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author | NeilBrown <neilb@suse.com> | 2017-03-15 14:05:12 +1100 |
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committer | Shaohua Li <shli@fb.com> | 2017-03-22 19:15:42 -0700 |
commit | 497280509f32340d90feac030bce18006a3e3605 (patch) | |
tree | 02522e712f7b95b35ab1c23c04702f77b0275028 /drivers/md/raid5.h | |
parent | 48df498daf62e1292868005675331929305067f0 (diff) | |
download | linux-stable-497280509f32340d90feac030bce18006a3e3605.tar.gz linux-stable-497280509f32340d90feac030bce18006a3e3605.tar.bz2 linux-stable-497280509f32340d90feac030bce18006a3e3605.zip |
md/raid5: use md_write_start to count stripes, not bios
We use md_write_start() to increase the count of pending writes, and
md_write_end() to decrement the count. We currently count bios
submitted to md/raid5. Change it count stripe_heads that a WRITE bio
has been attached to.
So now, raid5_make_request() calls md_write_start() and then
md_write_end() to keep the count elevated during the setup of the
request.
add_stripe_bio() calls md_write_start() for each stripe_head, and the
completion routines always call md_write_end(), instead of only
calling it when raid5_dec_bi_active_stripes() returns 0.
make_discard_request also calls md_write_start/end().
The parallel between md_write_{start,end} and use of bi_phys_segments
can be seen in that:
Whenever we set bi_phys_segments to 1, we now call md_write_start.
Whenever we increment it on non-read requests with
raid5_inc_bi_active_stripes(), we now call md_write_start().
Whenever we decrement bi_phys_segments on non-read requsts with
raid5_dec_bi_active_stripes(), we now call md_write_end().
This reduces our dependence on keeping a per-bio count of active
stripes in bi_phys_segments.
md_write_inc() is added which parallels md_write_start(), but requires
that a write has already been started, and is certain never to sleep.
This can be used inside a spinlocked region when adding to a write
request.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5.h')
0 files changed, 0 insertions, 0 deletions