scsi: storvsc: Miscellaneous enhancements and fixes

index efc6e44..27fe850 100644
@@ -308,7 +308,7 @@ enum storvsc_request_type {
  * This is the end of Protocol specific defines.
  */
 
-static int storvsc_ringbuffer_size = (20 * PAGE_SIZE);
+static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
 
 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");

index 27fe850..7f569f9 100644
@@ -309,10 +309,15 @@ enum storvsc_request_type {
  */
 
 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 storvsc_timeout = 180;
 
 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_do_io(struct hv_device *device,
 
 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 @@ static struct scsi_host_template scsi_driver = {
 	.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 @@ static int storvsc_probe(struct hv_device *device,
 			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 @@ static int storvsc_probe(struct hv_device *device,
 	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 @@ static int storvsc_probe(struct hv_device *device,
 		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 struct hv_driver storvsc_drv = {
 
 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 @@ static int __init storvsc_drv_init(void)
 		vmscsi_size_delta,
 		sizeof(u64)));
 
-	if (max_outstanding_req_per_channel <
-	    STORVSC_MAX_IO_REQUESTS)
-		return -EINVAL;
-
 	return vmbus_driver_register(&storvsc_drv);
 }
 

index 7f569f9..0ba7f2c 100644
@@ -1362,7 +1362,7 @@ static int storvsc_do_io(struct hv_device *device,
 				vmscsi_size_delta),
 				(unsigned long)request);
 	} else {
-		ret = vmbus_sendpacket(device->channel, vstor_packet,
+		ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
 			       (sizeof(struct vstor_packet) -
 				vmscsi_size_delta),
 			       (unsigned long)request,

index 0ba7f2c..cdf048b 100644
@@ -377,6 +377,10 @@ struct storvsc_device {
 	unsigned char path_id;
 	unsigned char target_id;
 
+	/*
+	 * Max I/O, the device can support.
+	 */
+	u32   max_transfer_bytes;
 	/* Used for vsc/vsp channel reset process */
 	struct storvsc_cmd_request init_request;
 	struct storvsc_cmd_request reset_request;

@@ -974,6 +978,8 @@ static int storvsc_channel_init(struct hv_device *device)
 		    STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
 			process_sub_channels = true;
 	}
+	stor_device->max_transfer_bytes =
+		vstor_packet->storage_channel_properties.max_transfer_bytes;
 
 	memset(vstor_packet, 0, sizeof(struct vstor_packet));
 	vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;

index cdf048b..f8e4dd9 100644
@@ -754,21 +754,22 @@ static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 			if (bounce_sgl[j].length == PAGE_SIZE) {
 				/* full..move to next entry */
 				sg_kunmap_atomic(bounce_addr);
+				bounce_addr = 0;
 				j++;
+			}
 
-				/* if we need to use another bounce buffer */
-				if (srclen || i != orig_sgl_count - 1)
-					bounce_addr = sg_kmap_atomic(bounce_sgl,j);
+			/* if we need to use another bounce buffer */
+			if (srclen && bounce_addr == 0)
+				bounce_addr = sg_kmap_atomic(bounce_sgl, j);
 
-			} else if (srclen == 0 && i == orig_sgl_count - 1) {
-				/* unmap the last bounce that is < PAGE_SIZE */
-				sg_kunmap_atomic(bounce_addr);
-			}
 		}
 
 		sg_kunmap_atomic(src_addr - orig_sgl[i].offset);
 	}
 
+	if (bounce_addr)
+		sg_kunmap_atomic(bounce_addr);
+
 	local_irq_restore(flags);
 
 	return total_copied;

index f8e4dd9..4156e29 100644
@@ -626,19 +626,6 @@ cleanup:
 	return NULL;
 }
 
-/* Disgusting wrapper functions */
-static inline unsigned long sg_kmap_atomic(struct scatterlist *sgl, int idx)
-{
-	void *addr = kmap_atomic(sg_page(sgl + idx));
-	return (unsigned long)addr;
-}
-
-static inline void sg_kunmap_atomic(unsigned long addr)
-{
-	kunmap_atomic((void *)addr);
-}
-
-
 /* Assume the original sgl has enough room */
 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 					    struct scatterlist *bounce_sgl,

