block: really disable runtime-pm for blk-mq (Closes: #904441)

debian/changelog

@@ -5,6 +5,7 @@ linux (4.17.8-2) UNRELEASED; urgency=medium
     - gpu: host1x: Fix compiler errors by converting to dma_addr_t
   * [ia64] sched: Disable SCHED_STACK_END_CHECK (Closes: #905461)
   * mtd: powernv_flash: set of_node in mtd's dev (Closes: #904380)
+  * block: really disable runtime-pm for blk-mq (Closes: #904441)
 
  -- Ben Hutchings <ben@decadent.org.uk>  Sun, 05 Aug 2018 19:37:24 +0800
 

debian/patches/bugfix/all/block-really-disable-runtime-pm-for-blk-mq.patch

@@ -0,0 +1,44 @@
+From: Ming Lei <ming.lei@redhat.com>
+Subject: block: really disable runtime-pm for blk-mq
+Date: Mon, 30 Jul 2018 20:02:19 +0800
+Origin: https://patchwork.kernel.org/patch/10548975/
+Bug-Debian: https://bugs.debian.org/904441
+
+Runtime PM isn't ready for blk-mq yet, and commit 765e40b675a9 ("block:
+disable runtime-pm for blk-mq") tried to disable it. Unfortunately,
+it can't take effect in that way since user space still can switch
+it on via 'echo auto > /sys/block/sdN/device/power/control'.
+
+This patch disables runtime-pm for blk-mq really by pm_runtime_disable()
+and fixes all kinds of PM related kernel crash.
+
+Cc: Christoph Hellwig <hch@lst.de>
+Cc: Patrick Steinhardt <ps@pks.im>
+Cc: Bart Van Assche <Bart.VanAssche@wdc.com>
+Cc: Tomas Janousek <tomi@nomi.cz>
+Cc: Przemek Socha <soprwa@gmail.com>
+Cc: Alan Stern <stern@rowland.harvard.edu>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Ming Lei <ming.lei@redhat.com>
+Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+---
+ block/blk-core.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+--- a/block/blk-core.c
++++ b/block/blk-core.c
+@@ -3784,9 +3784,11 @@ EXPORT_SYMBOL(blk_finish_plug);
+  */
+ void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
+ {
+-	/* not support for RQF_PM and ->rpm_status in blk-mq yet */
+-	if (q->mq_ops)
++	/* Don't enable runtime PM for blk-mq until it is ready */
++	if (q->mq_ops) {
++		pm_runtime_disable(dev);
+ 		return;
++	}
+ 
+ 	q->dev = dev;
+ 	q->rpm_status = RPM_ACTIVE;

debian/patches/series

@@ -95,6 +95,7 @@ bugfix/all/kbuild-include-addtree-remove-quotes-before-matching-path.patch
 debian/revert-objtool-fix-config_stack_validation-y-warning.patch
 bugfix/all/i40e-build-for-64-bit-targets-only.patch
 bugfix/all/ib-fix-rdma_rxe-and-infiniband_rdmavt-dependencies-f.patch
+bugfix/all/block-really-disable-runtime-pm-for-blk-mq.patch
 
 # Miscellaneous features
 features/all/kbuild-add-build-salt-to-the-kernel-and-modules.patch