scsi: smartpqi: enhance kdump

constrain resource usage during kdump to avoid kdump failures
Reviewed-by: Scott Benesh <scott.benesh@microsemi.com>
Signed-off-by: Kevin Barnett <kevin.barnett@microsemi.com>
Signed-off-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/smartpqi/smartpqi.h

@@ -687,7 +687,9 @@ struct pqi_config_table_heartbeat {
 };
 
 #define PQI_MAX_OUTSTANDING_REQUESTS		((u32)~0)
+#define PQI_MAX_OUTSTANDING_REQUESTS_KDUMP	32
 #define PQI_MAX_TRANSFER_SIZE			(4 * 1024U * 1024U)
+#define PQI_MAX_TRANSFER_SIZE_KDUMP		(512 * 1024U)
 
 #define RAID_MAP_MAX_ENTRIES		1024
 

drivers/scsi/smartpqi/smartpqi_init.c

@@ -4353,8 +4353,12 @@ static void pqi_calculate_io_resources(struct pqi_ctrl_info *ctrl_info)
 	ctrl_info->error_buffer_length =
 		ctrl_info->max_io_slots * PQI_ERROR_BUFFER_ELEMENT_LENGTH;
 
-	max_transfer_size =
-		min(ctrl_info->max_transfer_size, PQI_MAX_TRANSFER_SIZE);
+	if (reset_devices)
+		max_transfer_size = min(ctrl_info->max_transfer_size,
+			PQI_MAX_TRANSFER_SIZE_KDUMP);
+	else
+		max_transfer_size = min(ctrl_info->max_transfer_size,
+			PQI_MAX_TRANSFER_SIZE);
 
 	max_sg_entries = max_transfer_size / PAGE_SIZE;
 
@@ -4374,12 +4378,16 @@ static void pqi_calculate_io_resources(struct pqi_ctrl_info *ctrl_info)
 
 static void pqi_calculate_queue_resources(struct pqi_ctrl_info *ctrl_info)
 {
-	int num_cpus;
-	int max_queue_groups;
 	int num_queue_groups;
 	u16 num_elements_per_iq;
 	u16 num_elements_per_oq;
 
+	if (reset_devices) {
+		num_queue_groups = 1;
+	} else {
+		int num_cpus;
+		int max_queue_groups;
+
 		max_queue_groups = min(ctrl_info->max_inbound_queues / 2,
 			ctrl_info->max_outbound_queues - 1);
 		max_queue_groups = min(max_queue_groups, PQI_MAX_QUEUE_GROUPS);
@@ -4387,6 +4395,7 @@ static void pqi_calculate_queue_resources(struct pqi_ctrl_info *ctrl_info)
 		num_cpus = num_online_cpus();
 		num_queue_groups = min(num_cpus, ctrl_info->max_msix_vectors);
 		num_queue_groups = min(num_queue_groups, max_queue_groups);
+	}
 
 	ctrl_info->num_queue_groups = num_queue_groups;
 	ctrl_info->max_hw_queue_index = num_queue_groups - 1;
@@ -5827,9 +5836,17 @@ static int pqi_ctrl_init(struct pqi_ctrl_info *ctrl_info)
 		return rc;
 	}
 
-	if (ctrl_info->max_outstanding_requests > PQI_MAX_OUTSTANDING_REQUESTS)
+	if (reset_devices) {
+		if (ctrl_info->max_outstanding_requests >
+			PQI_MAX_OUTSTANDING_REQUESTS_KDUMP)
+			ctrl_info->max_outstanding_requests =
+					PQI_MAX_OUTSTANDING_REQUESTS_KDUMP;
+	} else {
+		if (ctrl_info->max_outstanding_requests >
+			PQI_MAX_OUTSTANDING_REQUESTS)
 			ctrl_info->max_outstanding_requests =
 					PQI_MAX_OUTSTANDING_REQUESTS;
+	}
 
 	pqi_calculate_io_resources(ctrl_info);
 
@@ -7110,4 +7127,6 @@ static void __attribute__((unused)) verify_structures(void)
 		PQI_QUEUE_ELEMENT_LENGTH_ALIGNMENT != 0);
 
 	BUILD_BUG_ON(PQI_RESERVED_IO_SLOTS >= PQI_MAX_OUTSTANDING_REQUESTS);
+	BUILD_BUG_ON(PQI_RESERVED_IO_SLOTS >=
+		PQI_MAX_OUTSTANDING_REQUESTS_KDUMP);
 }