@@ -3633,7 +3633,7 @@ 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 = {
@@ -2948,8 +2948,8 @@ 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 *);
@@ -2372,23 +2372,21 @@ static int filemap_read_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: data destination
+ * @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.
- *
- * This is really ugly. But the goto's actually try to clarify some
- * of the logic when it comes to error handling etc.
+ * Read data from the pagecache using the ->readpage address space
+ * operation.
*
* Return:
- * * total number of bytes copied, including those the were already @written
- * * negative error code if nothing was copied
+ * Total number of bytes copied, including those already read by the caller as
+ * passed in the @already_read argument. Negative error code if an error
+ * happened before any bytes were copied.
*/
-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;
@@ -2422,7 +2420,7 @@ 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;
i = 0;
@@ -2482,7 +2480,7 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
copied = copy_page_to_iter(pages[i], offset, bytes, iter);
- written += copied;
+ already_read += copied;
iocb->ki_pos += copied;
ra->prev_pos = iocb->ki_pos;
@@ -2501,9 +2499,9 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
if (pages != pages_onstack)
kfree(pages);
- 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
@@ -2577,7 +2575,7 @@ 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;
}
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 <hch@lst.de> --- fs/btrfs/file.c | 2 +- include/linux/fs.h | 4 ++-- mm/filemap.c | 34 ++++++++++++++++------------------ 3 files changed, 19 insertions(+), 21 deletions(-)