1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 7161f913de14..ddd1b83f44d4 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -33,6 +33,8 @@
 #include <linux/platform_device.h>
 #include <linux/mutex.h>
 #include <linux/completion.h>
+#include <linux/hardirq.h>
+#include <linux/irqflags.h>
 #include <asm/uaccess.h>
 #include <asm/semaphore.h>
 
@@ -861,7 +863,15 @@ int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num)
                 }
 #endif
 
-                mutex_lock_nested(&adap->bus_lock, adap->level);
+                if (in_atomic() || irqs_disabled()) {
+                        ret = mutex_trylock(&adap->bus_lock);
+                        if (!ret)
+                                /* I2C activity is ongoing. */
+                                return -EAGAIN;
+                } else {
+                        mutex_lock_nested(&adap->bus_lock, adap->level);
+                }
+
                 ret = adap->algo->master_xfer(adap,msgs,num);
                 mutex_unlock(&adap->bus_lock);