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[SCSI] implement scsi_data_buffer 

In preparation for bidi we abstract all IO members of scsi_cmnd,
that will need to duplicate, into a substructure.

- Group all IO members of scsi_cmnd into a scsi_data_buffer
  structure.
- Adjust accessors to new members.
- scsi_{alloc,free}_sgtable receive a scsi_data_buffer instead of
  scsi_cmnd. And work on it.
- Adjust scsi_init_io() and  scsi_release_buffers() for above
  change.
- Fix other parts of scsi_lib/scsi.c to members migration. Use
  accessors where appropriate.

- fix Documentation about scsi_cmnd in scsi_host.h

- scsi_error.c
  * Changed needed members of struct scsi_eh_save.
  * Careful considerations in scsi_eh_prep/restore_cmnd.

- sd.c and sr.c
  * sd and sr would adjust IO size to align on device's block
    size so code needs to change once we move to scsi_data_buff
    implementation.
  * Convert code to use scsi_for_each_sg
  * Use data accessors where appropriate.

- tgt: convert libsrp to use scsi_data_buffer

- isd200: This driver still bangs on scsi_cmnd IO members,
  so need changing

[jejb: rebased on top of sg_table patches fixed up conflicts
and used the synergy to eliminate use_sg and sg_count]

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
Boaz Harrosh 2007-12-13 13:47:40 +02:00 committed by James Bottomley
parent bb52d82f45
commit 30b0c37b27
10 changed files with 85 additions and 99 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/scsi/libsrp.c
View File

@ -426,8 +426,8 @@ int srp_cmd_queue(struct Scsi_Host *shost, struct srp_cmd *cmd, void *info,
sc->SCp.ptr = info;
memcpy(sc->cmnd, cmd->cdb, MAX_COMMAND_SIZE);
sc->request_bufflen = len;
sc->request_buffer = (void *) (unsigned long) addr;
sc->sdb.length = len;
sc->sdb.table.sgl = (void *) (unsigned long) addr;
sc->tag = tag;
err = scsi_tgt_queue_command(sc, itn_id, (struct scsi_lun *)&cmd->lun,
cmd->tag);

2
drivers/scsi/scsi.c
View File

@ -757,7 +757,7 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
"Notifying upper driver of completion "
"(result %x)\n", cmd->result));
good_bytes = cmd->request_bufflen;
good_bytes = scsi_bufflen(cmd);
if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
drv = scsi_cmd_to_driver(cmd);
if (drv->done)

30
drivers/scsi/scsi_error.c
View File

@ -617,29 +617,25 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
ses->cmd_len = scmd->cmd_len;
memcpy(ses->cmnd, scmd->cmnd, sizeof(scmd->cmnd));
ses->data_direction = scmd->sc_data_direction;
ses->bufflen = scmd->request_bufflen;
ses->buffer = scmd->request_buffer;
ses->use_sg = scmd->use_sg;
ses->resid = scmd->resid;
ses->sdb = scmd->sdb;
ses->result = scmd->result;
memset(&scmd->sdb, 0, sizeof(scmd->sdb));
if (sense_bytes) {
scmd->request_bufflen = min_t(unsigned,
SCSI_SENSE_BUFFERSIZE, sense_bytes);
scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
sense_bytes);
sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
scmd->request_bufflen);
scmd->request_buffer = &ses->sense_sgl;
scmd->sdb.length);
scmd->sdb.table.sgl = &ses->sense_sgl;
scmd->sc_data_direction = DMA_FROM_DEVICE;
scmd->use_sg = 1;
scmd->sdb.table.nents = 1;
memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
scmd->cmnd[0] = REQUEST_SENSE;
scmd->cmnd[4] = scmd->request_bufflen;
scmd->cmnd[4] = scmd->sdb.length;
scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
} else {
scmd->request_buffer = NULL;
scmd->request_bufflen = 0;
scmd->sc_data_direction = DMA_NONE;
scmd->use_sg = 0;
if (cmnd) {
memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
memcpy(scmd->cmnd, cmnd, cmnd_size);
@ -676,10 +672,7 @@ void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
scmd->cmd_len = ses->cmd_len;
memcpy(scmd->cmnd, ses->cmnd, sizeof(scmd->cmnd));
scmd->sc_data_direction = ses->data_direction;
scmd->request_bufflen = ses->bufflen;
scmd->request_buffer = ses->buffer;
scmd->use_sg = ses->use_sg;
scmd->resid = ses->resid;
scmd->sdb = ses->sdb;
scmd->result = ses->result;
}
EXPORT_SYMBOL(scsi_eh_restore_cmnd);
@ -1700,8 +1693,7 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
scmd->scsi_done = scsi_reset_provider_done_command;
scmd->request_buffer = NULL;
scmd->request_bufflen = 0;
memset(&scmd->sdb, 0, sizeof(scmd->sdb));
scmd->cmd_len = 0;

