[SCSI] megaraid_sas: add sysfs for AEN polling

update the sysfs parameter to tell application driver support AEN poll

Signed-off-by Bo Yang<bo.yang@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/megaraid/megaraid_sas.c

@@ -92,7 +92,7 @@ static DEFINE_MUTEX(megasas_async_queue_mutex);
 
 static int megasas_poll_wait_aen;
 static DECLARE_WAIT_QUEUE_HEAD(megasas_poll_wait);
-
+static u32 support_poll_for_event;
 static u32 megasas_dbg_lvl;
 
 /* define lock for aen poll */
@@ -3431,6 +3431,15 @@ megasas_sysfs_show_release_date(struct device_driver *dd, char *buf)
 static DRIVER_ATTR(release_date, S_IRUGO, megasas_sysfs_show_release_date,
 		   NULL);
 
+static ssize_t
+megasas_sysfs_show_support_poll_for_event(struct device_driver *dd, char *buf)
+{
+	return sprintf(buf, "%u\n", support_poll_for_event);
+}
+
+static DRIVER_ATTR(support_poll_for_event, S_IRUGO,
+			megasas_sysfs_show_support_poll_for_event, NULL);
+
 static ssize_t
 megasas_sysfs_show_dbg_lvl(struct device_driver *dd, char *buf)
 {
@@ -3522,6 +3531,8 @@ static int __init megasas_init(void)
 	printk(KERN_INFO "megasas: %s %s\n", MEGASAS_VERSION,
 	       MEGASAS_EXT_VERSION);
 
+	support_poll_for_event = 2;
+
 	memset(&megasas_mgmt_info, 0, sizeof(megasas_mgmt_info));
 
 	/*
@@ -3554,6 +3565,12 @@ static int __init megasas_init(void)
 				  &driver_attr_release_date);
 	if (rval)
 		goto err_dcf_rel_date;
+
+	rval = driver_create_file(&megasas_pci_driver.driver,
+				&driver_attr_support_poll_for_event);
+	if (rval)
+		goto err_dcf_support_poll_for_event;
+
 	rval = driver_create_file(&megasas_pci_driver.driver,
 				  &driver_attr_dbg_lvl);
 	if (rval)
@@ -3569,8 +3586,13 @@ static int __init megasas_init(void)
 	driver_remove_file(&megasas_pci_driver.driver,
 			   &driver_attr_dbg_lvl);
 err_dcf_dbg_lvl:
+	driver_remove_file(&megasas_pci_driver.driver,
+			&driver_attr_support_poll_for_event);
+
+err_dcf_support_poll_for_event:
 	driver_remove_file(&megasas_pci_driver.driver,
 			   &driver_attr_release_date);
+
 err_dcf_rel_date:
 	driver_remove_file(&megasas_pci_driver.driver, &driver_attr_version);
 err_dcf_attr_ver: