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Commit 13b53b44 authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by James Bottomley
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[SCSI] st: add st_scsi_execute helper function 



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: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: default avatarKai Makisara <Kai.Makisara@kolumbus.fi>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent d0e1ae31

drivers/scsi/st.c

+54 −0
Original line number Diff line number Diff line
@@ -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. */

drivers/scsi/st.h

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ struct st_request { 
	int result;

	struct scsi_tape *stp;

	struct completion *waiting;

	struct bio *bio;

};



/* The tape buffer descriptor. */