md/raid10: simplify the splitting of requests.
authorNeilBrown <neilb@suse.com>
Wed, 5 Apr 2017 04:05:51 +0000 (14:05 +1000)
committerShaohua Li <shli@fb.com>
Tue, 11 Apr 2017 17:13:02 +0000 (10:13 -0700)
commitfc9977dd069e4f82fcacb262652117c488647319
tree329ec8a20b630d9f3cfdf2596dfe71ea71368c41
parent673ca68d93879b9ffbbed874c9e70ca6e37cab15
md/raid10: simplify the splitting of requests.

raid10 splits requests in two different ways for two different
reasons.

First, bio_split() is used to ensure the bio fits with a chunk.
Second, multiple r10bio structures are allocated to represent the
different sections that need to go to different devices, to avoid
known bad blocks.

This can be simplified to just use bio_split() once, and not to use
multiple r10bios.
We delay the split until we know a maximum bio size that can
be handled with a single r10bio, and then split the bio and queue
the remainder for later handling.

As with raid1, we allocate a new bio_set to help with the splitting.
It is not correct to use fs_bio_set in a device driver.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
drivers/md/raid10.c
drivers/md/raid10.h