md/raid5: Protect some more code with ->device_lock.

Other places that change or follow dev->towrite and dev->written take
the device_lock as well as the sh->lock.
So it should really be held in these places too.
Also, doing so will allow sh->lock to be discarded.

with merged fixes by: Namhyung Kim <namhyung@gmail.com>

Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index f2f2ab329690ae6beb52dc5d141f3ff8a168810b..9985138f4c04465f8a3414091bc0a8c9ba24f1df 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1021,10 +1021,12 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
                        struct bio *wbi;
 
                        spin_lock(&sh->lock);
+                       spin_lock_irq(&sh->raid_conf->device_lock);
                        chosen = dev->towrite;
                        dev->towrite = NULL;
                        BUG_ON(dev->written);
                        wbi = dev->written = chosen;
+                       spin_unlock_irq(&sh->raid_conf->device_lock);
                        spin_unlock(&sh->lock);
 
                        while (wbi && wbi->bi_sector <
@@ -2141,7 +2143,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
        raid5_conf_t *conf = sh->raid_conf;
        int firstwrite=0;
 
-       pr_debug("adding bh b#%llu to stripe s#%llu\n",
+       pr_debug("adding bi b#%llu to stripe s#%llu\n",
                (unsigned long long)bi->bi_sector,
                (unsigned long long)sh->sector);
 
@@ -2167,19 +2169,6 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
                bi->bi_next = *bip;
        *bip = bi;
        bi->bi_phys_segments++;
-       spin_unlock_irq(&conf->device_lock);
-       spin_unlock(&sh->lock);
-
-       pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
-               (unsigned long long)bi->bi_sector,
-               (unsigned long long)sh->sector, dd_idx);
-
-       if (conf->mddev->bitmap && firstwrite) {
-               bitmap_startwrite(conf->mddev->bitmap, sh->sector,
-                                 STRIPE_SECTORS, 0);
-               sh->bm_seq = conf->seq_flush+1;
-               set_bit(STRIPE_BIT_DELAY, &sh->state);
-       }
 
        if (forwrite) {
                /* check if page is covered */
@@ -2194,6 +2183,19 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
                if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
                        set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
        }
+       spin_unlock_irq(&conf->device_lock);
+       spin_unlock(&sh->lock);
+
+       pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
+               (unsigned long long)(*bip)->bi_sector,
+               (unsigned long long)sh->sector, dd_idx);
+
+       if (conf->mddev->bitmap && firstwrite) {
+               bitmap_startwrite(conf->mddev->bitmap, sh->sector,
+                                 STRIPE_SECTORS, 0);
+               sh->bm_seq = conf->seq_flush+1;
+               set_bit(STRIPE_BIT_DELAY, &sh->state);
+       }
        return 1;
 
  overlap: