linux/include/scsi/scsi_eh.h
Boaz Harrosh 6f9a35e2da [SCSI] bidirectional command support
At the block level bidi request uses req->next_rq pointer for a second
bidi_read request.
At Scsi-midlayer a second scsi_data_buffer structure is used for the
bidi_read part. This bidi scsi_data_buffer is put on
request->next_rq->special. Struct scsi_cmnd is not changed.

- Define scsi_bidi_cmnd() to return true if it is a bidi request and a
  second sgtable was allocated.

- Define scsi_in()/scsi_out() to return the in or out scsi_data_buffer
  from this command This API is to isolate users from the mechanics of
  bidi.

- Define scsi_end_bidi_request() to do what scsi_end_request() does but
  for a bidi request. This is necessary because bidi commands are a bit
  tricky here. (See comments in body)

- scsi_release_buffers() will also release the bidi_read scsi_data_buffer

- scsi_io_completion() on bidi commands will now call
  scsi_end_bidi_request() and return.

- The previous work done in scsi_init_io() is now done in a new
  scsi_init_sgtable() (which is 99% identical to old scsi_init_io())
  The new scsi_init_io() will call the above twice if needed also for
  the bidi_read command. Only at this point is a command bidi.

- In scsi_error.c at scsi_eh_prep/restore_cmnd() make sure bidi-lld is not
  confused by a get-sense command that looks like bidi. This is done
  by puting NULL at request->next_rq, and restoring.

[jejb: update to sg_table and resolve conflicts
also update to blk-end-request and resolve conflicts]

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-01-30 13:03:41 -06:00

91 lines
2.5 KiB
C

#ifndef _SCSI_SCSI_EH_H
#define _SCSI_SCSI_EH_H
#include <linux/scatterlist.h>
#include <scsi/scsi_cmnd.h>
struct scsi_device;
struct Scsi_Host;
/*
* This is a slightly modified SCSI sense "descriptor" format header.
* The addition is to allow the 0x70 and 0x71 response codes. The idea
* is to place the salient data from either "fixed" or "descriptor" sense
* format into one structure to ease application processing.
*
* The original sense buffer should be kept around for those cases
* in which more information is required (e.g. the LBA of a MEDIUM ERROR).
*/
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;
u8 byte4;
u8 byte5;
u8 byte6;
u8 additional_length; /* always 0 for fixed sense format */
};
static inline int scsi_sense_valid(struct scsi_sense_hdr *sshdr)
{
if (!sshdr)
return 0;
return (sshdr->response_code & 0x70) == 0x70;
}
extern void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
struct list_head *done_q);
extern void scsi_eh_flush_done_q(struct list_head *done_q);
extern void scsi_report_bus_reset(struct Scsi_Host *, int);
extern void scsi_report_device_reset(struct Scsi_Host *, int, int);
extern int scsi_block_when_processing_errors(struct scsi_device *);
extern int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
struct scsi_sense_hdr *sshdr);
extern int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
struct scsi_sense_hdr *sshdr);
static inline int scsi_sense_is_deferred(struct scsi_sense_hdr *sshdr)
{
return ((sshdr->response_code >= 0x70) && (sshdr->response_code & 1));
}
extern const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
int desc_type);
extern int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
u64 * info_out);
/*
* Reset request from external source
*/
#define SCSI_TRY_RESET_DEVICE 1
#define SCSI_TRY_RESET_BUS 2
#define SCSI_TRY_RESET_HOST 3
extern int scsi_reset_provider(struct scsi_device *, int);
struct scsi_eh_save {
/* saved state */
int result;
enum dma_data_direction data_direction;
unsigned char cmd_len;
unsigned char cmnd[MAX_COMMAND_SIZE];
struct scsi_data_buffer sdb;
struct request *next_rq;
/* new command support */
struct scatterlist sense_sgl;
};
extern void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd,
struct scsi_eh_save *ses, unsigned char *cmnd,
int cmnd_size, unsigned sense_bytes);
extern void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd,
struct scsi_eh_save *ses);
#endif /* _SCSI_SCSI_EH_H */