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/[email protected] Fixes: 32c0a6b ("btrfs: add and use readahead_batch_length") Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Reviewed-by: Darrick J. Wong <[email protected]> Reported-by: Linus Torvalds <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
mrcsosa · May 15, 2021 · 076171a · 076171a
1 parent f649dc0
commit 076171a
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Showing 2 changed files with 5 additions and 5 deletions.
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
@@ -394,15 +394,15 @@ 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,
 	};
 
 	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);

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
@@ -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;
 }