Merge "mmc: core: Retry claim host in mmc_sd_detect"

3 files changed, 44 insertions, 1 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index f79e8377a2ee..5396e1d00178 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2114,6 +2114,38 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
 EXPORT_SYMBOL(__mmc_claim_host);
 
 /**
+ *     mmc_try_claim_host - try exclusively to claim a host
+ *        and keep trying for given time, with a gap of 10ms
+ *     @host: mmc host to claim
+ *     @dealy_ms: delay in ms
+ *
+ *     Returns %1 if the host is claimed, %0 otherwise.
+ */
+int mmc_try_claim_host(struct mmc_host *host, unsigned int delay_ms)
+{
+	int claimed_host = 0;
+	unsigned long flags;
+	int retry_cnt = delay_ms/10;
+
+	do {
+		spin_lock_irqsave(&host->lock, flags);
+		if (!host->claimed || host->claimer == current) {
+			host->claimed = 1;
+			host->claimer = current;
+			host->claim_cnt += 1;
+			claimed_host = 1;
+		}
+		spin_unlock_irqrestore(&host->lock, flags);
+		if (!claimed_host)
+			mmc_delay(10);
+	} while (!claimed_host && retry_cnt--);
+	if (host->ops->enable && claimed_host && host->claim_cnt == 1)
+		host->ops->enable(host);
+	return claimed_host;
+}
+EXPORT_SYMBOL(mmc_try_claim_host);
+
+/**
  *	mmc_release_host - release a host
  *	@host: mmc host to release
  *
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 7e7d7eb4da2a..ec5ce79e84e7 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1147,7 +1147,17 @@ static void mmc_sd_detect(struct mmc_host *host)
 	BUG_ON(!host);
 	BUG_ON(!host->card);
 
-	mmc_get_card(host->card);
+	/*
+	 * Try to acquire claim host. If failed to get the lock in 2 sec,
+	 * just return; This is to ensure that when this call is invoked
+	 * due to pm_suspend, not to block suspend for longer duration.
+	 */
+	pm_runtime_get_sync(&host->card->dev);
+	if (!mmc_try_claim_host(host, 2000)) {
+		pm_runtime_mark_last_busy(&host->card->dev);
+		pm_runtime_put_autosuspend(&host->card->dev);
+		return;
+	}
 
 	/*
 	 * Just check if our card has been removed.
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 55a30d685226..1068953943d8 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -203,6 +203,7 @@ extern unsigned int mmc_align_data_size(struct mmc_card *, unsigned int);
 
 extern int __mmc_claim_host(struct mmc_host *host, atomic_t *abort);
 extern void mmc_release_host(struct mmc_host *host);
+extern int mmc_try_claim_host(struct mmc_host *host, unsigned int delay);
 
 extern void mmc_get_card(struct mmc_card *card);
 extern void mmc_put_card(struct mmc_card *card);