@@ -653,32 +640,38 @@ static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 	unsigned long bounce_addr = 0;
 	unsigned long dest_addr = 0;
 	unsigned long flags;
+	struct scatterlist *cur_dest_sgl;
+	struct scatterlist *cur_src_sgl;
 
 	local_irq_save(flags);
-
+	cur_dest_sgl = orig_sgl;
+	cur_src_sgl = bounce_sgl;
 	for (i = 0; i < orig_sgl_count; i++) {
-		dest_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
+		dest_addr = (unsigned long)
+				kmap_atomic(sg_page(cur_dest_sgl)) +
+				cur_dest_sgl->offset;
 		dest = dest_addr;
-		destlen = orig_sgl[i].length;
+		destlen = cur_dest_sgl->length;
 
 		if (bounce_addr == 0)
-			bounce_addr = sg_kmap_atomic(bounce_sgl,j);
+			bounce_addr = (unsigned long)kmap_atomic(
+							sg_page(cur_src_sgl));
 
 		while (destlen) {
-			src = bounce_addr + bounce_sgl[j].offset;
-			srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
+			src = bounce_addr + cur_src_sgl->offset;
+			srclen = cur_src_sgl->length - cur_src_sgl->offset;
 
 			copylen = min(srclen, destlen);
 			memcpy((void *)dest, (void *)src, copylen);
 
 			total_copied += copylen;
-			bounce_sgl[j].offset += copylen;
+			cur_src_sgl->offset += copylen;
 			destlen -= copylen;
 			dest += copylen;
 
-			if (bounce_sgl[j].offset == bounce_sgl[j].length) {
+			if (cur_src_sgl->offset == cur_src_sgl->length) {
 				/* full */
-				sg_kunmap_atomic(bounce_addr);
+				kunmap_atomic((void *)bounce_addr);
 				j++;
 
 				/*

@@ -692,21 +685,27 @@ static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 					/*
 					 * We are done; cleanup and return.
 					 */
-					sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
+					kunmap_atomic((void *)(dest_addr -
+						cur_dest_sgl->offset));
 					local_irq_restore(flags);
 					return total_copied;
 				}
 
 				/* if we need to use another bounce buffer */
-				if (destlen || i != orig_sgl_count - 1)
-					bounce_addr = sg_kmap_atomic(bounce_sgl,j);
+				if (destlen || i != orig_sgl_count - 1) {
+					cur_src_sgl = sg_next(cur_src_sgl);
+					bounce_addr = (unsigned long)
+							kmap_atomic(
+							sg_page(cur_src_sgl));
+				}
 			} else if (destlen == 0 && i == orig_sgl_count - 1) {
 				/* unmap the last bounce that is < PAGE_SIZE */
-				sg_kunmap_atomic(bounce_addr);
+				kunmap_atomic((void *)bounce_addr);
 			}
 		}
 
-		sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
+		kunmap_atomic((void *)(dest_addr - cur_dest_sgl->offset));
+		cur_dest_sgl = sg_next(cur_dest_sgl);
 	}
 
 	local_irq_restore(flags);

@@ -727,48 +726,61 @@ static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 	unsigned long bounce_addr = 0;
 	unsigned long src_addr = 0;
 	unsigned long flags;
+	struct scatterlist *cur_src_sgl;
+	struct scatterlist *cur_dest_sgl;
 
 	local_irq_save(flags);
 
+	cur_src_sgl = orig_sgl;
+	cur_dest_sgl = bounce_sgl;
+
 	for (i = 0; i < orig_sgl_count; i++) {
-		src_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
+		src_addr = (unsigned long)
+				kmap_atomic(sg_page(cur_src_sgl)) +
+				cur_src_sgl->offset;
 		src = src_addr;
-		srclen = orig_sgl[i].length;
+		srclen = cur_src_sgl->length;
 
 		if (bounce_addr == 0)
-			bounce_addr = sg_kmap_atomic(bounce_sgl,j);
+			bounce_addr = (unsigned long)
+					kmap_atomic(sg_page(cur_dest_sgl));
 
 		while (srclen) {
 			/* assume bounce offset always == 0 */
-			dest = bounce_addr + bounce_sgl[j].length;
-			destlen = PAGE_SIZE - bounce_sgl[j].length;
+			dest = bounce_addr + cur_dest_sgl->length;
+			destlen = PAGE_SIZE - cur_dest_sgl->length;
 
 			copylen = min(srclen, destlen);
 			memcpy((void *)dest, (void *)src, copylen);
 
 			total_copied += copylen;
-			bounce_sgl[j].length += copylen;
+			cur_dest_sgl->length += copylen;
 			srclen -= copylen;
 			src += copylen;
 
