1 files changed, 25 insertions, 9 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index fb24a096dba..02f2b1871a3 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -461,16 +461,18 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
 	while (1) {
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		stop = abort ? atomic_read(abort) : 0;
-		if (stop || !host->claimed)
+		if (stop || !host->claimed || host->claimer == current)
 			break;
 		spin_unlock_irqrestore(&host->lock, flags);
 		schedule();
 		spin_lock_irqsave(&host->lock, flags);
 	}
 	set_current_state(TASK_RUNNING);
-	if (!stop)
+	if (!stop) {
 		host->claimed = 1;
-	else
+		host->claimer = current;
+		host->claim_cnt += 1;
+	} else
 		wake_up(&host->wq);
 	spin_unlock_irqrestore(&host->lock, flags);
 	remove_wait_queue(&host->wq, &wait);
@@ -481,29 +483,43 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort)
 
 EXPORT_SYMBOL(__mmc_claim_host);
 
-static int mmc_try_claim_host(struct mmc_host *host)
+/**
+ *	mmc_try_claim_host - try exclusively to claim a host
+ *	@host: mmc host to claim
+ *
+ *	Returns %1 if the host is claimed, %0 otherwise.
+ */
+int mmc_try_claim_host(struct mmc_host *host)
 {
 	int claimed_host = 0;
 	unsigned long flags;
 
 	spin_lock_irqsave(&host->lock, flags);
-	if (!host->claimed) {
+	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);
 	return claimed_host;
 }
+EXPORT_SYMBOL(mmc_try_claim_host);
 
 static void mmc_do_release_host(struct mmc_host *host)
 {
 	unsigned long flags;
 
 	spin_lock_irqsave(&host->lock, flags);
-	host->claimed = 0;
-	spin_unlock_irqrestore(&host->lock, flags);
-
-	wake_up(&host->wq);
+	if (--host->claim_cnt) {
+		/* Release for nested claim */
+		spin_unlock_irqrestore(&host->lock, flags);
+	} else {
+		host->claimed = 0;
+		host->claimer = NULL;
+		spin_unlock_irqrestore(&host->lock, flags);
+		wake_up(&host->wq);
+	}
 }
 
 void mmc_host_deeper_disable(struct work_struct *work)