raid5 overloads bi_phys_segments to count the number of blocks that
the request was broken in to so that it knows when the bio is completely handled.
Accessing this must always be done under a spinlock. In one case we
also call bi_end_io under that spinlock, which probably isn't ideal as
bi_end_io could be expensive (even though it isn't allowed to sleep).
So we reducde the range of the spinlock to just accessing bi_phys_segments.
Signed-off-by: Neil Brown <[email protected]>
### Diffstat output
./drivers/md/raid5.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff ./drivers/md/raid5.c~current~ ./drivers/md/raid5.c
--- ./drivers/md/raid5.c~current~ 2006-03-24 14:01:30.000000000 +1100
+++ ./drivers/md/raid5.c 2006-03-24 14:06:47.000000000 +1100
@@ -1743,6 +1743,7 @@ static int make_request(request_queue_t
sector_t logical_sector, last_sector;
struct stripe_head *sh;
const int rw = bio_data_dir(bi);
+ int remaining;
if (unlikely(bio_barrier(bi))) {
bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
@@ -1852,7 +1853,9 @@ static int make_request(request_queue_t
}
spin_lock_irq(&conf->device_lock);
- if (--bi->bi_phys_segments == 0) {
+ remaining = --bi->bi_phys_segments;
+ spin_unlock_irq(&conf->device_lock);
+ if (remaining == 0) {
int bytes = bi->bi_size;
if ( bio_data_dir(bi) == WRITE )
@@ -1860,7 +1863,6 @@ static int make_request(request_queue_t
bi->bi_size = 0;
bi->bi_end_io(bi, bytes, 0);
}
- spin_unlock_irq(&conf->device_lock);
return 0;
}
-
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