On Mon, 10 Sep 2012 17:22:24 -0700 Kent Overstreet <koverstreet@xxxxxxxxxx>
wrote:
> Had to shuffle the code around a bit (where bi_rw and bi_end_io were
> set), but shouldn't really be anything tricky here
>
> Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
> CC: Jens Axboe <axboe@xxxxxxxxx>
> CC: NeilBrown <neilb@xxxxxxx>
> ---
> drivers/md/raid5.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 7c19dbe..ebe43f7 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -561,14 +561,6 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
> bi = &sh->dev[i].req;
> rbi = &sh->dev[i].rreq; /* For writing to replacement */
>
> - bi->bi_rw = rw;
> - rbi->bi_rw = rw;
> - if (rw & WRITE) {
> - bi->bi_end_io = raid5_end_write_request;
> - rbi->bi_end_io = raid5_end_write_request;
> - } else
> - bi->bi_end_io = raid5_end_read_request;
> -
> rcu_read_lock();
> rrdev = rcu_dereference(conf->disks[i].replacement);
> smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
> @@ -643,7 +635,14 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
>
> set_bit(STRIPE_IO_STARTED, &sh->state);
>
> + bio_reset(bi);
> bi->bi_bdev = rdev->bdev;
> + bi->bi_rw = rw;
> + bi->bi_end_io = (rw & WRITE)
> + ? raid5_end_write_request
> + : raid5_end_read_request;
> + bi->bi_private = sh;
> +
> pr_debug("%s: for %llu schedule op %ld on disc %d\n",
> __func__, (unsigned long long)sh->sector,
> bi->bi_rw, i);
> @@ -657,12 +656,9 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
> if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
> bi->bi_rw |= REQ_FLUSH;
>
> - bi->bi_flags = 1 << BIO_UPTODATE;
> - bi->bi_idx = 0;
> bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
> bi->bi_io_vec[0].bv_offset = 0;
> bi->bi_size = STRIPE_SIZE;
> - bi->bi_next = NULL;
> if (rrdev)
> set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
> generic_make_request(bi);
> @@ -674,7 +670,14 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
>
> set_bit(STRIPE_IO_STARTED, &sh->state);
>
> + bio_reset(rbi);
> rbi->bi_bdev = rrdev->bdev;
> + rbi->bi_rw = rw;
> + rbi->bi_end_io = (rw & WRITE)
> + ? raid5_end_write_request
> + : raid5_end_read_request;
'rbi->bi_end_io' can only ever be raid5_end_write_request. We only get here
on a write.
I'd be OK with
BUG_ON(!(rw & WRITE));
but I don't want the condition in the assignment.
The rest looks quite sane.
Thanks
NeilBrown
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