scsi: storvsc: Size the queue depth based on the ringbuffer size
Size the queue depth based on the ringbuffer size. Also accommodate for the
fact that we could have multiple channels (ringbuffers) per adaptor.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 27fe850..7f569f9 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -309,10 +309,15 @@
*/
static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
+static u32 max_outstanding_req_per_channel;
+
+static int storvsc_vcpus_per_sub_channel = 4;
module_param(storvsc_ringbuffer_size, int, S_IRUGO);
MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
+module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
+MODULE_PARM_DESC(vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
/*
* Timeout in seconds for all devices managed by this driver.
*/
@@ -320,7 +325,6 @@
static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
-#define STORVSC_MAX_IO_REQUESTS 200
static void storvsc_on_channel_callback(void *context);
@@ -1376,7 +1380,6 @@
static int storvsc_device_configure(struct scsi_device *sdevice)
{
- scsi_change_queue_depth(sdevice, STORVSC_MAX_IO_REQUESTS);
blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
@@ -1646,7 +1649,6 @@
.eh_timed_out = storvsc_eh_timed_out,
.slave_configure = storvsc_device_configure,
.cmd_per_lun = 255,
- .can_queue = STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
.this_id = -1,
/* no use setting to 0 since ll_blk_rw reset it to 1 */
/* currently 32 */
@@ -1686,6 +1688,7 @@
const struct hv_vmbus_device_id *dev_id)
{
int ret;
+ int num_cpus = num_online_cpus();
struct Scsi_Host *host;
struct hv_host_device *host_dev;
bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
@@ -1694,6 +1697,7 @@
int max_luns_per_target;
int max_targets;
int max_channels;
+ int max_sub_channels = 0;
/*
* Based on the windows host we are running on,
@@ -1719,12 +1723,18 @@
max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
max_targets = STORVSC_MAX_TARGETS;
max_channels = STORVSC_MAX_CHANNELS;
+ /*
+ * On Windows8 and above, we support sub-channels for storage.
+ * The number of sub-channels offerred is based on the number of
+ * VCPUs in the guest.
+ */
+ max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
break;
}
- if (dev_id->driver_data == SFC_GUID)
- scsi_driver.can_queue = (STORVSC_MAX_IO_REQUESTS *
- STORVSC_FC_MAX_TARGETS);
+ scsi_driver.can_queue = (max_outstanding_req_per_channel *
+ (max_sub_channels + 1));
+
host = scsi_host_alloc(&scsi_driver,
sizeof(struct hv_host_device));
if (!host)
@@ -1837,7 +1847,6 @@
static int __init storvsc_drv_init(void)
{
- u32 max_outstanding_req_per_channel;
/*
* Divide the ring buffer data size (which is 1 page less
@@ -1852,10 +1861,6 @@
vmscsi_size_delta,
sizeof(u64)));
- if (max_outstanding_req_per_channel <
- STORVSC_MAX_IO_REQUESTS)
- return -EINVAL;
-
return vmbus_driver_register(&storvsc_drv);
}