diff options
| -rw-r--r-- | block/blk-merge.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index 58fdc3f8905b..35a8f75cc45d 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -186,6 +186,14 @@ static inline unsigned get_max_io_size(struct bio *bio, return max_sectors & ~(lbs - 1); } +/** + * get_max_segment_size() - maximum number of bytes to add as a single segment + * @lim: Request queue limits. + * @start_page: See below. + * @offset: Offset from @start_page where to add a segment. + * + * Returns the maximum number of bytes that can be added as a single segment. + */ static inline unsigned get_max_segment_size(const struct queue_limits *lim, struct page *start_page, unsigned long offset) { @@ -194,11 +202,10 @@ static inline unsigned get_max_segment_size(const struct queue_limits *lim, offset = mask & (page_to_phys(start_page) + offset); /* - * overflow may be triggered in case of zero page physical address - * on 32bit arch, use queue's max segment size when that happens. + * Prevent an overflow if mask = ULONG_MAX and offset = 0 by adding 1 + * after having calculated the minimum. */ - return min_not_zero(mask - offset + 1, - (unsigned long)lim->max_segment_size); + return min(mask - offset, (unsigned long)lim->max_segment_size - 1) + 1; } /** |