2 files changed, 61 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 4a602853a98e..4362dcde74af 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -16,6 +16,7 @@
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/delay.h>
+#include <linux/hardirq.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_dbg.h>
@@ -2248,3 +2249,61 @@ scsi_target_unblock(struct device *dev)
                 device_for_each_child(dev, NULL, target_unblock);
 }
 EXPORT_SYMBOL_GPL(scsi_target_unblock);
+
+
+struct work_queue_work {
+        struct work_struct      work;
+        void                    (*fn)(void *);
+        void                    *data;
+};
+
+static void execute_in_process_context_work(void *data)
+{
+        void (*fn)(void *data);
+        struct work_queue_work *wqw = data;
+
+        fn = wqw->fn;
+        data = wqw->data;
+
+        kfree(wqw);
+
+        fn(data);
+}
+
+/**
+ * scsi_execute_in_process_context - reliably execute the routine with user context
+ * @fn:         the function to execute
+ * @data:       data to pass to the function
+ *
+ * Executes the function immediately if process context is available,
+ * otherwise schedules the function for delayed execution.
+ *
+ * Returns:     0 - function was executed
+ *              1 - function was scheduled for execution
+ *              <0 - error
+ */
+int scsi_execute_in_process_context(void (*fn)(void *data), void *data)
+{
+        struct work_queue_work *wqw;
+
+        if (!in_interrupt()) {
+                fn(data);
+                return 0;
+        }
+
+        wqw = kmalloc(sizeof(struct work_queue_work), GFP_ATOMIC);
+
+        if (unlikely(!wqw)) {
+                printk(KERN_ERR "Failed to allocate memory\n");
+                WARN_ON(1);
+                return -ENOMEM;
+        }
+
+        INIT_WORK(&wqw->work, execute_in_process_context_work, wqw);
+        wqw->fn = fn;
+        wqw->data = data;
+        schedule_work(&wqw->work);
+
+        return 1;
+}
+EXPORT_SYMBOL_GPL(scsi_execute_in_process_context);
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index c60b8ff2f5e4..9c331258bc27 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -433,4 +433,6 @@ struct scsi_lun {
 /* Used to obtain the PCI location of a device */
 #define SCSI_IOCTL_GET_PCI              0x5387
 
+int scsi_execute_in_process_context(void (*fn)(void *data), void *data);
+
 #endif /* _SCSI_SCSI_H */