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scsi: core: Remove the cmd field from struct scsi_request

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Now that each scsi_request is backed by a scsi_cmnd, there is no need to
indirect the CDB storage.  Change all submitters of SCSI passthrough
requests to store the CDB information directly in the scsi_cmnd, and while
doing so allocate the full 32 bytes that cover all Linux supported SCSI
hosts instead of requiring dynamic allocation for > 16 byte CDBs.  On
64-bit systems this does not change the size of the scsi_cmnd at all, while
on 32-bit systems it slightly increases it for now, but that increase will
be made up by the removal of the remaining scsi_request fields.

Link: https://lore.kernel.org/r/20220224175552.988286-4-hch@lst.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Christoph Hellwig
2022-02-24 18:55:47 +01:00
committed by Martin K. Petersen
parent 71bada345b
commit ce70fd9a55
19 changed files with 113 additions and 168 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
include/scsi/scsi_cmnd.h
View File

@@ -28,9 +28,6 @@ struct scsi_driver;
* 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;
@@ -100,9 +97,7 @@ struct scsi_cmnd {
unsigned short cmd_len;
enum dma_data_direction sc_data_direction;
/* These elements define the operation we are about to perform */
unsigned char *cmnd;
unsigned char cmnd[32]; /* SCSI CDB */
/* These elements define the operation we ultimately want to perform */
struct scsi_data_buffer sdb;

4
include/scsi/scsi_eh.h
View File

@@ -38,10 +38,8 @@ struct scsi_eh_save {
unsigned underflow;
unsigned char cmd_len;
unsigned char prot_op;
unsigned char *cmnd;
unsigned char cmnd[32];
struct scsi_data_buffer sdb;
/* new command support */
unsigned char eh_cmnd[BLK_MAX_CDB];
struct scatterlist sense_sgl;
};

11
include/scsi/scsi_request.h
View File

@@ -4,12 +4,7 @@
#include <linux/blk-mq.h>
#define BLK_MAX_CDB 16
struct scsi_request {
unsigned char __cmd[BLK_MAX_CDB];
unsigned char *cmd;
unsigned short cmd_len;
int result;
unsigned int sense_len;
unsigned int resid_len; /* residual count */
@@ -22,10 +17,4 @@ static inline struct scsi_request *scsi_req(struct request *rq)
return blk_mq_rq_to_pdu(rq);
}
static inline void scsi_req_free_cmd(struct scsi_request *req)
{
if (req->cmd != req->__cmd)
kfree(req->cmd);
}
#endif /* _SCSI_SCSI_REQUEST_H */