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SubjectRE: [PATCH] SCSI:STORVSC Use SCSI layer to allocate memory for per-command device request data
Date


> -----Original Message-----
> From: Christoph Hellwig [mailto:hch@lst.de]
> Sent: Monday, December 29, 2014 8:05 PM
> To: KY Srinivasan; Haiyang Zhang; JBottomley@parallels.com
> Cc: linux-scsi@vger.kernel.org; devel@linuxdriverproject.org; linux-
> kernel@vger.kernel.org; Long Li; Christoph Hellwig
> Subject: [PATCH] SCSI:STORVSC Use SCSI layer to allocate memory for per-
> command device request data
>
> STORVSC uses its own momory pool to manage device request data.
> However, SCSI layer already has a mechanisim for allocating additional
> memory for each command issued to device driver. This patch removes the
> memory pool in STORVSC and makes it use SCSI layer to allocate memory for
> device request data.
>
> Reviewed-by: Long Li <longli@microsoft.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Thanks Christoph.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>

> ---
> drivers/scsi/storvsc_drv.c | 119 +++------------------------------------------
> 1 file changed, 8 insertions(+), 111 deletions(-)
>
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index
> 4cff0dd..14ee98e 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; @@ -1109,14 +1091,7 @@
> 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, @@ -1160,7
> +1135,7 @@ 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);
>
> @@ -1378,55 +1353,6 @@ 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_change_queue_depth(sdevice, STORVSC_MAX_IO_REQUESTS);
> @@ -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) >>
> @@ -1692,27 +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,
> + .proc_name = "storvsc_host",
> .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,
> --
> 2.1.0



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