[PATCH 3/8] scsi: megaraid_sas - add module param max_sectors, cmd_per_lun

[bo yang <bo.yang@lsi.com>]

Adding module parameters to configure max sectors per request & # of cmds per lun.

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

---
 drivers/scsi/megaraid/megaraid_sas.c |   94 ++++++++++++++++++++++++-
 drivers/scsi/megaraid/megaraid_sas.h |    2
 2 files changed, 94 insertions(+), 2 deletions(-)

diff -uprN 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	2007-09-26 13:30:36.000000000 -0700
+++ linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.c	2007-09-27 20:37:11.000000000 -0700
@@ -62,6 +62,23 @@ MODULE_PARM_DESC(fast_load,
 	"megasas: Faster loading of the driver, skips physical devices! \
 	 (default = 0)");
 
+/*
+ * Number of sectors per IO command will be set in megasas_init_mfi
+ * if user does not provide
+ */
+static unsigned int max_sectors;
+module_param_named(max_sectors, max_sectors, int, 0);
+MODULE_PARM_DESC(max_sectors,
+	"Maximum number of sectors per IO command");
+
+/*
+ * Number of cmds per logical unit
+ */
+static unsigned int cmd_per_lun = MEGASAS_DEFAULT_CMD_PER_LUN;
+module_param_named(cmd_per_lun, cmd_per_lun, int, 0);
+MODULE_PARM_DESC(cmd_per_lun,
+	"Maximum number of commands per logical unit (default=128)");
+
 MODULE_LICENSE("GPL");
 MODULE_VERSION(MEGASAS_VERSION);
 MODULE_AUTHOR("megaraidlinux@lsi.com");
@@ -2301,6 +2318,31 @@ static int megasas_start_aen(struct mega
 				    class_locale.word);
 }
 
+static ssize_t
+sysfs_max_sectors_read(struct kobject *kobj,
+			struct bin_attribute *bin_attr,
+			char *buf, loff_t off, size_t count)
+{
+	struct Scsi_Host *host = class_to_shost(container_of(kobj,
+					struct class_device, kobj));
+	struct megasas_instance *instance =
+				(struct megasas_instance *)host->hostdata;
+
+	count = sprintf(buf, "%u\n", instance->max_sectors_per_req);
+
+	return count+1;
+}
+
+static struct bin_attribute sysfs_max_sectors_attr = {
+	.attr = {
+		.name = "max_sectors",
+		.mode = S_IRUSR|S_IRGRP|S_IROTH,
+		.owner = THIS_MODULE,
+	},
+	.size = 7,
+	.read = sysfs_max_sectors_read,
+};
+
 /**
  * megasas_io_attach -	Attaches this driver to SCSI mid-layer
  * @instance:		Adapter soft state
@@ -2308,17 +2350,48 @@ static int megasas_start_aen(struct mega
 static int megasas_io_attach(struct megasas_instance *instance)
 {
 	struct Scsi_Host *host = instance->host;
+	int error;
 
 	/*
-	 * Export parameters required by SCSI mid-layer
+	 * Export host parameters required by SCSI
+	 * mid-layer
 	 */
 	host->irq = instance->pdev->irq;
 	host->unique_id = instance->unique_id;
 	host->can_queue = instance->max_fw_cmds - MEGASAS_INT_CMDS;
 	host->this_id = instance->init_id;
 	host->sg_tablesize = instance->max_num_sge;
+
+	/*
+	 * Check if the module parameter value for max_sectors can be used
+	 */
+	if (max_sectors && max_sectors <= instance->max_sectors_per_req)
+		instance->max_sectors_per_req = max_sectors;
+	else {
+		if (max_sectors)
+			printk(KERN_INFO
+				"megasas: max_sectors should be > 0 and"
+				"<= %d\n",
+				instance->max_sectors_per_req);
+	}
+
 	host->max_sectors = instance->max_sectors_per_req;
-	host->cmd_per_lun = 128;
+
+	/*
+	 * Check if the module parameter value for cmd_per_lun can be used
+	 */
+	instance->cmd_per_lun = MEGASAS_DEFAULT_CMD_PER_LUN;
+	if (cmd_per_lun && cmd_per_lun <= MEGASAS_DEFAULT_CMD_PER_LUN)
+		instance->cmd_per_lun = cmd_per_lun;
+	else
+		printk(KERN_INFO "megasas: cmd_per_lun should be > 0 and"
+			"<= %d\n", MEGASAS_DEFAULT_CMD_PER_LUN);
+
+	host->cmd_per_lun = instance->cmd_per_lun;
+
+	printk(KERN_DEBUG "megasas: max_sectors : 0x%x, cmd_per_lun : 0x%x\n",
+			instance->max_sectors_per_req, instance->cmd_per_lun);
+
 	host->max_channel = MEGASAS_MAX_CHANNELS - 1;
 	host->max_id = MEGASAS_MAX_DEV_PER_CHANNEL;
 	host->max_lun = MEGASAS_MAX_LUN;
@@ -2333,10 +2406,25 @@ static int megasas_io_attach(struct mega
 	}
 
 	/*
+	 * Create sysfs entries for module paramaters
+	 */
+	error = sysfs_create_bin_file(&instance->host->shost_classdev.kobj,
+			&sysfs_max_sectors_attr);
+	if (error) {
+		printk(KERN_INFO "megasas: Error in creating the sysfs entry"
+				" max_sectors.\n");
+		goto out_remove_host;
+	}
+
+	/*
 	 * Trigger SCSI to scan our drives
 	 */
 	scsi_scan_host(host);
 	return 0;
+
+out_remove_host:
+	scsi_remove_host(host);
+	return error;
 }
 
 static int
@@ -2750,6 +2838,8 @@ static void megasas_detach_one(struct pc
 	instance = pci_get_drvdata(pdev);
 	host = instance->host;
 
+	sysfs_remove_bin_file(&host->shost_classdev.kobj,
+				&sysfs_max_sectors_attr);
 	scsi_remove_host(instance->host);
 	megasas_flush_cache(instance);
 	megasas_shutdown_controller(instance, MR_DCMD_CTRL_SHUTDOWN);
diff -uprN linux-2.6.22_orig/drivers/scsi/megaraid/megaraid_sas.h linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.h
--- linux-2.6.22_orig/drivers/scsi/megaraid/megaraid_sas.h	2007-09-26 13:27:59.000000000 -0700
+++ linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.h	2007-09-26 13:27:31.000000000 -0700
@@ -537,6 +537,7 @@ struct megasas_ctrl_info {
 #define MEGASAS_DEFAULT_INIT_ID			-1
 #define MEGASAS_MAX_LUN				8
 #define MEGASAS_MAX_LD				64
+#define MEGASAS_DEFAULT_CMD_PER_LUN		128
 
 #define MEGASAS_DBG_LVL				1
 
@@ -1080,6 +1081,7 @@ struct megasas_instance {
 	u16 max_num_sge;
 	u16 max_fw_cmds;
 	u32 max_sectors_per_req;
+	u32 cmd_per_lun;
 
 	struct megasas_cmd **cmd_list;
 	struct list_head cmd_pool;


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