[PATCH V2] mmc: core: Fix deadlock when the CONFIG_MMC_UNSAFE_RESUME is not defined

Sujit Reddy Thumma
2011-11-23T03:13:27Z

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>

---
Changes in v2:
- Addressed review comment from Ulf Hansson.
---
drivers/mmc/core/core.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 271efea..950b97d 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2333,6 +2333,8 @@ int mmc_suspend_host(struct mmc_host *host)
mmc_poweroff_notify(host);
err = host->bus_ops->suspend(host);
}
+ mmc_do_release_host(host);
+
if (err == -ENOSYS || !host->bus_ops->resume) {
/*
* We simply "remove" the card in this case.
@@ -2347,7 +2349,6 @@ int mmc_suspend_host(struct mmc_host *host)
host->pm_flags = 0;
err = 0;
}
- 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.