X-Git-Url: http://git.osdn.net/view?a=blobdiff_plain;f=block%2Fcfq-iosched.c;h=23500ac7f0f33b4a016b1743f32d01e47f53c8e5;hb=5142709dda7a1f8ca477bdf70ab72ed65892ad42;hp=f3799432676d53cc3648c9ab6801fe4fd084b911;hpb=aababb9766f0e874da26a17acbbec867bf9501f0;p=android-x86%2Fkernel.git

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f3799432676d..23500ac7f0f3 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2773,11 +2773,14 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
 	smp_wmb();
 	cic->key = cfqd_dead_key(cfqd);
 
+	rcu_read_lock();
 	if (rcu_dereference(ioc->ioc_data) == cic) {
+		rcu_read_unlock();
 		spin_lock(&ioc->lock);
 		rcu_assign_pointer(ioc->ioc_data, NULL);
 		spin_unlock(&ioc->lock);
-	}
+	} else
+		rcu_read_unlock();
 
 	if (cic->cfqq[BLK_RW_ASYNC]) {
 		cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
@@ -3084,7 +3087,8 @@ cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc,
 
 	spin_lock_irqsave(&ioc->lock, flags);
 
-	BUG_ON(ioc->ioc_data == cic);
+	BUG_ON(rcu_dereference_check(ioc->ioc_data,
+		lockdep_is_held(&ioc->lock)) == cic);
 
 	radix_tree_delete(&ioc->radix_root, cfqd->cic_index);
 	hlist_del_rcu(&cic->cic_list);
@@ -3165,7 +3169,7 @@ static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
 		}
 	}
 
-	if (ret)
+	if (ret && ret != -EEXIST)
 		printk(KERN_ERR "cfq: cic link failed!\n");
 
 	return ret;
@@ -3181,6 +3185,7 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 {
 	struct io_context *ioc = NULL;
 	struct cfq_io_context *cic;
+	int ret;
 
 	might_sleep_if(gfp_mask & __GFP_WAIT);
 
@@ -3188,6 +3193,7 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 	if (!ioc)
 		return NULL;
 
+retry:
 	cic = cfq_cic_lookup(cfqd, ioc);
 	if (cic)
 		goto out;
@@ -3196,7 +3202,12 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 	if (cic == NULL)
 		goto err;
 
-	if (cfq_cic_link(cfqd, ioc, cic, gfp_mask))
+	ret = cfq_cic_link(cfqd, ioc, cic, gfp_mask);
+	if (ret == -EEXIST) {
+		/* someone has linked cic to ioc already */
+		cfq_cic_free(cic);
+		goto retry;
+	} else if (ret)
 		goto err_free;
 
 out:
@@ -4011,6 +4022,11 @@ static void *cfq_init_queue(struct request_queue *q)
 
 	if (blkio_alloc_blkg_stats(&cfqg->blkg)) {
 		kfree(cfqg);
+
+		spin_lock(&cic_index_lock);
+		ida_remove(&cic_index_ida, cfqd->cic_index);
+		spin_unlock(&cic_index_lock);
+
 		kfree(cfqd);
 		return NULL;
 	}