md/raid5: use bio_inc_remaining() instead of repurposing bi_phys_segments as a counter
md/raid5 needs to keep track of how many stripe_heads are processing a
bio so that it can delay calling bio_endio() until all stripe_heads
have completed. It currently uses 16 bits of ->bi_phys_segments for
this purpose.
16 bits is only enough for 256M requests, and it is possible for a
single bio to be larger than this, which causes problems. Also, the
bio struct contains a larger counter, __bi_remaining, which has a
purpose very similar to the purpose of our counter. So stop using
->bi_phys_segments, and instead use __bi_remaining.
This means we don't need to initialize the counter, as our caller
initializes it to '1'. It also means we can call bio_endio() directly
as it tests this counter internally.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
3 files changed