blk-mq: make sure that line break can be printed

commit d2c9be89f8ebe7ebcc97676ac40f8dec1cf9b43a upstream.

8962842ca5ab ("blk-mq: avoid sysfs buffer overflow with too many CPU cores")
avoids sysfs buffer overflow, and reserves one character for line break.
However, the last snprintf() doesn't get correct 'size' parameter passed
in, so fixed it.

Fixes: 8962842ca5ab ("blk-mq: avoid sysfs buffer overflow with too many CPU cores")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 68996ef1d33945f6691e40b0de698f15356a4f66..a09ab0c3d074dcbefdcb9bf6caecd2806c7d688a 100644 (file)
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -183,7 +183,7 @@ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
                pos += ret;
        }
 
-       ret = snprintf(pos + page, size - pos, "\n");
+       ret = snprintf(pos + page, size + 1 - pos, "\n");
        return pos + ret;
 }