From e3620a3ad52609f64a2402e4b59300afb4b83b77 Mon Sep 17 00:00:00 2001 From: Jonathan Brassow Date: Thu, 7 Mar 2013 16:22:01 -0600 Subject: [PATCH] MD RAID5: Avoid accessing gendisk or queue structs when not available MD RAID5: Fix kernel oops when RAID4/5/6 is used via device-mapper Commit a9add5d (v3.8-rc1) added blktrace calls to the RAID4/5/6 driver. However, when device-mapper is used to create RAID4/5/6 arrays, the mddev->gendisk and mddev->queue fields are not setup. Therefore, calling things like trace_block_bio_remap will cause a kernel oops. This patch conditionalizes those calls on whether the proper fields exist to make the calls. (Device-mapper will call trace_block_bio_remap on its own.) This patch is suitable for the 3.8.y stable kernel. Cc: stable@vger.kernel.org (v3.8+) Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown --- drivers/md/raid5.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 5601dda1bc40..52ba88a10668 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -674,9 +674,11 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) bi->bi_next = NULL; if (rrdev) set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags); - trace_block_bio_remap(bdev_get_queue(bi->bi_bdev), - bi, disk_devt(conf->mddev->gendisk), - sh->dev[i].sector); + + if (conf->mddev->gendisk) + trace_block_bio_remap(bdev_get_queue(bi->bi_bdev), + bi, disk_devt(conf->mddev->gendisk), + sh->dev[i].sector); generic_make_request(bi); } if (rrdev) { @@ -704,9 +706,10 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) rbi->bi_io_vec[0].bv_offset = 0; rbi->bi_size = STRIPE_SIZE; rbi->bi_next = NULL; - trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev), - rbi, disk_devt(conf->mddev->gendisk), - sh->dev[i].sector); + if (conf->mddev->gendisk) + trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev), + rbi, disk_devt(conf->mddev->gendisk), + sh->dev[i].sector); generic_make_request(rbi); } if (!rdev && !rrdev) { @@ -2835,8 +2838,10 @@ static void handle_stripe_dirtying(struct r5conf *conf, set_bit(STRIPE_HANDLE, &sh->state); if (rmw < rcw && rmw > 0) { /* prefer read-modify-write, but need to get some data */ - blk_add_trace_msg(conf->mddev->queue, "raid5 rmw %llu %d", - (unsigned long long)sh->sector, rmw); + if (conf->mddev->queue) + blk_add_trace_msg(conf->mddev->queue, + "raid5 rmw %llu %d", + (unsigned long long)sh->sector, rmw); for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if ((dev->towrite || i == sh->pd_idx) && @@ -2886,7 +2891,7 @@ static void handle_stripe_dirtying(struct r5conf *conf, } } } - if (rcw) + if (rcw && conf->mddev->queue) blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d", (unsigned long long)sh->sector, rcw, qread, test_bit(STRIPE_DELAYED, &sh->state)); @@ -3993,9 +3998,10 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio) atomic_inc(&conf->active_aligned_reads); spin_unlock_irq(&conf->device_lock); - trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev), - align_bi, disk_devt(mddev->gendisk), - raid_bio->bi_sector); + if (mddev->gendisk) + trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev), + align_bi, disk_devt(mddev->gendisk), + raid_bio->bi_sector); generic_make_request(align_bi); return 1; } else { @@ -4089,7 +4095,8 @@ static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule) } spin_unlock_irq(&conf->device_lock); } - trace_block_unplug(mddev->queue, cnt, !from_schedule); + if (mddev->queue) + trace_block_unplug(mddev->queue, cnt, !from_schedule); kfree(cb); }