[PATCH] cfq-iosched: fix crash in do_div()
authorJens Axboe <axboe@suse.de>
Wed, 14 Jun 2006 17:11:57 +0000 (19:11 +0200)
committerLinus Torvalds <torvalds@g5.osdl.org>
Wed, 14 Jun 2006 17:22:16 +0000 (10:22 -0700)
We don't clear the seek stat values in cfq_alloc_io_context(), and if
->seek_mean is unlucky enough to be set to -36 by chance, the first
invocation of cfq_update_io_seektime() will oops with a divide by zero
in do_div().

Just memset the entire cic instead of filling invididual values
independently.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
block/cfq-iosched.c

index a46d030e092aa60cba5f1b513cde94378f6b9ce7..052b17487625f0edf905feb1beadaec7c8e5fa96 100644 (file)
@@ -1323,17 +1323,12 @@ cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
        struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask);
 
        if (cic) {
-               RB_CLEAR(&cic->rb_node);
-               cic->key = NULL;
-               cic->cfqq[ASYNC] = NULL;
-               cic->cfqq[SYNC] = NULL;
+               memset(cic, 0, sizeof(*cic));
+               RB_CLEAR_COLOR(&cic->rb_node);
                cic->last_end_request = jiffies;
-               cic->ttime_total = 0;
-               cic->ttime_samples = 0;
-               cic->ttime_mean = 0;
+               INIT_LIST_HEAD(&cic->queue_list);
                cic->dtor = cfq_free_io_context;
                cic->exit = cfq_exit_io_context;
-               INIT_LIST_HEAD(&cic->queue_list);
                atomic_inc(&ioc_count);
        }