blk-mq: quiesce queue during switching io sched and updating nr_requests

[mirror_ubuntu-bionic-kernel.git] / block / blk-mq-sysfs.c

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index ff7c466e63c97797960b2811b7d75cfd17e3f48a..22b70c5dfe67edc2e4f524556a930d1b127a866d 100644 (file)
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -151,20 +151,25 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
 
 static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 {
+       const size_t size = PAGE_SIZE - 1;
        unsigned int i, first = 1;
-       ssize_t ret = 0;
+       int ret = 0, pos = 0;
 
        for_each_cpu(i, hctx->cpumask) {
                if (first)
-                       ret += sprintf(ret + page, "%u", i);
+                       ret = snprintf(pos + page, size - pos, "%u", i);
                else
-                       ret += sprintf(ret + page, ", %u", i);
+                       ret = snprintf(pos + page, size - pos, ", %u", i);
+
+               if (ret >= size - pos)
+                       break;
 
                first = 0;
+               pos += ret;
        }
 
-       ret += sprintf(ret + page, "\n");
-       return ret;
+       ret = snprintf(pos + page, size + 1 - pos, "\n");
+       return pos + ret;
 }
 
 static struct attribute *default_ctx_attrs[] = {