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[SCSI] st: add st_scsi_execute helper function

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st_scsi_execute is a helper function to perform SCSI commands
involving data transfer between user and kernel space (st_read and
st_write).

It's the future plan to combine this with st_scsi_kern_execute helper
function.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Kai Makisara <Kai.Makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
FUJITA Tomonori 2008-12-18 14:49:41 +09:00 committed by James Bottomley
parent d0e1ae31be
commit 13b53b4434
2 changed files with 55 additions and 0 deletions
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54
drivers/scsi/st.c
View File

@ -475,6 +475,60 @@ static void st_release_request(struct st_request *streq)
kfree(streq);
}
static void st_scsi_execute_end(struct request *req, int uptodate)
{
struct st_request *SRpnt = req->end_io_data;
struct scsi_tape *STp = SRpnt->stp;
STp->buffer->cmdstat.midlevel_result = SRpnt->result = req->errors;
STp->buffer->cmdstat.residual = req->data_len;
if (SRpnt->waiting)
complete(SRpnt->waiting);
blk_rq_unmap_user(SRpnt->bio);
__blk_put_request(req->q, req);
}
static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
int data_direction, void *buffer, unsigned bufflen,
int timeout, int retries)
{
struct request *req;
struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
int err = 0;
int write = (data_direction == DMA_TO_DEVICE);
req = blk_get_request(SRpnt->stp->device->request_queue, write,
GFP_KERNEL);
if (!req)
return DRIVER_ERROR << 24;
req->cmd_type = REQ_TYPE_BLOCK_PC;
req->cmd_flags |= REQ_QUIET;
mdata->null_mapped = 1;
err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen, GFP_KERNEL);
if (err) {
blk_put_request(req);
return DRIVER_ERROR << 24;
}
SRpnt->bio = req->bio;
req->cmd_len = COMMAND_SIZE(cmd[0]);
memset(req->cmd, 0, BLK_MAX_CDB);
memcpy(req->cmd, cmd, req->cmd_len);
req->sense = SRpnt->sense;
req->sense_len = 0;
req->timeout = timeout;
req->retries = retries;
req->end_io_data = SRpnt;
blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
return 0;
}
/* Do the scsi command. Waits until command performed if do_wait is true.
Otherwise write_behind_check() is used to check that the command
has finished. */

1
drivers/scsi/st.h
View File

@ -29,6 +29,7 @@ struct st_request {
int result;
struct scsi_tape *stp;
struct completion *waiting;
struct bio *bio;
};
/* The tape buffer descriptor. */