63
drivers/scsi/scsi_lib.c
View File

@ -440,7 +440,7 @@ EXPORT_SYMBOL_GPL(scsi_execute_async);
static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
{
cmd->serial_number = 0;
cmd->resid = 0;
scsi_set_resid(cmd, 0);
memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
if (cmd->cmd_len == 0)
cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
@ -746,25 +746,25 @@ static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
return mempool_alloc(sgp->pool, gfp_mask);
}
static int scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
gfp_t gfp_mask)
{
int ret;
BUG_ON(!cmd->use_sg);
BUG_ON(!nents);
ret = __sg_alloc_table(&cmd->sg_table, cmd->use_sg,
SCSI_MAX_SG_SEGMENTS, gfp_mask, scsi_sg_alloc);
ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
gfp_mask, scsi_sg_alloc);
if (unlikely(ret))
__sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS,
__sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
scsi_sg_free);
cmd->request_buffer = cmd->sg_table.sgl;
return ret;
}
static void scsi_free_sgtable(struct scsi_cmnd *cmd)
static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
{
__sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
__sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
}
/*
@ -786,15 +786,10 @@ static void scsi_free_sgtable(struct scsi_cmnd *cmd)
*/
void scsi_release_buffers(struct scsi_cmnd *cmd)
{
if (cmd->use_sg)
scsi_free_sgtable(cmd);
if (cmd->sdb.table.nents)
scsi_free_sgtable(&cmd->sdb);
/*
* Zero these out. They now point to freed memory, and it is
* dangerous to hang onto the pointers.
*/
cmd->request_buffer = NULL;
cmd->request_bufflen = 0;
memset(&cmd->sdb, 0, sizeof(cmd->sdb));
}
EXPORT_SYMBOL(scsi_release_buffers);
@ -829,7 +824,7 @@ EXPORT_SYMBOL(scsi_release_buffers);
void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
{
int result = cmd->result;
int this_count = cmd->request_bufflen;
int this_count = scsi_bufflen(cmd);
struct request_queue *q = cmd->device->request_queue;
struct request *req = cmd->request;
int clear_errors = 1;
@ -837,8 +832,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
int sense_valid = 0;
int sense_deferred = 0;
scsi_release_buffers(cmd);
if (result) {
sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
if (sense_valid)
@ -861,9 +854,11 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
req->sense_len = len;
}
}
req->data_len = cmd->resid;
req->data_len = scsi_get_resid(cmd);
}
scsi_release_buffers(cmd);
/*
* Next deal with any sectors which we were able to correctly
* handle.
@ -871,7 +866,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
"%d bytes done.\n",
req->nr_sectors, good_bytes));
SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
if (clear_errors)
req->errors = 0;
@ -1002,35 +996,30 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
{
struct request *req = cmd->request;
int count;
/*
* We used to not use scatter-gather for single segment request,
* but now we do (it makes highmem I/O easier to support without
* kmapping pages)
*/
cmd->use_sg = req->nr_phys_segments;
struct scsi_data_buffer *sdb = &cmd->sdb;
/*
* If sg table allocation fails, requeue request later.
*/
if (unlikely(scsi_alloc_sgtable(cmd, gfp_mask))) {
if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
gfp_mask))) {
scsi_unprep_request(req);
return BLKPREP_DEFER;
}
req->buffer = NULL;
if (blk_pc_request(req))
cmd->request_bufflen = req->data_len;
sdb->length = req->data_len;
else
cmd->request_bufflen = req->nr_sectors << 9;
sdb->length = req->nr_sectors << 9;
/*
* Next, walk the list, and fill in the addresses and sizes of
* each segment.
*/
count = blk_rq_map_sg(req->q, req, cmd->request_buffer);
BUG_ON(count > cmd->use_sg);
cmd->use_sg = count;
count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
BUG_ON(count > sdb->table.nents);
sdb->table.nents = count;
return BLKPREP_OK;
}
EXPORT_SYMBOL(scsi_init_io);
@ -1086,9 +1075,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
BUG_ON(req->data_len);
BUG_ON(req->data);
cmd->request_bufflen = 0;
cmd->request_buffer = NULL;
cmd->use_sg = 0;
memset(&cmd->sdb, 0, sizeof(cmd->sdb));
req->buffer = NULL;
}

4
drivers/scsi/sd.c
View File

@ -519,7 +519,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
SCpnt->cmnd[4] = (unsigned char) this_count;
SCpnt->cmnd[5] = 0;
}
SCpnt->request_bufflen = this_count * sdp->sector_size;
SCpnt->sdb.length = this_count * sdp->sector_size;
/*
* We shouldn't disconnect in the middle of a sector, so with a dumb
@ -926,7 +926,7 @@ static struct block_device_operations sd_fops = {
static int sd_done(struct scsi_cmnd *SCpnt)
{
int result = SCpnt->result;
unsigned int xfer_size = SCpnt->request_bufflen;
unsigned int xfer_size = scsi_bufflen(SCpnt);
unsigned int good_bytes = result ? 0 : xfer_size;
u64 start_lba = SCpnt->request->sector;
u64 bad_lba;

25
drivers/scsi/sr.c
View File

@ -231,7 +231,7 @@ out:
static int sr_done(struct scsi_cmnd *SCpnt)
{
int result = SCpnt->result;
int this_count = SCpnt->request_bufflen;
int this_count = scsi_bufflen(SCpnt);
int good_bytes = (result == 0 ? this_count : 0);
int block_sectors = 0;
long error_sector;
@ -379,17 +379,18 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
}
{
struct scatterlist *sg = SCpnt->request_buffer;
int i, size = 0;
for (i = 0; i < SCpnt->use_sg; i++)
size += sg[i].length;
struct scatterlist *sg;
int i, size = 0, sg_count = scsi_sg_count(SCpnt);
if (size != SCpnt->request_bufflen && SCpnt->use_sg) {
scsi_for_each_sg(SCpnt, sg, sg_count, i)
size += sg->length;
if (size != scsi_bufflen(SCpnt)) {
scmd_printk(KERN_ERR, SCpnt,
"mismatch count %d, bytes %d\n",
size, SCpnt->request_bufflen);
if (SCpnt->request_bufflen > size)
SCpnt->request_bufflen = size;
size, scsi_bufflen(SCpnt));
if (scsi_bufflen(SCpnt) > size)
SCpnt->sdb.length = size;
}
}
@ -397,12 +398,12 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
* request doesn't start on hw block boundary, add scatter pads
*/
if (((unsigned int)rq->sector % (s_size >> 9)) ||
(SCpnt->request_bufflen % s_size)) {
(scsi_bufflen(SCpnt) % s_size)) {
scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
goto out;
}
this_count = (SCpnt->request_bufflen >> 9) / (s_size >> 9);
this_count = (scsi_bufflen(SCpnt) >> 9) / (s_size >> 9);
SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
@ -416,7 +417,7 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
if (this_count > 0xffff) {
this_count = 0xffff;
SCpnt->request_bufflen = this_count * s_size;
SCpnt->sdb.length = this_count * s_size;
}
SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;

8
drivers/usb/storage/isd200.c
View File

@ -415,14 +415,14 @@ static void isd200_set_srb(struct isd200_info *info,
sg_init_one(&info->sg, buff, bufflen);
srb->sc_data_direction = dir;
srb->request_buffer = buff ? &info->sg : NULL;
srb->request_bufflen = bufflen;
srb->use_sg = buff ? 1 : 0;
srb->sdb.table.sgl = buff ? &info->sg : NULL;
srb->sdb.length = bufflen;
srb->sdb.table.nents = buff ? 1 : 0;
}
static void isd200_srb_set_bufflen(struct scsi_cmnd *srb, unsigned bufflen)
{
srb->request_bufflen = bufflen;
srb->sdb.length = bufflen;
}

36
include/scsi/scsi_cmnd.h
View File

@ -11,6 +11,11 @@ struct request;
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 {
@ -61,15 +66,11 @@ struct scsi_cmnd {
/* 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 */
struct sg_table sg_table;
unsigned short use_sg; /* Number of pieces of scatter-gather */
struct scsi_data_buffer sdb;
unsigned underflow; /* Return error if less than
this amount is transferred */
@ -79,10 +80,6 @@ struct scsi_cmnd {
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 */
@ -133,18 +130,29 @@ 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);
#define scsi_sg_count(cmd) ((cmd)->use_sg)
#define scsi_sglist(cmd) ((cmd)->sg_table.sgl)
#define scsi_bufflen(cmd) ((cmd)->request_bufflen)
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->resid = resid;
cmd->sdb.resid = resid;
}
static inline int scsi_get_resid(struct scsi_cmnd *cmd)
{
return cmd->resid;
return cmd->sdb.resid;
}
#define scsi_for_each_sg(cmd, sg, nseg, __i) \

8
include/scsi/scsi_eh.h
View File

@ -68,16 +68,14 @@ extern int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
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;
void *buffer;
unsigned bufflen;
unsigned short use_sg;
int resid;
/* new command support */
struct scatterlist sense_sgl;
};

4
include/scsi/scsi_host.h
View File

@ -136,9 +136,9 @@ struct scsi_host_template {
* the done callback is invoked.
*
* This is called to inform the LLD to transfer
* cmd->request_bufflen bytes. The cmd->use_sg speciefies the
* scsi_bufflen(cmd) bytes. scsi_sg_count(cmd) speciefies the
* number of scatterlist entried in the command and
* cmd->request_buffer contains the scatterlist.
* scsi_sglist(cmd) returns the scatterlist.
*
* return values: see queuecommand
*