linux/include/scsi/scsi_cmnd.h
FUJITA Tomonori 824d7b570b [SCSI] scsi_lib: add scatter/gather data buffer accessors
This adds a set of accessors for the scsi data buffer. This is in
preparation for chaining sg lists and bidirectional requests (and
possibly, the mid-layer dma mapping).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2007-05-26 16:29:59 -05:00

158 lines
5.2 KiB
C

#ifndef _SCSI_SCSI_CMND_H
#define _SCSI_SCSI_CMND_H
#include <linux/dma-mapping.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/timer.h>
struct request;
struct scatterlist;
struct Scsi_Host;
struct scsi_device;
/* embedded in scsi_cmnd */
struct scsi_pointer {
char *ptr; /* data pointer */
int this_residual; /* left in this buffer */
struct scatterlist *buffer; /* which buffer */
int buffers_residual; /* how many buffers left */
dma_addr_t dma_handle;
volatile int Status;
volatile int Message;
volatile int have_data_in;
volatile int sent_command;
volatile int phase;
};
struct scsi_cmnd {
struct scsi_device *device;
struct list_head list; /* scsi_cmnd participates in queue lists */
struct list_head eh_entry; /* entry for the host eh_cmd_q */
int eh_eflags; /* Used by error handlr */
void (*done) (struct scsi_cmnd *); /* Mid-level done function */
/*
* A SCSI Command is assigned a nonzero serial_number before passed
* to the driver's queue command function. The serial_number is
* cleared when scsi_done is entered indicating that the command
* has been completed. It currently doesn't have much use other
* than printk's. Some lldd's use this number for other purposes.
* It's almost certain that such usages are either incorrect or
* meaningless. Please kill all usages other than printk's. Also,
* as this number is always identical to ->pid, please convert
* printk's to use ->pid, so that we can kill this field.
*/
unsigned long serial_number;
/*
* This is set to jiffies as it was when the command was first
* allocated. It is used to time how long the command has
* been outstanding
*/
unsigned long jiffies_at_alloc;
int retries;
int allowed;
int timeout_per_command;
unsigned char cmd_len;
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 request_bufflen; /* Actual request size */
struct timer_list eh_timeout; /* Used to time out the command. */
void *request_buffer; /* Actual requested buffer */
/* These elements define the operation we ultimately want to perform */
unsigned short use_sg; /* Number of pieces of scatter-gather */
unsigned short sglist_len; /* size of malloc'd scatter-gather list */
unsigned underflow; /* Return error if less than
this amount is transferred */
unsigned transfersize; /* How much we are guaranteed to
transfer with each SCSI transfer
(ie, between disconnect /
reconnects. Probably == sector
size */
int resid; /* Number of bytes requested to be
transferred less actual number
transferred (0 if not supported) */
struct request *request; /* The command we are
working on */
#define SCSI_SENSE_BUFFERSIZE 96
unsigned char sense_buffer[SCSI_SENSE_BUFFERSIZE];
/* obtained by REQUEST SENSE when
* CHECK CONDITION is received on original
* command (auto-sense) */
/* Low-level done function - can be used by low-level driver to point
* to completion function. Not used by mid/upper level code. */
void (*scsi_done) (struct scsi_cmnd *);
/*
* The following fields can be written to by the host specific code.
* Everything else should be left alone.
*/
struct scsi_pointer SCp; /* Scratchpad used by some host adapters */
unsigned char *host_scribble; /* The host adapter is allowed to
* call scsi_malloc and get some memory
* and hang it here. The host adapter
* is also expected to call scsi_free
* to release this memory. (The memory
* obtained by scsi_malloc is guaranteed
* to be at an address < 16Mb). */
int result; /* Status code from lower level driver */
unsigned char tag; /* SCSI-II queued command tag */
unsigned long pid; /* Process ID, starts at 0. Unique per host. */
};
extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
extern void scsi_put_command(struct scsi_cmnd *);
extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
struct device *);
extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
extern void scsi_finish_command(struct scsi_cmnd *cmd);
extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
size_t *offset, size_t *len);
extern void scsi_kunmap_atomic_sg(void *virt);
extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
extern void scsi_free_sgtable(struct scatterlist *, int);
extern int scsi_dma_map(struct scsi_cmnd *cmd);
extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
#define scsi_sg_count(cmd) ((cmd)->use_sg)
#define scsi_sglist(cmd) ((struct scatterlist *)(cmd)->request_buffer)
#define scsi_bufflen(cmd) ((cmd)->request_bufflen)
static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
{
cmd->resid = resid;
}
static inline int scsi_get_resid(struct scsi_cmnd *cmd)
{
return cmd->resid;
}
#define scsi_for_each_sg(cmd, sg, nseg, __i) \
for (__i = 0, sg = scsi_sglist(cmd); __i < (nseg); __i++, (sg)++)
#endif /* _SCSI_SCSI_CMND_H */