Re: [PATCH 4/5] sd: Support disks formatted with DIF Type 2

[Boaz Harrosh <bharrosh@panasas.com>]

On 09/11/2009 10:20 PM, Martin K. Petersen wrote:
> Disks formatted with DIF Type 2 reject READ/WRITE 6/10/12/16 commands
> when protection is enabled.  Only the 32-byte variants are supported.
> 
> Implement support for issusing 32-byte READ/WRITE and enable Type 2
> drives in the protection type detection logic.
> 
> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Reviewed-by: Boaz Harrosh <bharrosh@panasas.com>

> ---
>  drivers/scsi/sd.c   |   80 ++++++++++++++++++++++++++++++++++++++++++++-------
>  drivers/scsi/sd.h   |    5 +++
>  include/scsi/scsi.h |    3 ++
>  3 files changed, 77 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 36e2333..d138e6b 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -116,6 +116,9 @@ static DEFINE_IDA(sd_index_ida);
>   * object after last put) */
>  static DEFINE_MUTEX(sd_ref_mutex);
>  
> +struct kmem_cache *sd_cdb_cache;
> +mempool_t *sd_cdb_pool;
> +
>  static const char *sd_cache_types[] = {
>  	"write through", "none", "write back",
>  	"write back, no read (daft)"
> @@ -413,6 +416,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
>  	sector_t threshold;
>  	unsigned int this_count = blk_rq_sectors(rq);
>  	int ret, host_dif;
> +	unsigned char protect;
>  
>  	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
>  		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
> @@ -545,13 +549,48 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
>  	/* Set RDPROTECT/WRPROTECT if disk is formatted with DIF */
>  	host_dif = scsi_host_dif_capable(sdp->host, sdkp->protection_type);
>  	if (host_dif)
> -		SCpnt->cmnd[1] = 1 << 5;
> +		protect = 1 << 5;
>  	else
> -		SCpnt->cmnd[1] = 0;
> +		protect = 0;
> +
> +	if (host_dif == SD_DIF_TYPE2_PROTECTION) {
> +		SCpnt->cmnd = mempool_alloc(sd_cdb_pool, GFP_ATOMIC);
> +
> +		if (unlikely(SCpnt->cmnd == NULL)) {
> +			ret = BLKPREP_DEFER;
> +			goto out;
> +		}
>  
> -	if (block > 0xffffffff) {
> +		memset(SCpnt->cmnd, 0, SD_EXT_CDB_SIZE);
> +		SCpnt->cmnd[0] = VARIABLE_LENGTH_CMD;
> +		SCpnt->cmnd[7] = 0x18;
> +		SCpnt->cmnd[9] = (rq_data_dir(rq) == READ) ? READ_32 : WRITE_32;
> +		SCpnt->cmnd[10] = protect | (blk_fua_rq(rq) ? 0x8 : 0);
> +
> +		/* LBA */
> +		SCpnt->cmnd[12] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
> +		SCpnt->cmnd[13] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
> +		SCpnt->cmnd[14] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
> +		SCpnt->cmnd[15] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
> +		SCpnt->cmnd[16] = (unsigned char) (block >> 24) & 0xff;
> +		SCpnt->cmnd[17] = (unsigned char) (block >> 16) & 0xff;
> +		SCpnt->cmnd[18] = (unsigned char) (block >> 8) & 0xff;
> +		SCpnt->cmnd[19] = (unsigned char) block & 0xff;
> +
> +		/* Expected Indirect LBA */
> +		SCpnt->cmnd[20] = (unsigned char) (block >> 24) & 0xff;
> +		SCpnt->cmnd[21] = (unsigned char) (block >> 16) & 0xff;
> +		SCpnt->cmnd[22] = (unsigned char) (block >> 8) & 0xff;
> +		SCpnt->cmnd[23] = (unsigned char) block & 0xff;
> +
> +		/* Transfer length */
> +		SCpnt->cmnd[28] = (unsigned char) (this_count >> 24) & 0xff;
> +		SCpnt->cmnd[29] = (unsigned char) (this_count >> 16) & 0xff;
> +		SCpnt->cmnd[30] = (unsigned char) (this_count >> 8) & 0xff;
> +		SCpnt->cmnd[31] = (unsigned char) this_count & 0xff;
> +	} else if (block > 0xffffffff) {
>  		SCpnt->cmnd[0] += READ_16 - READ_6;
> -		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
> +		SCpnt->cmnd[1] = protect | (blk_fua_rq(rq) ? 0x8 : 0);
