linux-kernel - Re: [PATCH 2/3] tcm: Add VARIABLE_LENGTH_CMD support w/ XDWRITE_READ

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Date:	Sun, 19 Sep 2010 14:17:58 +0200
From:	Boaz Harrosh <bharrosh@...asas.com>
To:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
CC:	linux-scsi <linux-scsi@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	James Bottomley <James.Bottomley@...e.de>,
	Mike Christie <michaelc@...wisc.edu>,
	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
	Hannes Reinecke <hare@...e.de>,
	Konrad Rzeszutek Wilk <konrad@...nok.org>,
	Douglas Gilbert <dgilbert@...erlog.com>,
	Joe Eykholt <jeykholt@...co.com>
Subject: Re: [PATCH 2/3] tcm: Add VARIABLE_LENGTH_CMD support w/ XDWRITE_READ_32
 emulation

On 09/17/2010 07:34 AM, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@...ux-iscsi.org>
> 
> This patch updates transport_generic_cmd_sequencer() to properly support
> VARIABLE_LENGTH_CMD w/ service action XDWRITE_READ_32 emulation.  This
> patch follows the original XDWRITE_READ_10 patch, and uses the new 32-byte
> CDB extraction callers from commit 39a347ca2d88.  Note this patch uses the
> same transport_xor_callback() assignment callback as XDWRITE_READ_10.
> 
> Also note that this patch enforces the following > TCM_MAX_COMMAND_SIZE check
> for VARIABLE_LENGTH_CMD CDBs in transport_generic_cmd_sequencer():
> 
> 	<SNIP>
>         /*
>          * Check the additional CDB length (+ 8 bytes for header) does
>          * not exceed our TCM_MAX_COMMAND_SIZE.
>          */
>          if ((cdb[7] + 8) > TCM_MAX_COMMAND_SIZE) {
>                 printk(KERN_INFO "Only %u-byte extended CDBs currently"
>                          " supported for VARIABLE_LENGTH_CMD, received:"
>                          " %d for service action: 0x%04x\n",
>                          TCM_MAX_COMMAND_SIZE, cdb[7], service_action);
>                 return TGCS_INVALID_CDB_FIELD;
>          }
> 	<SNIP>
> 
> Signed-off-by: Nicholas A. Bellinger <nab@...ux-iscsi.org>
> ---
>  drivers/target/target_core_transport.c |   50 +++++++++++++++++++++++++++----
>  1 files changed, 43 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
> index a3016f7..a20a4a9 100644
> --- a/drivers/target/target_core_transport.c
> +++ b/drivers/target/target_core_transport.c
> @@ -5401,6 +5401,7 @@ static int transport_generic_cmd_sequencer(
>  	struct se_subsystem_dev *su_dev = dev->se_sub_dev;
>  	int ret, sector_ret = 0;
>  	u32 sectors = 0, size = 0, pr_reg_type = 0;
> +	u16 service_action;
>  	u8 alua_ascq = 0;
>  	/*
>  	 * Check for an existing UNIT ATTENTION condition
> @@ -5572,6 +5573,48 @@ static int transport_generic_cmd_sequencer(
>  		T_TASK(cmd)->t_tasks_fua = (cdb[1] & 0x8);
>  		ret = TGCS_DATA_SG_IO_CDB;
>  		break;
> +	case VARIABLE_LENGTH_CMD:
> +		SET_GENERIC_TRANSPORT_FUNCTIONS(cmd);
> +		service_action = (cdb[8] << 8) | cdb[9];
get_unaligned_be16
> +		/*
> +		 * Check the additional CDB length (+ 8 bytes for header) does
> +		 * not exceed our TCM_MAX_COMMAND_SIZE.
> +		 */
> +		if ((cdb[7] + 8) > TCM_MAX_COMMAND_SIZE) {

		scsi_varlen_cdb_length(cdb)
it's in scsi.h

> +			printk(KERN_INFO "Only %u-byte extended CDBs currently"
> +				" supported for VARIABLE_LENGTH_CMD, received:"
> +				" %d for service action: 0x%04x\n",
> +				TCM_MAX_COMMAND_SIZE, cdb[7], service_action);
> +			return TGCS_INVALID_CDB_FIELD;
> +		}
> +		switch (service_action) {
> +		case 0x0007: /* XDWRITE_READ_32 */

Is it about time to define all these service_action codes. I have the OSD defines
in an OSD header. So I'm GUILTY just as much.
(but I do have an enum in a public header, at least)


> +			sectors = transport_get_sectors_32(cdb, cmd, &sector_ret);
> +			if (sector_ret)
> +				return TGCS_UNSUPPORTED_CDB;
> +			size = transport_get_size(sectors, cdb, cmd);
> +			transport_dev_get_mem_SG(cmd->se_orig_obj_ptr, cmd);
> +			transport_get_maps(cmd);
> +			/*
> +			 * Use WRITE_32 and READ_32 opcodes for the emulated
> +			 * XDWRITE_READ_32 logic.
> +			 */
> +			cmd->transport_split_cdb = &split_cdb_XX_32;
> +			cmd->transport_get_long_lba = &transport_lba_64_ext;
> +			/*
> +			 * Setup BIDI XOR callback to be run during
> +			 * transport_generic_complete_ok()
> +			 */
> +			cmd->transport_complete_callback = &transport_xor_callback;
> +			T_TASK(cmd)->t_tasks_fua = (cdb[10] & 0x8);
> +			ret = TGCS_DATA_SG_IO_CDB;	
> +			break;
> +		default:
> +			printk(KERN_ERR "VARIABLE_LENGTH_CMD service action"
> +				" 0x%04x not supported\n", service_action);
> +			return TGCS_UNSUPPORTED_CDB;
> +		}
> +		break;
>  	case 0xa3:
>  		SET_GENERIC_TRANSPORT_FUNCTIONS(cmd);
>  		if (TRANSPORT(dev)->get_device_type(dev) != TYPE_ROM) {
> @@ -5747,13 +5790,6 @@ static int transport_generic_cmd_sequencer(
>  		transport_get_maps(cmd);
>  		ret = TGCS_CONTROL_NONSG_IO_CDB;
>  		break;
> -	case VARIABLE_LENGTH_CMD:
> -		SET_GENERIC_TRANSPORT_FUNCTIONS(cmd);
> -		size = (cdb[10] << 8) | cdb[11];
> -		transport_dev_get_mem_buf(cmd->se_orig_obj_ptr, cmd);
> -		transport_get_maps(cmd);
> -		ret = TGCS_CONTROL_NONSG_IO_CDB;
> -		break;
>  	case RECEIVE_DIAGNOSTIC:
>  	case SEND_DIAGNOSTIC:
>  		SET_GENERIC_TRANSPORT_FUNCTIONS(cmd);

Thanks
Boaz
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