[SCSI] megaraid_sas: Add input parameter for max_sectors
Driver add the input parameters support for max_sectors for megaraid
sas gen2 chip. Customer can set the max_sectors support to 1MB for
gen2 chip during the driver load.
Signed-off-by Bo Yang <bo.yang@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index 09a455d..41ffc20 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -56,6 +56,15 @@
MODULE_PARM_DESC(poll_mode_io,
"Complete cmds from IO path, (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");
+
MODULE_LICENSE("GPL");
MODULE_VERSION(MEGASAS_VERSION);
MODULE_AUTHOR("megaraidlinux@lsi.com");
@@ -3586,6 +3595,27 @@
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) {
+ if (((instance->pdev->device ==
+ PCI_DEVICE_ID_LSI_SAS1078GEN2) ||
+ (instance->pdev->device ==
+ PCI_DEVICE_ID_LSI_SAS0079GEN2)) &&
+ (max_sectors <= MEGASAS_MAX_SECTORS)) {
+ instance->max_sectors_per_req = max_sectors;
+ } else {
+ printk(KERN_INFO "megasas: max_sectors should be > 0"
+ "and <= %d (or < 1MB for GEN2 controller)\n",
+ instance->max_sectors_per_req);
+ }
+ }
+ }
+
host->max_sectors = instance->max_sectors_per_req;
host->cmd_per_lun = 128;
host->max_channel = MEGASAS_MAX_CHANNELS - 1;
