[PATCH] ll_rw_blk: prevent huge request allocations

[linux-2.6-omap-h63xx.git] / drivers / block / ll_rw_blk.c

diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index 234fdcfbdf01105e9337e164f34a07dd7dfede5b..6c98cf04271407163e6c201922a20675b9b6ebd8 100644 (file)
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -1912,6 +1912,15 @@ static struct request *get_request(request_queue_t *q, int rw, struct bio *bio,
        }
 
 get_rq:
+       /*
+        * Only allow batching queuers to allocate up to 50% over the defined
+        * limit of requests, otherwise we could have thousands of requests
+        * allocated with any setting of ->nr_requests
+        */
+       if (rl->count[rw] >= (3 * q->nr_requests / 2)) {
+               spin_unlock_irq(q->queue_lock);
+               goto out;
+       }
        rl->count[rw]++;
        rl->starved[rw] = 0;
        if (rl->count[rw] >= queue_congestion_on_threshold(q))