kfree(spd->partial);
 }
 
-/*
- * Copy data from a file into pages and then splice those into the output pipe.
+/**
+ * copy_splice_read -  Copy data from a file and splice the copy into a pipe
+ * @in: The file to read from
+ * @ppos: Pointer to the file position to read from
+ * @pipe: The pipe to splice into
+ * @len: The amount to splice
+ * @flags: The SPLICE_F_* flags
+ *
+ * This function allocates a bunch of pages sufficient to hold the requested
+ * amount of data (but limited by the remaining pipe capacity), passes it to
+ * the file's ->read_iter() to read into and then splices the used pages into
+ * the pipe.
+ *
+ * Return: On success, the number of bytes read will be returned and *@ppos
+ * will be updated if appropriate; 0 will be returned if there is no more data
+ * to be read; -EAGAIN will be returned if the pipe had no space, and some
+ * other negative error code will be returned on error.  A short read may occur
+ * if the pipe has insufficient space, we reach the end of the data or we hit a
+ * hole.
  */
 ssize_t copy_splice_read(struct file *in, loff_t *ppos,
 			 struct pipe_inode_info *pipe,
diff --git a/mm/filemap.c b/mm/filemap.c
index 603b562d69b1..f87e2ad8cff1 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2871,9 +2871,24 @@ size_t splice_folio_into_pipe(struct pipe_inode_info *pipe,
 	return spliced;
 }
 
-/*
- * Splice folios from the pagecache of a buffered (ie. non-O_DIRECT) file into
- * a pipe.
+/**
+ * filemap_splice_read -  Splice data from a file's pagecache into a pipe
+ * @in: The file to read from
+ * @ppos: Pointer to the file position to read from
+ * @pipe: The pipe to splice into
+ * @len: The amount to splice
+ * @flags: The SPLICE_F_* flags
+ *
+ * This function gets folios from a file's pagecache and splices them into the
+ * pipe.  Readahead will be called as necessary to fill more folios.  This may
+ * be used for blockdevs also.
+ *
+ * Return: On success, the number of bytes read will be returned and *@ppos
+ * will be updated if appropriate; 0 will be returned if there is no more data
+ * to be read; -EAGAIN will be returned if the pipe had no space, and some
+ * other negative error code will be returned on error.  A short read may occur
+ * if the pipe has insufficient space, we reach the end of the data or we hit a
+ * hole.
  */
 ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
 			    struct pipe_inode_info *pipe,