md/raid5: make sure to_read and to_write never go negative. (1ed850f3) · Commits · 戴 / test

to_read and to_write are part of the result of analysing a stripe before handling it. Their use is to avoid some loops and tests if the values are known to be zero. Thus it is not a problem if they are a little bit larger than they should be. So decrementing them in handle_failed_stripe serves little value, and due to races it could cause some loops to be skipped incorrectly. So remove those decrements. Reported-by:

"Jianpeng Ma" <majianpeng@gmail.com> Signed-off-by:

NeilBrown <neilb@suse.de>

drivers/md/raid5.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -2507,10 +2507,8 @@ handle_failed_stripe(struct r5conf conf, struct stripe_head sh,
		bi = sh->dev[i].towrite;
		sh->dev[i].towrite = NULL;
		spin_unlock_irq(&sh->stripe_lock);
		if (bi) {
		s->to_write--;
		if (bi)
		bitmap_end = 1;
		}

		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
		wake_up(&conf->wait_for_overlap);
		@@ -2558,7 +2556,6 @@ handle_failed_stripe(struct r5conf conf, struct stripe_head sh,
		spin_unlock_irq(&sh->stripe_lock);
		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
		wake_up(&conf->wait_for_overlap);
		if (bi) s->to_read--;
		while (bi && bi->bi_sector <
		sh->dev[i].sector + STRIPE_SECTORS) {
		struct bio *nextbi =

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