PATCH 2/4] scsi: megaraid_sas -- add module param fast_load

PATCH 2/4] scsi: megaraid_sas -- add module param fast_load

[linux-box]

Driver will skip physical devices scan for the first time if the fast_load is set

Signed-off-by: Bo Yang <bo.yang@lsi.com>

---
 drivers/scsi/megaraid/megaraid_sas.c |   69 +++++++++++++++++++------
 1 files changed, 55 insertions(+), 14 deletions(-)

diff -rupN linux-2.6.22_orig/drivers/scsi/megaraid/megaraid_sas.c linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.c
--- linux-2.6.22_orig/drivers/scsi/megaraid/megaraid_sas.c	2007-07-23 23:02:18.000000000 -0400
+++ linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.c	2007-08-14 21:48:00.075930672 -0400
@@ -46,6 +46,22 @@
 #include <scsi/scsi_host.h>
 #include "megaraid_sas.h"
 
+/*
+ * Module parameters
+ */
+
+/*
+ * Fast driver load option, skip scanning for physical devices during
+ * load.  This would result in physical devices being skipped during
+ * driver load time. These can be later added though,
+ * using /proc/scsi/scsi
+ */
+static unsigned int fast_load;
+module_param_named(fast_load, fast_load, int, 0);
+MODULE_PARM_DESC(fast_load,
+	"megasas: Faster loading of the driver, skips physical devices! \
+	 (default = 0)");
+
 MODULE_LICENSE("GPL");
 MODULE_VERSION(MEGASAS_VERSION);
 MODULE_AUTHOR("megaraidlinux@lsi.com");
@@ -1094,6 +1110,44 @@ megasas_service_aen(struct megasas_insta
 	megasas_return_cmd(instance, cmd);
 }
 
+static struct megasas_instance *megasas_lookup_instance(u16 host_no)
+{
+	int i;
+
+	for (i = 0; i < megasas_mgmt_info.max_index; i++) {
+		if ((megasas_mgmt_info.instance[i]) &&
+			(megasas_mgmt_info.instance[i]->host->host_no
+			== host_no))
+			return megasas_mgmt_info.instance[i];
+	}
+
+	return NULL;
+}
+
+static int megasas_slave_alloc(struct scsi_device *sdev)
+{
+	struct megasas_instance *instance;
+	int tmp_fastload = fast_load;
+
+	instance = megasas_lookup_instance(sdev->host->host_no);
+
+	if (tmp_fastload && sdev->channel < MEGASAS_MAX_PD_CHANNELS) {
+		if ((sdev->id == MEGASAS_MAX_DEV_PER_CHANNEL -1) &&
+			(sdev->channel == MEGASAS_MAX_PD_CHANNELS - 1)) {
+
+		/*
+		 * If fast load option was set and scan for last device is
+		 * over, reset the fast_load flag so that during a possible
+		 * next scan, devices can be made available
+		 */
+			fast_load = 0;
+		}
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
 /*
  * Scsi host template for megaraid_sas driver
  */
@@ -1103,6 +1157,7 @@ static struct scsi_host_template megasas
 	.name = "LSI Logic SAS based MegaRAID driver",
 	.proc_name = "megaraid_sas",
 	.slave_configure = megasas_slave_configure,
+	.slave_alloc = megasas_slave_alloc,
 	.queuecommand = megasas_queue_command,
 	.eh_device_reset_handler = megasas_reset_device,
 	.eh_bus_reset_handler = megasas_reset_bus_host,
@@ -2970,20 +3025,6 @@ megasas_mgmt_fw_ioctl(struct megasas_ins
 	return error;
 }
 
-static struct megasas_instance *megasas_lookup_instance(u16 host_no)
-{
-	int i;
-
-	for (i = 0; i < megasas_mgmt_info.max_index; i++) {
-
-		if ((megasas_mgmt_info.instance[i]) &&
-		    (megasas_mgmt_info.instance[i]->host->host_no == host_no))
-			return megasas_mgmt_info.instance[i];
-	}
-
-	return NULL;
-}
-
 static int megasas_mgmt_ioctl_fw(struct file *file, unsigned long arg)
 {
 	struct megasas_iocpacket __user *user_ioc =

Re: PATCH 2/4] scsi: megaraid_sas -- add module param fast_load

[Andrew Morton]

On Tue, 11 Sep 2007 08:28:14 -0400 linux-box <bo.yang@lsi.com> wrote:

> Driver will skip physical devices scan for the first time if the fast_load is set

When preparing changelogs it is often good to describe _why_ the change is
being made, as well as what the change does.

It may be obvious to some people why users of this driver might want to use
this feature, but I don't have clue why you did this.