3.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thorsten Knabe <linux@xxxxxxxxxxxxxxxxx>
commit 2a2361228c5e6d8c1733f00653481de918598e50 upstream.
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@xxxxxxxxxxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/um/drivers/ubd_kern.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1277,7 +1277,7 @@ static void do_ubd_request(struct reques
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 reques
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){
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html