[PATCH 5/5] Staging: hv: storvsc: Implement per device memory pools

["K. Y. Srinivasan" <kys@microsoft.com>]

The current code implemented a per-HBA memory pool mechanism. For IDE disks
managed by this driver, there is a one to one correspondance between the
block device and the associated virtual HBA and since currently only IDE devices
can be the boot device, this addressed the deadlock issues that were raised during
the review process. This patch implements a per-lun memory pool mechanism.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/staging/hv/storvsc_drv.c |  106 ++++++++++++++++++++++----------------
 1 files changed, 62 insertions(+), 44 deletions(-)

diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index c22de06..18f8771 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -285,10 +285,13 @@ struct storvsc_device {
 	struct hv_storvsc_request reset_request;
 };
 
-struct hv_host_device {
-	struct hv_device *dev;
+struct stor_mem_pools {
 	struct kmem_cache *request_pool;
 	mempool_t *request_mempool;
+};
+
+struct hv_host_device {
+	struct hv_device *dev;
 	unsigned int port;
 	unsigned char path;
 	unsigned char target;
@@ -790,7 +793,48 @@ static void storvsc_get_ide_info(struct hv_device *dev, int *target, int *path)
 
 static int storvsc_device_alloc(struct scsi_device *sdevice)
 {
+	struct stor_mem_pools *memp;
+	int number = STORVSC_MIN_BUF_NR;
+
+	memp = kzalloc(sizeof(struct stor_mem_pools), GFP_KERNEL);
+	if (!memp)
+		return -ENOMEM;
+
+	memp->request_pool =
+		kmem_cache_create(dev_name(&sdevice->sdev_dev),
+				sizeof(struct storvsc_cmd_request), 0,
+				SLAB_HWCACHE_ALIGN, NULL);
+
+	if (!memp->request_pool)
+		goto err0;
+
+	memp->request_mempool = mempool_create(number, mempool_alloc_slab,
+						mempool_free_slab,
+						memp->request_pool);
+
+	if (!memp->request_mempool)
+		goto err1;
+
+	sdevice->hostdata = memp;
+
 	return 0;
+
+err1:
+	kmem_cache_destroy(memp->request_pool);
+
+err0:
+	kfree(memp);
+	return -ENOMEM;
+}
+
+static void storvsc_device_destroy(struct scsi_device *sdevice)
+{
+	struct stor_mem_pools *memp = sdevice->hostdata;
+
+	mempool_destroy(memp->request_mempool);
+	kmem_cache_destroy(memp->request_pool);
+	kfree(memp);
+	sdevice->hostdata = NULL;
 }
 
 static int storvsc_device_configure(struct scsi_device *sdevice)
@@ -1031,19 +1075,13 @@ static int storvsc_remove(struct hv_device *dev)
 {
 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
 	struct Scsi_Host *host = stor_device->host;
-	struct hv_host_device *host_dev = shost_priv(host);
 
 	scsi_remove_host(host);
 
 	scsi_host_put(host);
 
 	storvsc_dev_remove(dev);
-	if (host_dev->request_pool) {
-		mempool_destroy(host_dev->request_mempool);
-		kmem_cache_destroy(host_dev->request_pool);
-		host_dev->request_pool = NULL;
-		host_dev->request_mempool = NULL;
-	}
+
 	return 0;
 }
 
@@ -1139,6 +1177,7 @@ static void storvsc_command_completion(struct hv_storvsc_request *request)
 	struct scsi_sense_hdr sense_hdr;
 	struct vmscsi_request *vm_srb;
 	struct storvsc_scan_work *wrk;
+	struct stor_mem_pools *memp = scmnd->device->hostdata;
 
 	vm_srb = &request->vstor_packet.vm_srb;
 	if (cmd_request->bounce_sgl_count) {
@@ -1201,7 +1240,7 @@ static void storvsc_command_completion(struct hv_storvsc_request *request)
 
 	scsi_done_fn(scmnd);
 
-	mempool_free(cmd_request, host_dev->request_mempool);
+	mempool_free(cmd_request, memp->request_mempool);
 }
 
 static bool storvsc_check_scsi_cmd(struct scsi_cmnd *scmnd)
@@ -1236,6 +1275,7 @@ 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 stor_mem_pools *memp = scmnd->device->hostdata;
 
 	if (storvsc_check_scsi_cmd(scmnd) == false) {
 		scmnd->scsi_done(scmnd);
@@ -1253,7 +1293,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 
 	request_size = sizeof(struct storvsc_cmd_request);
 
