Commit 30b0c37b authored by Boaz Harrosh's avatar Boaz Harrosh Committed by James Bottomley
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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: default avatarBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent bb52d82f
......@@ -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);
......
......@@ -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)
......
......@@ -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;
......
......@@ -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;
}
......
......@@ -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;
......
......@@ -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;
......
......@@ -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;
}
......
......@@ -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) \
......
......@@ -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;
};
......
......@@ -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
*
......
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