[PATCH] mmc: core: Fix deadlock when the CONFIG_MMC_UNSAFE_RESUME is not defined

Sujit Reddy Thumma
2011-11-22T11:30:51Z

mmc_suspend_host() tries to claim host during suspend
and release it only when the bus suspend operation is
compeleted. If CONFIG_MMC_UNSAFE_RESUME is defined and
the host is flagged as removable, mmc_suspend_host()
tries to remove the card. In this process, the file system
sync can get blocked trying to acquire host which is already
claimed by mmc_suspend_host() causing deadlock.

Fix this deadlock by releasing host before ->remove() is called.

Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
---
drivers/mmc/core/core.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 271efea..8adbadf 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2338,6 +2338,7 @@ int mmc_suspend_host(struct mmc_host *host)
* We simply "remove" the card in this case.
* It will be redetected on resume.
*/
+ mmc_do_release_host(host);
if (host->bus_ops->remove)
host->bus_ops->remove(host);
mmc_claim_host(host);
@@ -2346,8 +2347,9 @@ int mmc_suspend_host(struct mmc_host *host)
mmc_release_host(host);
host->pm_flags = 0;
err = 0;
+ } else {
+ mmc_do_release_host(host);
}
- mmc_do_release_host(host);
} else {
err = -EBUSY;
}
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.