From 64a87b244b9297667ca80264aab849a36f494884 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Wed, 30 Apr 2008 11:19:47 +0300 Subject: [SCSI] Let scsi_cmnd->cmnd use request->cmd buffer - struct scsi_cmnd had a 16 bytes command buffer of its own. This is an unnecessary duplication and copy of request's cmd. It is probably left overs from the time that scsi_cmnd could function without a request attached. So clean that up. - Once above is done, few places, apart from scsi-ml, needed adjustments due to changing the data type of scsi_cmnd->cmnd. - Lots of drivers still use MAX_COMMAND_SIZE. So I have left that #define but equate it to BLK_MAX_CDB. The way I see it and is reflected in the patch below is. MAX_COMMAND_SIZE - means: The longest fixed-length (*) SCSI CDB as per the SCSI standard and is not related to the implementation. BLK_MAX_CDB. - The allocated space at the request level - I have audit all ISA drivers and made sure none use ->cmnd in a DMA Operation. Same audit was done by Andi Kleen. (*)fixed-length here means commands that their size can be determined by their opcode and the CDB does not carry a length specifier, (unlike the VARIABLE_LENGTH_CMD(0x7f) command). This is actually not exactly true and the SCSI standard also defines extended commands and vendor specific commands that can be bigger than 16 bytes. The kernel will support these using the same infrastructure used for VARLEN CDB's. So in effect MAX_COMMAND_SIZE means the maximum size command scsi-ml supports without specifying a cmd_len by ULD's Signed-off-by: Boaz Harrosh Signed-off-by: James Bottomley --- include/scsi/scsi_cmnd.h | 21 +++++++++++++++++++-- include/scsi/scsi_eh.h | 4 ++-- 2 files changed, 21 insertions(+), 4 deletions(-) (limited to 'include/scsi') diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index 8d20e60a94b..7ed883c8e48 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -7,10 +7,28 @@ #include #include #include +#include struct Scsi_Host; struct scsi_device; +/* + * MAX_COMMAND_SIZE is: + * The longest fixed-length SCSI CDB as per the SCSI standard. + * fixed-length means: commands that their size can be determined + * by their opcode and the CDB does not carry a length specifier, (unlike + * the VARIABLE_LENGTH_CMD(0x7f) command). This is actually not exactly + * true and the SCSI standard also defines extended commands and + * vendor specific commands that can be bigger than 16 bytes. The kernel + * will support these using the same infrastructure used for VARLEN CDB's. + * So in effect MAX_COMMAND_SIZE means the maximum size command scsi-ml + * supports without specifying a cmd_len by ULD's + */ +#define MAX_COMMAND_SIZE 16 +#if (MAX_COMMAND_SIZE > BLK_MAX_CDB) +# error MAX_COMMAND_SIZE can not be bigger than BLK_MAX_CDB +#endif + struct scsi_data_buffer { struct sg_table table; unsigned length; @@ -64,8 +82,7 @@ struct scsi_cmnd { enum dma_data_direction sc_data_direction; /* These elements define the operation we are about to perform */ -#define MAX_COMMAND_SIZE 16 - unsigned char cmnd[MAX_COMMAND_SIZE]; + unsigned char *cmnd; struct timer_list eh_timeout; /* Used to time out the command. */ diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h index d3a133b4a07..2a9add21267 100644 --- a/include/scsi/scsi_eh.h +++ b/include/scsi/scsi_eh.h @@ -75,11 +75,11 @@ struct scsi_eh_save { int result; enum dma_data_direction data_direction; unsigned char cmd_len; - unsigned char cmnd[MAX_COMMAND_SIZE]; + unsigned char *cmnd; struct scsi_data_buffer sdb; struct request *next_rq; - /* new command support */ + unsigned char eh_cmnd[BLK_MAX_CDB]; struct scatterlist sense_sgl; }; -- cgit v1.2.3 From db4742dd8f0aa9125b74f9b2516336a75f3d9106 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Wed, 30 Apr 2008 11:27:26 +0300 Subject: [SCSI] add