block: cleanup variable naming in get_max_io_size

get_max_io_size has a very odd choice of variables names and
initialization patterns.  Switch to more descriptive names and more
clear initialization of them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220614090934.570632-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-merge.c b/block/blk-merge.c
index df003ec..4da981e 100644 (file)
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -164,18 +164,16 @@ static struct bio *blk_bio_write_zeroes_split(struct request_queue *q,
 static inline unsigned get_max_io_size(struct request_queue *q,
                                       struct bio *bio)
 {
-       unsigned sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector, 0);
-       unsigned max_sectors = sectors;
        unsigned pbs = queue_physical_block_size(q) >> SECTOR_SHIFT;
        unsigned lbs = queue_logical_block_size(q) >> SECTOR_SHIFT;
-       unsigned start_offset = bio->bi_iter.bi_sector & (pbs - 1);
-
-       max_sectors += start_offset;
-       max_sectors &= ~(pbs - 1);
-       if (max_sectors > start_offset)
-               return max_sectors - start_offset;
-
-       return sectors & ~(lbs - 1);
+       unsigned max_sectors, start, end;
+
+       max_sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector, 0);
+       start = bio->bi_iter.bi_sector & (pbs - 1);
+       end = (start + max_sectors) & ~(pbs - 1);
+       if (end > start)
+               return end - start;
+       return max_sectors & ~(lbs - 1);
 }
 
 static inline unsigned get_max_segment_size(const struct request_queue *q,