>  		SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
>  		SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
>  		SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
> @@ -572,7 +611,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
>  			this_count = 0xffff;
>  
>  		SCpnt->cmnd[0] += READ_10 - READ_6;
> -		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
> +		SCpnt->cmnd[1] = protect | (blk_fua_rq(rq) ? 0x8 : 0);
>  		SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
>  		SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
>  		SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
> @@ -1047,6 +1086,7 @@ static int sd_done(struct scsi_cmnd *SCpnt)
>  	int result = SCpnt->result;
>  	unsigned int good_bytes = result ? 0 : scsi_bufflen(SCpnt);
>  	struct scsi_sense_hdr sshdr;
> +	struct scsi_disk *sdkp = scsi_disk(SCpnt->request->rq_disk);
>  	int sense_valid = 0;
>  	int sense_deferred = 0;
>  
> @@ -1108,6 +1148,10 @@ static int sd_done(struct scsi_cmnd *SCpnt)
>  	if (rq_data_dir(SCpnt->request) == READ && scsi_prot_sg_count(SCpnt))
>  		sd_dif_complete(SCpnt, good_bytes);
>  
> +	if (scsi_host_dif_capable(sdkp->device->host, sdkp->protection_type)
> +	    == SD_DIF_TYPE2_PROTECTION)
> +		mempool_free(SCpnt->cmnd, sd_cdb_pool);
> +
>  	return good_bytes;
>  }
>  
> @@ -1271,12 +1315,7 @@ void sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffer)
>  
>  	sdkp->protection_type = type;
>  
> -	switch (type) {
> -	case SD_DIF_TYPE1_PROTECTION:
> -	case SD_DIF_TYPE3_PROTECTION:
> -		break;
> -
> -	default:
> +	if (type > SD_DIF_TYPE3_PROTECTION) {
>  		sd_printk(KERN_ERR, sdkp, "formatted with unsupported "	\
>  			  "protection type %u. Disabling disk!\n", type);
>  		sdkp->capacity = 0;
> @@ -2321,8 +2360,24 @@ static int __init init_sd(void)
>  	if (err)
>  		goto err_out_class;
>  
> +	sd_cdb_cache = kmem_cache_create("sd_ext_cdb", SD_EXT_CDB_SIZE,
> +					 0, 0, NULL);
> +	if (!sd_cdb_cache) {
> +		printk(KERN_ERR "sd: can't init extended cdb cache\n");
> +		goto err_out_class;
> +	}
> +
> +	sd_cdb_pool = mempool_create_slab_pool(SD_MEMPOOL_SIZE, sd_cdb_cache);
> +	if (!sd_cdb_pool) {
> +		printk(KERN_ERR "sd: can't init extended cdb pool\n");
> +		goto err_out_cache;
> +	}
> +
>  	return 0;
>  
> +err_out_cache:
> +	kmem_cache_destroy(sd_cdb_cache);
> +
>  err_out_class:
>  	class_unregister(&sd_disk_class);
>  err_out:
> @@ -2342,6 +2397,9 @@ static void __exit exit_sd(void)
>  
>  	SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));
>  
> +	mempool_destroy(sd_cdb_pool);
> +	kmem_cache_destroy(sd_cdb_cache);
> +
>  	scsi_unregister_driver(&sd_template.gendrv);
>  	class_unregister(&sd_disk_class);
>  
> diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
> index ce1f5f8..e374804 100644
> --- a/drivers/scsi/sd.h
> +++ b/drivers/scsi/sd.h
> @@ -37,6 +37,11 @@
>   */
>  #define SD_LAST_BUGGY_SECTORS	8
>  
> +enum {
> +	SD_EXT_CDB_SIZE = 32,	/* Extended CDB size */
> +	SD_MEMPOOL_SIZE = 2,	/* CDB pool size */
> +};
> +
>  struct scsi_disk {
>  	struct scsi_driver *driver;	/* always &sd_template */
>  	struct scsi_device *device;
> diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
> index 084478e..34c46ab 100644
> --- a/include/scsi/scsi.h
> +++ b/include/scsi/scsi.h
> @@ -129,6 +129,9 @@ struct scsi_cmnd;
>  #define MI_REPORT_TARGET_PGS  0x0a
>  /* values for maintenance out */
>  #define MO_SET_TARGET_PGS     0x0a
> +/* values for variable length command */
> +#define READ_32		      0x09
> +#define WRITE_32	      0x0b
>  
>  /* Values for T10/04-262r7 */
>  #define	ATA_16		      0x85	/* 16-byte pass-thru */