-			if (bounce_sgl[j].length == PAGE_SIZE) {
+			if (cur_dest_sgl->length == PAGE_SIZE) {
 				/* full..move to next entry */
-				sg_kunmap_atomic(bounce_addr);
+				kunmap_atomic((void *)bounce_addr);
 				bounce_addr = 0;
 				j++;
 			}
 
 			/* if we need to use another bounce buffer */
-			if (srclen && bounce_addr == 0)
-				bounce_addr = sg_kmap_atomic(bounce_sgl, j);
+			if (srclen && bounce_addr == 0) {
+				cur_dest_sgl = sg_next(cur_dest_sgl);
+				bounce_addr = (unsigned long)
+						kmap_atomic(
+						sg_page(cur_dest_sgl));
+			}
 
 		}
 
-		sg_kunmap_atomic(src_addr - orig_sgl[i].offset);
+		kunmap_atomic((void *)(src_addr - cur_src_sgl->offset));
+		cur_src_sgl = sg_next(cur_src_sgl);
 	}
 
 	if (bounce_addr)
-		sg_kunmap_atomic(bounce_addr);
+		kunmap_atomic((void *)bounce_addr);
 
 	local_irq_restore(flags);
 

@@ -1536,6 +1548,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 	struct scatterlist *sgl;
 	unsigned int sg_count = 0;
 	struct vmscsi_request *vm_srb;
+	struct scatterlist *cur_sgl;
 
 	if (vmstor_current_major <= VMSTOR_WIN8_MAJOR) {
 		/*

@@ -1617,10 +1630,12 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 		}
 
 		cmd_request->data_buffer.offset = sgl[0].offset;
-
-		for (i = 0; i < sg_count; i++)
+		cur_sgl = sgl;
+		for (i = 0; i < sg_count; i++) {
 			cmd_request->data_buffer.pfn_array[i] =
-				page_to_pfn(sg_page((&sgl[i])));
+				page_to_pfn(sg_page((cur_sgl)));
+			cur_sgl = sg_next(cur_sgl);
+		}
 
 	} else if (scsi_sglist(scmnd)) {
 		cmd_request->data_buffer.offset =

index 4156e29..d9dad90 100644
@@ -351,7 +351,10 @@ struct storvsc_cmd_request {
 	/* Synchronize the request/response if needed */
 	struct completion wait_event;
 
-	struct hv_multipage_buffer data_buffer;
+	struct vmbus_channel_packet_multipage_buffer mpb;
+	struct vmbus_packet_mpb_array *payload;
+	u32 payload_sz;
+
 	struct vstor_packet vstor_packet;
 };
 

@@ -1103,6 +1106,8 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
 	struct Scsi_Host *host;
 	struct storvsc_device *stor_dev;
 	struct hv_device *dev = host_dev->dev;
+	u32 payload_sz = cmd_request->payload_sz;
+	void *payload = cmd_request->payload;
 
 	stor_dev = get_in_stor_device(dev);
 	host = stor_dev->host;

@@ -1132,10 +1137,14 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
 					 sense_hdr.ascq);
 
 	scsi_set_resid(scmnd,
-		cmd_request->data_buffer.len -
+		cmd_request->payload->range.len -
 		vm_srb->data_transfer_length);
 
 	scmnd->scsi_done(scmnd);
+
+	if (payload_sz >
+		sizeof(struct vmbus_channel_packet_multipage_buffer))
+		kfree(payload);
 }
 
 static void storvsc_on_io_completion(struct hv_device *device,

@@ -1337,7 +1346,7 @@ static int storvsc_dev_remove(struct hv_device *device)
 }
 
 static int storvsc_do_io(struct hv_device *device,
-			      struct storvsc_cmd_request *request)
+			 struct storvsc_cmd_request *request)
 {
 	struct storvsc_device *stor_device;
 	struct vstor_packet *vstor_packet;

@@ -1369,13 +1378,14 @@ static int storvsc_do_io(struct hv_device *device,
 
 
 	vstor_packet->vm_srb.data_transfer_length =
-	request->data_buffer.len;
+	request->payload->range.len;
 
 	vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
 
-	if (request->data_buffer.len) {
-		ret = vmbus_sendpacket_multipagebuffer(outgoing_channel,
-				&request->data_buffer,
+	if (request->payload->range.len) {
+
+		ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
+				request->payload, request->payload_sz,
 				vstor_packet,
 				(sizeof(struct vstor_packet) -
 				vmscsi_size_delta),

