linux-kernel - Re: [PATCH 4/4] scsi: storvsc: Tighten up the interrupt path

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Date:	Fri, 11 Dec 2015 10:12:45 +0100
From:	Johannes Thumshirn <jthumshirn@...e.de>
To:	"K. Y. Srinivasan" <kys@...rosoft.com>
Cc:	gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	devel@...uxdriverproject.org, ohering@...e.com,
	jbottomley@...allels.com, hch@...radead.org,
	linux-scsi@...r.kernel.org, apw@...onical.com, vkuznets@...hat.com,
	jasowang@...hat.com, martin.petersen@...cle.com
Subject: Re: [PATCH 4/4] scsi: storvsc: Tighten up the interrupt path

On Thu, Dec 10, 2015 at 04:14:20PM -0800, K. Y. Srinivasan wrote:
> On the interrupt path, we repeatedly establish the pointer to the
> storvsc_device. Fix this.
> 
> Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
> Reviewed-by: Long Li <longli@...rosoft.com>
> Tested-by: Alex Ng <alexng@...rosoft.com>
> ---
>  drivers/scsi/storvsc_drv.c |   23 ++++++++---------------
>  1 files changed, 8 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 6f18e94..8ba9908 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -958,19 +958,16 @@ static void storvsc_handle_error(struct vmscsi_request *vm_srb,
>  }
>  
>  
> -static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
> +static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
> +				       struct storvsc_device *stor_dev)
>  {
>  	struct scsi_cmnd *scmnd = cmd_request->cmd;
> -	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
>  	struct scsi_sense_hdr sense_hdr;
>  	struct vmscsi_request *vm_srb;
>  	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;
>  
>  	vm_srb = &cmd_request->vstor_packet.vm_srb;
> @@ -1000,14 +997,13 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
>  		kfree(payload);
>  }
>  
> -static void storvsc_on_io_completion(struct hv_device *device,
> +static void storvsc_on_io_completion(struct storvsc_device *stor_device,
>  				  struct vstor_packet *vstor_packet,
>  				  struct storvsc_cmd_request *request)
>  {
> -	struct storvsc_device *stor_device;
>  	struct vstor_packet *stor_pkt;
> +	struct hv_device *device = stor_device->device;
>  
> -	stor_device = hv_get_drvdata(device);
>  	stor_pkt = &request->vstor_packet;
>  
>  	/*
> @@ -1062,7 +1058,7 @@ static void storvsc_on_io_completion(struct hv_device *device,
>  	stor_pkt->vm_srb.data_transfer_length =
>  	vstor_packet->vm_srb.data_transfer_length;
>  
> -	storvsc_command_completion(request);
> +	storvsc_command_completion(request, stor_device);
>  
>  	if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
>  		stor_device->drain_notify)
> @@ -1071,21 +1067,19 @@ static void storvsc_on_io_completion(struct hv_device *device,
>  
>  }
>  
> -static void storvsc_on_receive(struct hv_device *device,
> +static void storvsc_on_receive(struct storvsc_device *stor_device,
>  			     struct vstor_packet *vstor_packet,
>  			     struct storvsc_cmd_request *request)
>  {
>  	struct storvsc_scan_work *work;
> -	struct storvsc_device *stor_device;
>  
>  	switch (vstor_packet->operation) {
>  	case VSTOR_OPERATION_COMPLETE_IO:
> -		storvsc_on_io_completion(device, vstor_packet, request);
> +		storvsc_on_io_completion(stor_device, vstor_packet, request);
>  		break;
>  
>  	case VSTOR_OPERATION_REMOVE_DEVICE:
>  	case VSTOR_OPERATION_ENUMERATE_BUS:
> -		stor_device = get_in_stor_device(device);
>  		work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
>  		if (!work)
>  			return;
> @@ -1096,7 +1090,6 @@ static void storvsc_on_receive(struct hv_device *device,
>  		break;
>  
>  	case VSTOR_OPERATION_FCHBA_DATA:
> -		stor_device = get_in_stor_device(device);
>  		cache_wwn(stor_device, vstor_packet);
>  		fc_host_node_name(stor_device->host) = stor_device->node_name;
>  		fc_host_port_name(stor_device->host) = stor_device->port_name;
> @@ -1144,7 +1137,7 @@ static void storvsc_on_channel_callback(void *context)
>  					vmscsi_size_delta));
>  				complete(&request->wait_event);
>  			} else {
> -				storvsc_on_receive(device,
> +				storvsc_on_receive(stor_device,
>  						(struct vstor_packet *)packet,
>  						request);
>  			}
> -- 
> 1.7.4.1
> 
> --
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Reviewed-by: Johannes Thumshirn <jthumshirn@...e.de>

-- 
Johannes Thumshirn                                          Storage
jthumshirn@...e.de                                +49 911 74053 689
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