From: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Date: Tue, 29 Oct 2019 09:13:34 +0000 (+0000)
Subject: um-ubd: Entrust re-queue to the upper layers
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d848074b2f1eb11a38691285f7366bce83087014;p=linux.git

um-ubd: Entrust re-queue to the upper layers

Fixes crashes due to ubd requeue logic conflicting with the block-mq
logic. Crash is reproducible in 5.0 - 5.3.

Fixes: 53766defb8c8 ("um: Clean-up command processing in UML UBD driver")
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 612535cd97065..6627d7c30f370 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1403,8 +1403,12 @@ static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	spin_unlock_irq(&ubd_dev->lock);
 
-	if (ret < 0)
-		blk_mq_requeue_request(req, true);
+	if (ret < 0) {
+		if (ret == -ENOMEM)
+			res = BLK_STS_RESOURCE;
+		else
+			res = BLK_STS_DEV_RESOURCE;
+	}
 
 	return res;
 }