diff options
| author | Guennadi Liakhovetski <g.liakhovetski@gmx.de> | 2012-01-04 15:28:45 +0100 |
|---|---|---|
| committer | Chris Ball <cjb@laptop.org> | 2012-01-12 15:17:17 -0500 |
| commit | 0db13fc2abbb0b1a8d8efee20dfbd7f3c5d54022 (patch) | |
| tree | 9932b8a8bca14f536e9a23f905919d9ee9c1a10a | |
| parent | 3abc1e804253add41990cbe1461e79c1165108e0 (diff) | |
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: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Arindam Nath <arindam.nath@amd.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
| -rw-r--r-- | drivers/mmc/core/core.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 1da45e05132..bec0bf21c87 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -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); |