Commit 076171a6 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: fix readahead return types 

A readahead request will not allocate more memory than can be represented
by a size_t, even on systems that have HIGHMEM available.  Change the
length functions from returning an loff_t to a size_t.

Link: https://lkml.kernel.org/r/20210510201201.1558972-1-willy@infradead.org


Fixes: 32c0a6bc ("btrfs: add and use readahead_batch_length")
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reported-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f649dc0e

fs/iomap/buffered-io.c

+2 −2
Original line number Diff line number Diff line
@@ -394,7 +394,7 @@ void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops) 
{

	struct inode *inode = rac->mapping->host;

	loff_t pos = readahead_pos(rac);

	loff_t length = readahead_length(rac);

	size_t length = readahead_length(rac);

	struct iomap_readpage_ctx ctx = {

		.rac	= rac,

	};
@@ -402,7 +402,7 @@ void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops) 
	trace_iomap_readahead(inode, readahead_count(rac));



	while (length > 0) {

		loff_t ret = iomap_apply(inode, pos, length, 0, ops,

		ssize_t ret = iomap_apply(inode, pos, length, 0, ops,

				&ctx, iomap_readahead_actor);

		if (ret <= 0) {

			WARN_ON_ONCE(ret == 0);

include/linux/pagemap.h

+3 −3
Original line number Diff line number Diff line
@@ -997,9 +997,9 @@ static inline loff_t readahead_pos(struct readahead_control *rac) 
 * readahead_length - The number of bytes in this readahead request.

 * @rac: The readahead request.

 */

static inline loff_t readahead_length(struct readahead_control *rac)

static inline size_t readahead_length(struct readahead_control *rac)

{

	return (loff_t)rac->_nr_pages * PAGE_SIZE;

	return rac->_nr_pages * PAGE_SIZE;

}



/**
@@ -1024,7 +1024,7 @@ static inline unsigned int readahead_count(struct readahead_control *rac) 
 * readahead_batch_length - The number of bytes in the current batch.

 * @rac: The readahead request.

 */

static inline loff_t readahead_batch_length(struct readahead_control *rac)

static inline size_t readahead_batch_length(struct readahead_control *rac)

{

	return rac->_batch_count * PAGE_SIZE;

}