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-rw-r--r--fs/splice.c21
-rw-r--r--mm/filemap.c21
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,