Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0db13fc2 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Chris Ball
Browse files

mmc: fix a deadlock between system suspend and MMC block IO 



Performing MMC block IO with simultaneous STR can lead to a deadlock: the
mmc_pm_notify() function claims the host and then calls bus .remove()
method, which lands in mmc_blk_remove(), which calls mmc_blk_remove_req()
then it goes to -> mmc_cleanup_queue() -> kthread_stop(), which waits for
the mmc-block thread to stop. If the mmc-block thread at that time is
processing block requests, it will also try to claim the host in
mmc_blk_issue_rq() and block there. This patch fixes the problem by
calling .remove() before claiming the host.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: default avatarArindam Nath <arindam.nath@amd.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 3abc1e80

drivers/mmc/core/core.c

+6 −3
Original line number Diff line number Diff line
@@ -2175,6 +2175,7 @@ void mmc_stop_host(struct mmc_host *host) 


	mmc_bus_get(host);

	if (host->bus_ops && !host->bus_dead) {

		/* Calling bus_ops->remove() with a claimed host can deadlock */

		if (host->bus_ops->remove)

			host->bus_ops->remove(host);
@@ -2398,7 +2399,9 @@ int mmc_suspend_host(struct mmc_host *host) 
			if (err == -ENOSYS || !host->bus_ops->resume) {

				/*

				 * We simply "remove" the card in this case.

				 * It will be redetected on resume.

				 * It will be redetected on resume.  (Calling

				 * bus_ops->remove() with a claimed host can

				 * deadlock.)

				 */

				if (host->bus_ops->remove)

					host->bus_ops->remove(host);
@@ -2491,11 +2494,11 @@ int mmc_pm_notify(struct notifier_block *notify_block, 
		if (!host->bus_ops || host->bus_ops->suspend)

			break;



		mmc_claim_host(host);



		/* Calling bus_ops->remove() with a claimed host can deadlock */

		if (host->bus_ops->remove)

			host->bus_ops->remove(host);



		mmc_claim_host(host);

		mmc_detach_bus(host);

		mmc_power_off(host);

		mmc_release_host(host);