On Tue, 8 Jan 2013, Dan Carpenter wrote:
> Hello Joe Lawrence,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch aa992f57bd76: "md: raid1,10: Handle REQ_WRITE_SAME flag in
> write bios" from Dec 14, 2012, leads to the following Smatch
> complaint:
>
> drivers/md/raid10.c:3630 run()
> error: we previously assumed 'mddev->queue' could be null (see line 3619)
>
> drivers/md/raid10.c
> 3618 chunk_size = mddev->chunk_sectors << 9;
> 3619 if (mddev->queue) {
> ^^^^^^^^^^^^
> Old check.
>
> 3620 blk_queue_max_discard_sectors(mddev->queue,
> 3621 mddev->chunk_sectors);
> 3622 blk_queue_io_min(mddev->queue, chunk_size);
> 3623 if (conf->geo.raid_disks % conf->geo.near_copies)
> 3624 blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
> 3625 else
> 3626 blk_queue_io_opt(mddev->queue, chunk_size *
> 3627 (conf->geo.raid_disks / conf->geo.near_copies));
> 3628 }
> 3629
> 3630 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
> ^^^^^^^^^^^^
> New dereference.
>
> 3631 rdev_for_each(rdev, mddev) {
> 3632 long long diff;
>
> regards,
> dan carpenter
>
Hi Neil,
Here's a revised patch that should make the static checker happy. If you
prefer a second patch instead, let me know.
Regards,
-- Joe
>From 414901de959ea1873187fa3fecf2f00b107d40e2 Mon Sep 17 00:00:00 2001
From: Joe Lawrence <joe.lawrence@xxxxxxxxxxx>
Date: Tue, 8 Jan 2013 23:02:38 -0500
Subject: [PATCH 4/4] md: raid1,10: Handle REQ_WRITE_SAME flag in write bios
Set mddev queue's max_write_same_sectors to its chunk_sector value (before
disk_stack_limits merges the underlying disk limits.) With that in place,
be sure to handle writes coming down from the block layer that have the
REQ_WRITE_SAME flag set. That flag needs to be copied into any newly cloned
write bio.
Signed-off-by: Joe Lawrence <joe.lawrence@xxxxxxxxxxx>
---
drivers/md/raid1.c | 7 ++++++-
drivers/md/raid10.c | 9 +++++++--
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index d5bddfc..6e5d5a5 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1000,6 +1000,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
const unsigned long do_discard = (bio->bi_rw
& (REQ_DISCARD | REQ_SECURE));
+ const unsigned long do_same = (bio->bi_rw & REQ_WRITE_SAME);
struct md_rdev *blocked_rdev;
struct blk_plug_cb *cb;
struct raid1_plug_cb *plug = NULL;
@@ -1301,7 +1302,8 @@ read_again:
conf->mirrors[i].rdev->data_offset);
mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
mbio->bi_end_io = raid1_end_write_request;
- mbio->bi_rw = WRITE | do_flush_fua | do_sync | do_discard;
+ mbio->bi_rw =
+ WRITE | do_flush_fua | do_sync | do_discard | do_same;
mbio->bi_private = r1_bio;
atomic_inc(&r1_bio->remaining);
@@ -2818,6 +2820,9 @@ static int run(struct mddev *mddev)
if (IS_ERR(conf))
return PTR_ERR(conf);
+ if (mddev->queue)
+ blk_queue_max_write_same_sectors(mddev->queue,
+ mddev->chunk_sectors);
rdev_for_each(rdev, mddev) {
if (!mddev->gendisk)
continue;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 64d4824..1a74c12 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1105,6 +1105,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
const unsigned long do_discard = (bio->bi_rw
& (REQ_DISCARD | REQ_SECURE));
+ const unsigned long do_same = (bio->bi_rw & REQ_WRITE_SAME);
unsigned long flags;
struct md_rdev *blocked_rdev;
struct blk_plug_cb *cb;
@@ -1460,7 +1461,8 @@ retry_write:
rdev));
mbio->bi_bdev = rdev->bdev;
mbio->bi_end_io = raid10_end_write_request;
- mbio->bi_rw = WRITE | do_sync | do_fua | do_discard;
+ mbio->bi_rw =
+ WRITE | do_sync | do_fua | do_discard | do_same;
mbio->bi_private = r10_bio;
atomic_inc(&r10_bio->remaining);
@@ -1502,7 +1504,8 @@ retry_write:
r10_bio, rdev));
mbio->bi_bdev = rdev->bdev;
mbio->bi_end_io = raid10_end_write_request;
- mbio->bi_rw = WRITE | do_sync | do_fua | do_discard;
+ mbio->bi_rw =
+ WRITE | do_sync | do_fua | do_discard | do_same;
mbio->bi_private = r10_bio;
atomic_inc(&r10_bio->remaining);
@@ -3569,6 +3572,8 @@ static int run(struct mddev *mddev)
if (mddev->queue) {
blk_queue_max_discard_sectors(mddev->queue,
mddev->chunk_sectors);
+ blk_queue_max_write_same_sectors(mddev->queue,
+ mddev->chunk_sectors);
blk_queue_io_min(mddev->queue, chunk_size);
if (conf->geo.raid_disks % conf->geo.near_copies)
blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
--
1.7.11.7
--
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