support for variable length extended commands Add support for variable-length, extended, and vendor specific CDBs to scsi-ml. It is now possible for initiators and ULD's to issue these types of commands. LLDs need not change much. All they need is to raise the .max_cmd_len to the longest command they support (see iscsi patch). - clean-up some code paths that did not expect commands to be larger than 16, and change cmd_len members' type to short as char is not enough. Signed-off-by: Boaz Harrosh Signed-off-by: Benny Halevy Signed-off-by: James Bottomley --- include/scsi/scsi.h | 40 +++++++++++++++++++++++++++++++++------- include/scsi/scsi_cmnd.h | 2 +- include/scsi/scsi_host.h | 8 +++----- 3 files changed, 37 insertions(+), 13 deletions(-) (limited to 'include/scsi') diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h index 1f74bcd603f..32742c4563d 100644 --- a/include/scsi/scsi.h +++ b/include/scsi/scsi.h @@ -29,13 +29,6 @@ #define SCSI_MAX_SG_CHAIN_SEGMENTS SCSI_MAX_SG_SEGMENTS #endif -/* - * SCSI command lengths - */ - -extern const unsigned char scsi_command_size[8]; -#define COMMAND_SIZE(opcode) scsi_command_size[((opcode) >> 5) & 7] - /* * Special value for scanning to specify scanning or rescanning of all * possible channels, (target) ids, or luns on a given shost. @@ -109,6 +102,7 @@ extern const unsigned char scsi_command_size[8]; #define MODE_SENSE_10 0x5a #define PERSISTENT_RESERVE_IN 0x5e #define PERSISTENT_RESERVE_OUT 0x5f +#define VARIABLE_LENGTH_CMD 0x7f #define REPORT_LUNS 0xa0 #define MAINTENANCE_IN 0xa3 #define MOVE_MEDIUM 0xa5 @@ -135,6 +129,38 @@ extern const unsigned char scsi_command_size[8]; #define ATA_16 0x85 /* 16-byte pass-thru */ #define ATA_12 0xa1 /* 12-byte pass-thru */ +/* + * SCSI command lengths + */ + +#define SCSI_MAX_VARLEN_CDB_SIZE 260 + +/* defined in T10 SCSI Primary Commands-2 (SPC2) */ +struct scsi_varlen_cdb_hdr { + u8 opcode; /* opcode always == VARIABLE_LENGTH_CMD */ + u8 control; + u8 misc[5]; + u8 additional_cdb_length; /* total cdb length - 8 */ + __be16 service_action; + /* service specific data follows */ +}; + +static inline unsigned +scsi_varlen_cdb_length(const void *hdr) +{ + return ((struct scsi_varlen_cdb_hdr *)hdr)->additional_cdb_length + 8; +} + +extern const unsigned char scsi_command_size_tbl[8]; +#define COMMAND_SIZE(opcode) scsi_command_size_tbl[((opcode) >> 5) & 7] + +static inline unsigned +scsi_command_size(const unsigned char *cmnd) +{ + return (cmnd[0] == VARIABLE_LENGTH_CMD) ? + scsi_varlen_cdb_length(cmnd) : COMMAND_SIZE(cmnd[0]); +} + /* * SCSI Architecture Model (SAM) Status codes. Taken from SAM-3 draft * T10/1561-D Revision 4 Draft dated 7th November 2002. diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index 7ed883c8e48..3e46dfae819 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -78,7 +78,7 @@ struct scsi_cmnd { int allowed; int timeout_per_command; - unsigned char cmd_len; + unsigned short cmd_len; enum dma_data_direction sc_data_direction; /* These elements define the operation we are about to perform */ diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index d967d6dc7a2..1834fdfe82a 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -573,13 +573,11 @@ struct Scsi_Host { /* * The maximum length of SCSI commands that this host can accept. * Probably 12 for most host adapters, but could be 16 for others. + * or 260 if the driver supports variable length cdbs. * For drivers that don't set this field, a value of 12 is - * assumed. I am leaving this as a number rather than a bit - * because you never know what subsequent SCSI standards might do - * (i.e. could there be a 20 byte or a 24-byte command a few years - * down the road?). + * assumed. */ - unsigned char max_cmd_len; + unsigned short max_cmd_len; int this_id; int can_queue; -- cgit v1.2.3