mmc: core: Fix deadlock when the CONFIG_MMC_UNSAFE_RESUME is not defined

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>
Acked-by: Ulf Hansson <ulf.hansson@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

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;
 		}