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[157.230.128.187]) by smtp.gmail.com with ESMTPSA id u8sm11614115pjy.16.2020.04.19.12.45.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 19 Apr 2020 12:45:43 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id 082A04223D; Sun, 19 Apr 2020 19:45:39 +0000 (UTC) From: Luis Chamberlain To: axboe@kernel.dk, viro@zeniv.linux.org.uk, bvanassche@acm.org, gregkh@linuxfoundation.org, rostedt@goodmis.org, mingo@redhat.com, jack@suse.cz, ming.lei@redhat.com, nstange@suse.de, akpm@linux-foundation.org Cc: mhocko@suse.com, yukuai3@huawei.com, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Luis Chamberlain Subject: [PATCH v2 08/10] blktrace: add checks for created debugfs files on setup Date: Sun, 19 Apr 2020 19:45:27 +0000 Message-Id: <20200419194529.4872-9-mcgrof@kernel.org> X-Mailer: git-send-email 2.23.0.rc1 In-Reply-To: <20200419194529.4872-1-mcgrof@kernel.org> References: <20200419194529.4872-1-mcgrof@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Even though debugfs can be disabled, enabling BLK_DEV_IO_TRACE will select DEBUG_FS, and blktrace exposes an API which userspace uses relying on certain files created in debugfs. If files are not created blktrace will not work correctly, so we do want to ensure that a blktrace setup creates these files properly, and otherwise inform userspace. Signed-off-by: Luis Chamberlain --- kernel/trace/blktrace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 9cc0153849c3..fc32a8665ce8 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -552,17 +552,19 @@ static int blk_trace_create_debugfs_files(struct bl= k_user_trace_setup *buts, struct dentry *dir, struct blk_trace *bt) { - int ret =3D -EIO; - bt->dropped_file =3D debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops); + if (!bt->dropped_file) + return -ENOMEM; =20 bt->msg_file =3D debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fop= s); + if (!bt->msg_file) + return -ENOMEM; =20 bt->rchan =3D relay_open("trace", dir, buts->buf_size, buts->buf_nr, &blk_relay_callbacks, bt); if (!bt->rchan) - return ret; + return -EIO; =20 return 0; } --=20 2.25.1