-	cmd_request = mempool_alloc(host_dev->request_mempool,
+	cmd_request = mempool_alloc(memp->request_mempool,
 				       GFP_ATOMIC);
 	if (!cmd_request)
 		return SCSI_MLQUEUE_DEVICE_BUSY;
@@ -1312,7 +1352,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 			if (!cmd_request->bounce_sgl) {
 				scmnd->host_scribble = NULL;
 				mempool_free(cmd_request,
-						host_dev->request_mempool);
+						memp->request_mempool);
 
 				return SCSI_MLQUEUE_HOST_BUSY;
 			}
@@ -1354,7 +1394,7 @@ retry_request:
 			destroy_bounce_buffer(cmd_request->bounce_sgl,
 					cmd_request->bounce_sgl_count);
 
-		mempool_free(cmd_request, host_dev->request_mempool);
+		mempool_free(cmd_request, memp->request_mempool);
 
 		scmnd->host_scribble = NULL;
 
@@ -1372,6 +1412,7 @@ static struct scsi_host_template scsi_driver = {
 	.queuecommand =		storvsc_queuecommand,
 	.eh_host_reset_handler =	storvsc_host_reset_handler,
 	.slave_alloc =		storvsc_device_alloc,
+	.slave_destroy =	storvsc_device_destroy,
 	.slave_configure =	storvsc_device_configure,
 	.cmd_per_lun =		1,
 	/* 64 max_queue * 1 target */
@@ -1413,7 +1454,6 @@ static int storvsc_probe(struct hv_device *device,
 			const struct hv_vmbus_device_id *dev_id)
 {
 	int ret;
-	int number = STORVSC_MIN_BUF_NR;
 	struct Scsi_Host *host;
 	struct hv_host_device *host_dev;
 	bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
@@ -1432,29 +1472,11 @@ static int storvsc_probe(struct hv_device *device,
 	host_dev->port = host->host_no;
 	host_dev->dev = device;
 
-	host_dev->request_pool =
-				kmem_cache_create(dev_name(&device->device),
-					sizeof(struct storvsc_cmd_request), 0,
-					SLAB_HWCACHE_ALIGN, NULL);
-
-	if (!host_dev->request_pool) {
-		scsi_host_put(host);
-		return -ENOMEM;
-	}
-
-	host_dev->request_mempool = mempool_create(number, mempool_alloc_slab,
-						mempool_free_slab,
-						host_dev->request_pool);
-
-	if (!host_dev->request_mempool) {
-		ret = -ENOMEM;
-		goto err_out0;
-	}
 
 	stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
 	if (!stor_device) {
 		ret = -ENOMEM;
-		goto err_out1;
+		goto err_out0;
 	}
 
 	stor_device->destroy = false;
@@ -1466,7 +1488,7 @@ static int storvsc_probe(struct hv_device *device,
 	stor_device->port_number = host->host_no;
 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
 	if (ret)
-		goto err_out2;
+		goto err_out1;
 
 	if (dev_is_ide)
 		storvsc_get_ide_info(device, &target, &path);
@@ -1486,7 +1508,7 @@ static int storvsc_probe(struct hv_device *device,
 	/* Register the HBA and start the scsi bus scan */
 	ret = scsi_add_host(host, &device->device);
 	if (ret != 0)
-		goto err_out3;
+		goto err_out2;
 
 	if (!dev_is_ide) {
 		scsi_scan_host(host);
@@ -1495,28 +1517,24 @@ static int storvsc_probe(struct hv_device *device,
 	ret = scsi_add_device(host, 0, target, 0);
 	if (ret) {
 		scsi_remove_host(host);
-		goto err_out3;
+		goto err_out2;
 	}
 	return 0;
 
-err_out3:
+err_out2:
 	/*
 	 * Once we have connected with the host, we would need to
 	 * to invoke storvsc_dev_remove() to rollback this state and
 	 * this call also frees up the stor_device; hence the jump around
-	 * err_out2 label.
+	 * err_out1 label.
 	 */
 	storvsc_dev_remove(device);
-	goto err_out1;
-
-err_out2:
-	kfree(stor_device);
+	goto err_out0;
 
 err_out1:
-	mempool_destroy(host_dev->request_mempool);
+	kfree(stor_device);
 
 err_out0:
-	kmem_cache_destroy(host_dev->request_pool);
 	scsi_host_put(host);
 	return ret;
 }
-- 
1.7.4.1