st_scsi_kern_execute is a helper function to perform SCSI commands
synchronously. It supports data transfer with a liner in-kernel buffer
(not scatter gather). st_scsi_kern_execute internally uses
blk_get_request, blk_rq_map_kern, and blk_execute_rq.
The majority of st_do_scsi can be replaced with
st_scsi_kern_execute. This is a preparation for rewriting st_do_scsi
to remove obsolete scsi_execute_async().
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
---
drivers/scsi/st.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 49 insertions(+), 0 deletions(-)
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 878493d..6179940 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -533,6 +533,55 @@ st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd
return SRpnt;
}
+static int st_scsi_kern_execute(struct st_request *streq,
+ const unsigned char *cmd, int data_direction,
+ void *buffer, unsigned bufflen, int timeout,
+ int retries)
+{
+ struct scsi_tape *stp = streq->stp;
+ struct request *req;
+ int write = (data_direction == DMA_TO_DEVICE);
+ int ret = 0;
+
+ /* st_do_scsi returns -EBUSY in case of OOM */
+ req = blk_get_request(stp->device->request_queue, write, GFP_KERNEL);
+ if (!req)
+ return -EBUSY;
+
+ if (bufflen) {
+ ret = blk_rq_map_kern(stp->device->request_queue, req,
+ buffer, bufflen, GFP_KERNEL);
+ if (ret)
+ goto out;
+ }
+
+ req->cmd_type = REQ_TYPE_BLOCK_PC;
+ req->cmd_flags |= REQ_QUIET;
+
+ req->cmd_len = COMMAND_SIZE(cmd[0]);
+ memcpy(req->cmd, cmd, req->cmd_len);
+
+ req->sense = streq->sense;
+ req->sense_len = 0;
+
+ req->timeout = timeout;
+ req->retries = retries;
+
+ stp->buffer->cmdstat.have_sense = 0;
+ memcpy(streq->cmd, cmd, sizeof(streq->cmd));
+
+ blk_execute_rq(req->q, NULL, req, 1);
+
+ stp->buffer->cmdstat.midlevel_result = streq->result = req->errors;
+ stp->buffer->cmdstat.residual = req->data_len;
+
+ stp->buffer->syscall_result = st_chk_result(stp, streq);
+
+out:
+ blk_put_request(req);
+
+ return ret;
+}
/* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
write has been correct but EOM early warning reached, -EIO if write ended in
--
1.5.6.5
--
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