block: only honor SG gap prevention for merges that contain data
authorJens Axboe <axboe@fb.com>
Fri, 29 May 2015 19:10:23 +0000 (13:10 -0600)
committerJens Axboe <axboe@fb.com>
Fri, 29 May 2015 19:10:23 +0000 (13:10 -0600)
commitbeefa6ba7bf304d3de3a02cb7366fb0a7d6b27ab
tree17390185e6e56a3d9bdebd0997d8f95025a30d09
parentf6454b049d81bb3d732b6a8afde08420589c6af9
block: only honor SG gap prevention for merges that contain data

We can safely merge anything that wont generate an SG list entry,
so if the bio is data-less (discard), don't look at potential
SG gaps.

Signed-off-by: Jens Axboe <axboe@fb.com>
block/blk-merge.c