[PATCH] storvsc: set cmd_info and avoid mempool allocation for per-cmd data

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <***@lst.de>
---
drivers/scsi/storvsc_drv.c | 118 +++------------------------------------------
1 file changed, 7 insertions(+), 111 deletions(-)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 733e5f7..0ddb0b6 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -32,7 +32,6 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/hyperv.h>
-#include <linux/mempool.h>
#include <linux/blkdev.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
@@ -309,14 +308,6 @@ enum storvsc_request_type {
* This is the end of Protocol specific defines.
*/

-
-/*
- * We setup a mempool to allocate request structures for this driver
- * on a per-lun basis. The following define specifies the number of
- * elements in the pool.
- */
-
-#define STORVSC_MIN_BUF_NR 64
static int storvsc_ringbuffer_size = (20 * PAGE_SIZE);

module_param(storvsc_ringbuffer_size, int, S_IRUGO);
@@ -346,7 +337,6 @@ static void storvsc_on_channel_callback(void *context);
#define STORVSC_IDE_MAX_CHANNELS 1

struct storvsc_cmd_request {
- struct list_head entry;
struct scsi_cmnd *cmd;

unsigned int bounce_sgl_count;
@@ -357,7 +347,6 @@ struct storvsc_cmd_request {
/* Synchronize the request/response if needed */
struct completion wait_event;

- unsigned char *sense_buffer;
struct hv_multipage_buffer data_buffer;
struct vstor_packet vstor_packet;
};
@@ -389,11 +378,6 @@ struct storvsc_device {
struct storvsc_cmd_request reset_request;
};

-struct stor_mem_pools {
- struct kmem_cache *request_pool;
- mempool_t *request_mempool;
-};
-
struct hv_host_device {
struct hv_device *dev;
unsigned int port;
@@ -1070,10 +1054,8 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
{
struct scsi_cmnd *scmnd = cmd_request->cmd;
struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
- void (*scsi_done_fn)(struct scsi_cmnd *);
struct scsi_sense_hdr sense_hdr;
struct vmscsi_request *vm_srb;
- struct stor_mem_pools *memp = scmnd->device->hostdata;
struct Scsi_Host *host;
struct storvsc_device *stor_dev;
struct hv_device *dev = host_dev->dev;
@@ -1108,14 +1090,7 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
cmd_request->data_buffer.len -
vm_srb->data_transfer_length);

- scsi_done_fn = scmnd->scsi_done;
-
- scmnd->host_scribble = NULL;
- scmnd->scsi_done = NULL;
-
- scsi_done_fn(scmnd);
-
- mempool_free(cmd_request, memp->request_mempool);
+ scmnd->scsi_done(scmnd);
}

static void storvsc_on_io_completion(struct hv_device *device,
@@ -1159,7 +1134,7 @@ static void storvsc_on_io_completion(struct hv_device *device,
SRB_STATUS_AUTOSENSE_VALID) {
/* autosense data available */

- memcpy(request->sense_buffer,
+ memcpy(request->cmd->sense_buffer,
vstor_packet->vm_srb.sense_data,
vstor_packet->vm_srb.sense_info_length);

@@ -1377,55 +1352,6 @@ static int storvsc_do_io(struct hv_device *device,
return ret;
}

-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;
-
- if (!memp)
- return;
-
- 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)
{
scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
@@ -1561,13 +1487,11 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
int ret;
struct hv_host_device *host_dev = shost_priv(host);
struct hv_device *dev = host_dev->dev;
- struct storvsc_cmd_request *cmd_request;
- unsigned int request_size = 0;
+ struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
int i;
struct scatterlist *sgl;
unsigned int sg_count = 0;
struct vmscsi_request *vm_srb;
- struct stor_mem_pools *memp = scmnd->device->hostdata;

if (vmstor_current_major <= VMSTOR_WIN8_MAJOR) {
/*
@@ -1584,25 +1508,9 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
}
}

- request_size = sizeof(struct storvsc_cmd_request);
-
- cmd_request = mempool_alloc(memp->request_mempool,
- GFP_ATOMIC);
-
- /*
- * We might be invoked in an interrupt context; hence
- * mempool_alloc() can fail.
- */
- if (!cmd_request)
- return SCSI_MLQUEUE_DEVICE_BUSY;
-
- memset(cmd_request, 0, sizeof(struct storvsc_cmd_request));
-
/* Setup the cmd request */
cmd_request->cmd = scmnd;

- scmnd->host_scribble = (unsigned char *)cmd_request;
-
vm_srb = &cmd_request->vstor_packet.vm_srb;
vm_srb->win8_extension.time_out_value = 60;

@@ -1637,9 +1545,6 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)

memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);

- cmd_request->sense_buffer = scmnd->sense_buffer;
-
-
cmd_request->data_buffer.len = scsi_bufflen(scmnd);
if (scsi_sg_count(scmnd)) {
sgl = (struct scatterlist *)scsi_sglist(scmnd);
@@ -1651,10 +1556,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
create_bounce_buffer(sgl, scsi_sg_count(scmnd),
scsi_bufflen(scmnd),
vm_srb->data_in);
- if (!cmd_request->bounce_sgl) {
- ret = SCSI_MLQUEUE_HOST_BUSY;
- goto queue_error;
- }
+ if (!cmd_request->bounce_sgl)
+ return SCSI_MLQUEUE_HOST_BUSY;

cmd_request->bounce_sgl_count =
ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
@@ -1692,28 +1595,21 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
destroy_bounce_buffer(cmd_request->bounce_sgl,
cmd_request->bounce_sgl_count);

- ret = SCSI_MLQUEUE_DEVICE_BUSY;
- goto queue_error;
+ return SCSI_MLQUEUE_DEVICE_BUSY;
}
}

return 0;
-
-queue_error:
- mempool_free(cmd_request, memp->request_mempool);
- scmnd->host_scribble = NULL;
- return ret;
}

static struct scsi_host_template scsi_driver = {
.module = THIS_MODULE,
.name = "storvsc_host_t",
+ .cmd_size = sizeof(struct storvsc_cmd_request),
.bios_param = storvsc_get_chs,
.queuecommand = storvsc_queuecommand,
.eh_host_reset_handler = storvsc_host_reset_handler,
.eh_timed_out = storvsc_eh_timed_out,
- .slave_alloc = storvsc_device_alloc,
- .slave_destroy = storvsc_device_destroy,
.slave_configure = storvsc_device_configure,
.cmd_per_lun = 255,
.can_queue = STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,

[KY Srinivasan]

-----Original Message-----
Sent: Sunday, October 19, 2014 8:18 AM
To: KY Srinivasan
Subject: hyperv storvsc cleanup / optimization
Hi KY,
can you throw the patch below into your testing rig? It converts the storvsc
driver to use our new cmd_size field, and thus avoids all the slab/mepool
infrastructure for private data in the driver.

Will do.

K. Y

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