linux/include/scsi/scsi_cmnd.h

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#ifndef _SCSI_SCSI_CMND_H
#define _SCSI_SCSI_CMND_H
#include <linux/dma-mapping.h>
[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>
2007-12-13 12:50:53 +01:00
#include <linux/blkdev.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/scatterlist.h>
struct Scsi_Host;
struct scsi_device;
struct scsi_data_buffer {
struct sg_table table;
unsigned length;
int resid;
};
/* 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 */
/*
* 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 is a bug for LLDDs to use this number
* for purposes other than printk (and even that is only useful
* for debugging).
*/
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];
struct timer_list eh_timeout; /* Used to time out the command. */
/* These elements define the operation we ultimately want to perform */
struct scsi_data_buffer sdb;
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 */
struct request *request; /* The command we are
working on */
#define SCSI_SENSE_BUFFERSIZE 96
unsigned char *sense_buffer;
/* 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 */
};
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_finish_command(struct scsi_cmnd *cmd);
extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
[SCSI] dc395x: dynamically map scatter-gather for PIO The current dc395x driver uses PIO to transfer up to 4 bytes which do not get transferred by DMA (under unclear circumstances). For this the driver uses page_address() which is broken on highmem. Apart from this the actual calculation of the virtual address is wrong (even without highmem). So, e.g., for reading it reads bytes from the driver to a wrong address and returns wrong data, I guess, for writing it would just output random data to the device. The proper fix, as suggested by many, is to dynamically map data using kmap_atomic(page, KM_BIO_SRC_IRQ) / kunmap_atomic(virt). The reason why it has not been done until now, although I've done some preliminary patches more than a year ago was that nobody interested in fixing this problem was able to reliably reproduce it. Now it changed - with the help from Sebastian Frei (CC'ed) I was able to trigger the PIO path. Thus, I was also able to test and debug it. There are 4 cases when PIO is used in dc395x - data-in / -out with and without scatter-gather. I was able to reproduce and test only data-in with and without SG. So, the data-out path is still untested, but it is also somewhat simpler than the data-in. Fredrik Roubert (also CC'ed) also had PIO triggering on his system, and in his case it was data-out without SG. It would be great if he could test the attached patch on his system, but even if he cannot, I would still request to apply the patch and just wait if anybody cries... Implementation: I put 2 new functions in scsi_lib.c and their declarations in scsi_cmnd.h. I exported them without _GPL, although, I don't feel strongly about that - not many drivers are likely to use them. But there is at least one more - I want to use them in tmscsim.c. Whether these are the right files for the functions and their declarations - not sure either. Actually, they are not scsi-specific, so, might go somewhere around other scattergather magic? They are not platform specific either, and most SG functions are defined under arch/*/... As these issues were discussed previously there were some more routines suggested to manipulate scattergather buffers, I think, some of them were needed around crypto code... So, might be a common place reasonable, like lib/scattergather.c? I am open here. Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2006-04-02 21:57:43 +02:00
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 int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask);
extern void scsi_release_buffers(struct scsi_cmnd *cmd);
extern int scsi_dma_map(struct scsi_cmnd *cmd);
extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
{
return cmd->sdb.table.nents;
}
static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
{
return cmd->sdb.table.sgl;
}
static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
{
return cmd->sdb.length;
}
static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
{
cmd->sdb.resid = resid;
}
static inline int scsi_get_resid(struct scsi_cmnd *cmd)
{
return cmd->sdb.resid;
}
#define scsi_for_each_sg(cmd, sg, nseg, __i) \
for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
[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>
2007-12-13 12:50:53 +01:00
static inline int scsi_bidi_cmnd(struct scsi_cmnd *cmd)
{
return blk_bidi_rq(cmd->request) &&
(cmd->request->next_rq->special != NULL);
}
static inline struct scsi_data_buffer *scsi_in(struct scsi_cmnd *cmd)
{
return scsi_bidi_cmnd(cmd) ?
cmd->request->next_rq->special : &cmd->sdb;
}
static inline struct scsi_data_buffer *scsi_out(struct scsi_cmnd *cmd)
{
return &cmd->sdb;
}
#endif /* _SCSI_SCSI_CMND_H */