@@ -1549,6 +1559,9 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 	unsigned int sg_count = 0;
 	struct vmscsi_request *vm_srb;
 	struct scatterlist *cur_sgl;
+	struct vmbus_packet_mpb_array  *payload;
+	u32 payload_sz;
+	u32 length;
 
 	if (vmstor_current_major <= VMSTOR_WIN8_MAJOR) {
 		/*

@@ -1602,48 +1615,71 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 
 	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
 
-	cmd_request->data_buffer.len = scsi_bufflen(scmnd);
-	if (scsi_sg_count(scmnd)) {
-		sgl = (struct scatterlist *)scsi_sglist(scmnd);
-		sg_count = scsi_sg_count(scmnd);
+	sgl = (struct scatterlist *)scsi_sglist(scmnd);
+	sg_count = scsi_sg_count(scmnd);
 
+	length = scsi_bufflen(scmnd);
+	payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
+	payload_sz = sizeof(cmd_request->mpb);
+
+	if (sg_count) {
 		/* check if we need to bounce the sgl */
 		if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
 			cmd_request->bounce_sgl =
-				create_bounce_buffer(sgl, scsi_sg_count(scmnd),
-						     scsi_bufflen(scmnd),
+				create_bounce_buffer(sgl, sg_count,
+						     length,
 						     vm_srb->data_in);
 			if (!cmd_request->bounce_sgl)
 				return SCSI_MLQUEUE_HOST_BUSY;
 
 			cmd_request->bounce_sgl_count =
-				ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
-					PAGE_SHIFT;
+				ALIGN(length, PAGE_SIZE) >> PAGE_SHIFT;
 
 			if (vm_srb->data_in == WRITE_TYPE)
 				copy_to_bounce_buffer(sgl,
-					cmd_request->bounce_sgl,
-					scsi_sg_count(scmnd));
+					cmd_request->bounce_sgl, sg_count);
 
 			sgl = cmd_request->bounce_sgl;
 			sg_count = cmd_request->bounce_sgl_count;
 		}
 
-		cmd_request->data_buffer.offset = sgl[0].offset;
+
+		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
+
+			payload_sz = (sg_count * sizeof(void *) +
+				      sizeof(struct vmbus_packet_mpb_array));
+			payload = kmalloc(payload_sz, GFP_ATOMIC);
+			if (!payload) {
+				if (cmd_request->bounce_sgl_count)
+					destroy_bounce_buffer(
+					cmd_request->bounce_sgl,
+					cmd_request->bounce_sgl_count);
+
+					return SCSI_MLQUEUE_DEVICE_BUSY;
+			}
+		}
+
+		payload->range.len = length;
+		payload->range.offset = sgl[0].offset;
+
 		cur_sgl = sgl;
 		for (i = 0; i < sg_count; i++) {
-			cmd_request->data_buffer.pfn_array[i] =
+			payload->range.pfn_array[i] =
 				page_to_pfn(sg_page((cur_sgl)));
 			cur_sgl = sg_next(cur_sgl);
 		}
 
 	} else if (scsi_sglist(scmnd)) {
-		cmd_request->data_buffer.offset =
+		payload->range.len = length;
+		payload->range.offset =
 			virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
-		cmd_request->data_buffer.pfn_array[0] =
+		payload->range.pfn_array[0] =
 			virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
 	}
 
+	cmd_request->payload = payload;
+	cmd_request->payload_sz = payload_sz;
+
 	/* Invokes the vsc to start an IO */
 	ret = storvsc_do_io(dev, cmd_request);
 

@@ -1672,10 +1708,7 @@ static struct scsi_host_template scsi_driver = {
 	.slave_configure =	storvsc_device_configure,
 	.cmd_per_lun =		255,
 	.this_id =		-1,
-	/* no use setting to 0 since ll_blk_rw reset it to 1 */
-	/* currently 32 */
-	.sg_tablesize =		MAX_MULTIPAGE_BUFFER_COUNT,
-	.use_clustering =	DISABLE_CLUSTERING,
+	.use_clustering =	ENABLE_CLUSTERING,
 	/* Make sure we dont get a sg segment crosses a page boundary */
 	.dma_boundary =		PAGE_SIZE-1,
 	.no_write_same =	1,

@@ -1812,6 +1845,12 @@ static int storvsc_probe(struct hv_device *device,
 	/* max cmd length */
 	host->max_cmd_len = STORVSC_MAX_CMD_LEN;
 
+	/*
+	 * set the table size based on the info we got
+	 * from the host.
+	 */
+	host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
+
 	/* Register the HBA and start the scsi bus scan */
 	ret = scsi_add_host(host, &device->device);
 	if (ret != 0)