From fc8ebd01deeb12728c83381f6ec923e4a192ffd3 Mon Sep 17 00:00:00 2001 From: "Maciej S. Szmigiero" Date: Wed, 15 Aug 2018 23:56:45 +0200 Subject: [PATCH] block, bfq: return nbytes and not zero from struct cftype .write() method The value that struct cftype .write() method returns is then directly returned to userspace as the value returned by write() syscall, so it should be the number of bytes actually written (or consumed) and not zero. Returning zero from write() syscall makes programs like /bin/echo or bash spin. Signed-off-by: Maciej S. Szmigiero Fixes: e21b7a0b9887 ("block, bfq: add full hierarchical scheduling and cgroups support") Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe --- block/bfq-cgroup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index a9e8633..58c6efa 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -913,7 +913,8 @@ static ssize_t bfq_io_set_weight(struct kernfs_open_file *of, if (ret) return ret; - return bfq_io_set_weight_legacy(of_css(of), NULL, weight); + ret = bfq_io_set_weight_legacy(of_css(of), NULL, weight); + return ret ?: nbytes; } #ifdef CONFIG_DEBUG_BLK_CGROUP -- 2.7.4