1 files changed, 50 insertions, 23 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 55a7dc227dfb..b6f20be0fc78 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -175,7 +175,7 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q,
 			continue;
 
 		/* alloc per-policy data and attach it to blkg */
-		pd = pol->pd_alloc_fn(gfp_mask, q->node);
+		pd = pol->pd_alloc_fn(gfp_mask, q, blkcg);
 		if (!pd)
 			goto err_free;
 
@@ -755,6 +755,44 @@ static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg,
 
 /**
  * blkg_conf_prep - parse and prepare for per-blkg config update
+ * @inputp: input string pointer
+ *
+ * Parse the device node prefix part, MAJ:MIN, of per-blkg config update
+ * from @input and get and return the matching gendisk.  *@inputp is
+ * updated to point past the device node prefix.  Returns an ERR_PTR()
+ * value on error.
+ *
+ * Use this function iff blkg_conf_prep() can't be used for some reason.
+ */
+struct gendisk *blkcg_conf_get_disk(char **inputp)
+{
+	char *input = *inputp;
+	unsigned int major, minor;
+	struct gendisk *disk;
+	int key_len, part;
+
+	if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2)
+		return ERR_PTR(-EINVAL);
+
+	input += key_len;
+	if (!isspace(*input))
+		return ERR_PTR(-EINVAL);
+	input = skip_spaces(input);
+
+	disk = get_gendisk(MKDEV(major, minor), &part);
+	if (!disk)
+		return ERR_PTR(-ENODEV);
+	if (part) {
+		put_disk_and_module(disk);
+		return ERR_PTR(-ENODEV);
+	}
+
+	*inputp = input;
+	return disk;
+}
+
+/**
+ * blkg_conf_prep - parse and prepare for per-blkg config update
  * @blkcg: target block cgroup
  * @pol: target policy
  * @input: input string
@@ -772,25 +810,11 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 	struct gendisk *disk;
 	struct request_queue *q;
 	struct blkcg_gq *blkg;
-	unsigned int major, minor;
-	int key_len, part, ret;
-	char *body;
-
-	if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2)
-		return -EINVAL;
-
-	body = input + key_len;
-	if (!isspace(*body))
-		return -EINVAL;
-	body = skip_spaces(body);
+	int ret;
 
-	disk = get_gendisk(MKDEV(major, minor), &part);
-	if (!disk)
-		return -ENODEV;
-	if (part) {
-		ret = -ENODEV;
-		goto fail;
-	}
+	disk = blkcg_conf_get_disk(&input);
+	if (IS_ERR(disk))
+		return PTR_ERR(disk);
 
 	q = disk->queue;
 
@@ -856,7 +880,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 success:
 	ctx->disk = disk;
 	ctx->blkg = blkg;
-	ctx->body = body;
+	ctx->body = input;
 	return 0;
 
 fail_unlock:
@@ -876,6 +900,7 @@ fail:
 	}
 	return ret;
 }
+EXPORT_SYMBOL_GPL(blkg_conf_prep);
 
 /**
  * blkg_conf_finish - finish up per-blkg config update
@@ -891,6 +916,7 @@ void blkg_conf_finish(struct blkg_conf_ctx *ctx)
 	rcu_read_unlock();
 	put_disk_and_module(ctx->disk);
 }
+EXPORT_SYMBOL_GPL(blkg_conf_finish);
 
 static int blkcg_print_stat(struct seq_file *sf, void *v)
 {
@@ -1346,7 +1372,7 @@ int blkcg_activate_policy(struct request_queue *q,
 		blk_mq_freeze_queue(q);
 pd_prealloc:
 	if (!pd_prealloc) {
-		pd_prealloc = pol->pd_alloc_fn(GFP_KERNEL, q->node);
+		pd_prealloc = pol->pd_alloc_fn(GFP_KERNEL, q, &blkcg_root);
 		if (!pd_prealloc) {
 			ret = -ENOMEM;
 			goto out_bypass_end;
@@ -1362,7 +1388,7 @@ pd_prealloc:
 		if (blkg->pd[pol->plid])
 			continue;
 
-		pd = pol->pd_alloc_fn(GFP_NOWAIT | __GFP_NOWARN, q->node);
+		pd = pol->pd_alloc_fn(GFP_NOWAIT | __GFP_NOWARN, q, &blkcg_root);
 		if (!pd)
 			swap(pd, pd_prealloc);
 		if (!pd) {
@@ -1475,7 +1501,8 @@ int blkcg_policy_register(struct blkcg_policy *pol)
 			blkcg->cpd[pol->plid] = cpd;
 			cpd->blkcg = blkcg;
 			cpd->plid = pol->plid;
-			pol->cpd_init_fn(cpd);
+			if (pol->cpd_init_fn)
+				pol->cpd_init_fn(cpd);
 		}
 	}