Messages in this thread Patch in this message | | | Date | Sat, 23 Aug 2014 15:47:38 +0200 | From | Thorsten Knabe <> | Subject | [PATCH] UML: UBD: Fix for processes stuck in D state forever in UserModeLinux |
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From: Thorsten Knabe <linux@thorsten-knabe.de>
UML: UBD: Fix for processes stuck in D state forever in UserModeLinux.
Starting with Linux 3.12 processes get stuck in D state forever in UserModeLinux under sync heavy workloads. This bug was introduced by commit 805f11a0d5 (um: ubd: Add REQ_FLUSH suppport). Fix bug by adding a check if FLUSH request was successfully submitted to the I/O thread and keeping the FLUSH request on the request queue on submission failures.
Fixes: 805f11a0d5 (um: ubd: Add REQ_FLUSH suppport) Signed-off-by: Thorsten Knabe <linux@thorsten-knabe.de> --- Patch applies to 3.16.1.
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index 3716e69..b7d2840 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -1277,7 +1277,7 @@ static void do_ubd_request(struct request_queue *q)
while(1){ struct ubd *dev = q->queuedata; - if(dev->end_sg == 0){ + if(dev->request == NULL){ struct request *req = blk_fetch_request(q); if(req == NULL) return; @@ -1299,7 +1299,8 @@ static void do_ubd_request(struct request_queue *q) return; } prepare_flush_request(req, io_req); - submit_request(io_req, dev); + if (submit_request(io_req, dev) == false) + return; }
while(dev->start_sg < dev->end_sg){
-- ___ | | / E-Mail: linux@thorsten-knabe.de |horsten |/\nabe WWW: http://linux.thorsten-knabe.de
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