Re: [PATCH v2 05/40] scsi: prepare for using 16-bits defined sense codes

[Hannes Reinecke <hare@suse.de>]

On 9/3/26 5:41 AM, Damien Le Moal wrote:
> In preparation for handling sense codes and their qualifiers as a single
> 16-bits sense code field, with the values  defined as macros in
> include/scsi/scsi_sense.h, modify the definition of the structures
> scsi_failure and scsi_sense_hdr to introduce a 16-bits sense_code field
> as a union with the existing 8-bits asc and ascq fields.
> 
> This temporary modification allows accessing either the asc and ascq
> fields individually, or their combination as the 16-bits sense_code field.
> 
> The helper functions scsi_sense_asc(), scsi_sense_ascq() are defined to
> allow accessing the 8-bits ASC and ASCQ values from the sense_code filed
> of struct scsi_sense_hdr. The helper functions scsi_failure_asc() and
> scsi_failure_ascq() provide the same for the sense code field of struct
> scsi_failure.
> 
> The helper functions scsi_set_sense_buffer() and scsi_set_sense() are also
> added to wrap calls to scsi_build_sense_buffer() and scsi_build_sense()
> using a 16-bits sense code aregument instead of the 8-bits ASC and ASCQ
> arguments.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>   include/scsi/scsi_cmnd.h   |  7 +++++++
>   include/scsi/scsi_common.h | 31 +++++++++++++++++++++++++++++--
>   include/scsi/scsi_device.h | 25 +++++++++++++++++++++++--
>   3 files changed, 59 insertions(+), 4 deletions(-)
> 
> diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
> index 8ecfb94049db..bf6d69f0249f 100644
> --- a/include/scsi/scsi_cmnd.h
> +++ b/include/scsi/scsi_cmnd.h
> @@ -394,6 +394,13 @@ static inline unsigned scsi_transfer_length(struct scsi_cmnd *scmd)
>   extern void scsi_build_sense(struct scsi_cmnd *scmd, int desc,
>   			     u8 key, u8 asc, u8 ascq);
>   
> +static inline void scsi_set_sense(struct scsi_cmnd *scmd, int desc,
> +				  u8 key, u16 code)
> +{
> +	scsi_build_sense(scmd, desc, key, scsi_sense_code_asc(code),
> +			 scsi_sense_code_ascq(code));
> +}
> +
>   struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
>   				   blk_mq_req_flags_t flags);
>   
> diff --git a/include/scsi/scsi_common.h b/include/scsi/scsi_common.h
> index 00c8a16d3cd2..6fb2c290ba33 100644
> --- a/include/scsi/scsi_common.h
> +++ b/include/scsi/scsi_common.h
> @@ -71,8 +71,18 @@ extern u64 scsilun_to_int(struct scsi_lun *);
>   struct scsi_sense_hdr {		/* See SPC-3 section 4.5 */
>   	u8 response_code;	/* permit: 0x0, 0x70, 0x71, 0x72, 0x73 */
>   	u8 sense_key;
> -	u8 asc;
> -	u8 ascq;
> +	union {
> +		struct {
> +#if defined(__BIG_ENDIAN)
> +			u8 asc;
> +			u8 ascq;
> +#elif defined(__LITTLE_ENDIAN)
> +			u8 ascq;
> +			u8 asc;
> +#endif
> +		};
> +		u16 sense_code;
> +	};
>   	u8 byte4;
>   	u8 byte5;
>   	u8 byte6;
> @@ -87,10 +97,27 @@ static inline bool scsi_sense_valid(const struct scsi_sense_hdr *sshdr)
>   	return (sshdr->response_code & 0x70) == 0x70;
>   }
>   
> +static inline u8 scsi_sense_asc(const struct scsi_sense_hdr *sshdr)
> +{
> +	return scsi_sense_code_asc(sshdr->sense_code);
> +}
> +
> +static inline u8 scsi_sense_ascq(const struct scsi_sense_hdr *sshdr)
> +{
> +	return scsi_sense_code_ascq(sshdr->sense_code);
> +}
> +
>   extern bool scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
>   				 struct scsi_sense_hdr *sshdr);
>   
>   extern void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq);
> +
> +static inline void scsi_set_sense_buffer(int desc, u8 *buf, u8 key, u16 code)
> +{
> +	scsi_build_sense_buffer(desc, buf, key, scsi_sense_code_asc(code),
> +				scsi_sense_code_ascq(code));
> +}
> +
>   int scsi_set_sense_information(u8 *buf, int buf_len, u64 info);
>   int scsi_set_sense_field_pointer(u8 *buf, int buf_len, u16 fp, u8 bp, bool cd);
>   extern const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index e321471e8ca2..11910142ac50 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -518,6 +518,7 @@ extern void scsi_sanitize_inquiry_string(unsigned char *s, int len);
>    * to match any sense key, ASC, and ASCQ value.
>    */
>   #define SCMD_FAILURE_SENSE_KEY_ANY	0xff
> +#define SCMD_FAILURE_SENSE_CODE_ANY	0xffff
>   #define SCMD_FAILURE_ASC_ANY		0xff
>   #define SCMD_FAILURE_ASCQ_ANY		0xff
>   /* Always retry a matching failure. */
> @@ -526,8 +527,18 @@ extern void scsi_sanitize_inquiry_string(unsigned char *s, int len);
>   struct scsi_failure {
>   	int result;
>   	u8 sense_key;
> -	u8 asc;
> -	u8 ascq;
> +	union {
> +		struct {
> +#if defined(__BIG_ENDIAN)
> +			u8 asc;
> +			u8 ascq;
> +#elif defined(__LITTLE_ENDIAN)
> +			u8 ascq;
> +			u8 asc;
> +#endif
> +		};
> +		u16 sense_code;
> +	};
>   	/*
>   	 * Number of times scsi_execute_cmd will retry the failure. It does
>   	 * not count for the total_allowed.

Why do we have two definitions for the sense code header? Can't we 
combine it with the definitions in scsi_common.h ?

> @@ -537,6 +548,16 @@ struct scsi_failure {
>   	s8 retries;
>   };
>   
> +static inline u8 scsi_failure_asc(const struct scsi_failure *failure)
> +{
> +	return scsi_sense_code_asc(failure->sense_code);
> +}
> +
> +static inline u8 scsi_failure_ascq(const struct scsi_failure *failure)
> +{
> +	return scsi_sense_code_ascq(failure->sense_code);
> +}
> +
>   struct scsi_failures {
>   	/*
>   	 * If a scsi_failure does not have a retry limit setup this limit will

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich