From: Christoph Hellwig <h...@lst.de>
Rename generic_file_buffered_read to match the naming of filemap_fault,
also update the written parameter to a more descriptive name and
improve the kerneldoc comment.
Signed-off-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstr...@gmail.com>
---
fs/btrfs/file.c | 2 +-
include/linux/fs.h | 4 ++--
mm/filemap.c | 35 ++++++++++++++++-------------------
3 files changed, 19 insertions(+), 22 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index d81ae1f518f23..b0ff2e62a65ca 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3636,7 +3636,7 @@ static ssize_t btrfs_file_read_iter(struct kiocb *iocb,
struct iov_iter *to)
return ret;
}
- return generic_file_buffered_read(iocb, to, ret);
+ return filemap_read(iocb, to, ret);
}
const struct file_operations btrfs_file_operations = {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 43ba79ddbd680..11a399967ad80 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2985,8 +2985,8 @@ extern ssize_t generic_write_checks(struct kiocb *,
struct iov_iter *);
extern int generic_write_check_limits(struct file *file, loff_t pos,
loff_t *count);
extern int generic_file_rw_checks(struct file *file_in, struct file *file_out);
-extern ssize_t generic_file_buffered_read(struct kiocb *iocb,
- struct iov_iter *to, ssize_t already_read);
+ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *to,
+ ssize_t already_read);
extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
diff --git a/mm/filemap.c b/mm/filemap.c
index 542d9c93732c2..ef910eca9e1a2 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2406,23 +2406,20 @@ static int filemap_get_pages(struct kiocb *iocb, struct
iov_iter *iter,
}
/**
- * generic_file_buffered_read - generic file read routine
- * @iocb: the iocb to read
- * @iter: data destination
- * @written: already copied
+ * filemap_read - Read data from the page cache.
+ * @iocb: The iocb to read.
+ * @iter: Destination for the data.
+ * @already_read: Number of bytes already read by the caller.
*
- * This is a generic file read routine, and uses the
- * mapping->a_ops->readpage() function for the actual low-level stuff.
+ * Copies data from the page cache. If the data is not currently present,
+ * uses the readahead and readpage address_space operations to fetch it.
*
- * This is really ugly. But the goto's actually try to clarify some
- * of the logic when it comes to error handling etc.
- *
- * Return:
- * * total number of bytes copied, including those the were already @written
- * * negative error code if nothing was copied
+ * Return: Total number of bytes copied, including those already read by
+ * the caller. If an error happens before any bytes are copied, returns
+ * a negative error number.
*/
-ssize_t generic_file_buffered_read(struct kiocb *iocb,
- struct iov_iter *iter, ssize_t written)
+ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
+ ssize_t already_read)
{
struct file *filp = iocb->ki_filp;
struct file_ra_state *ra = &filp->f_ra;
@@ -2449,7 +2446,7 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
* can no longer safely return -EIOCBQUEUED. Hence mark
* an async read NOWAIT at that point.
*/
- if ((iocb->ki_flags & IOCB_WAITQ) && written)
+ if ((iocb->ki_flags & IOCB_WAITQ) && already_read)
iocb->ki_flags |= IOCB_NOWAIT;
error = filemap_get_pages(iocb, iter, &pvec);
@@ -2509,7 +2506,7 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
copied = copy_page_to_iter(page, offset, bytes, iter);
- written += copied;
+ already_read += copied;
iocb->ki_pos += copied;
ra->prev_pos = iocb->ki_pos;
@@ -2526,9 +2523,9 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
file_accessed(filp);
- return written ? written : error;
+ return already_read ? already_read : error;
}
-EXPORT_SYMBOL_GPL(generic_file_buffered_read);
+EXPORT_SYMBOL_GPL(filemap_read);
/**
* generic_file_read_iter - generic filesystem read routine
@@ -2603,7 +2600,7 @@ generic_file_read_iter(struct kiocb *iocb, struct
iov_iter *iter)
goto out;
}
- retval = generic_file_buffered_read(iocb, iter, retval);
+ retval = filemap_read(iocb, iter, retval);
out:
return retval;
}
--
2.29.2
