+static int osst_execute(struct osst_request *SRpnt, const unsigned char *cmd,
+ int cmd_len, int data_direction, void *buffer, unsigned bufflen,
+ int use_sg, int timeout, int retries)
+{
+ struct request *req;
+ struct page **pages = NULL;
+ 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;
+
+ SRpnt->bio = NULL;
+
+ if (use_sg) {
+ struct scatterlist *sg, *sgl = (struct scatterlist *)buffer;
+ int i;
+
+ pages = kzalloc(use_sg * sizeof(struct page *), GFP_KERNEL);
+ if (!pages)
+ goto free_req;
+
+ for_each_sg(sgl, sg, use_sg, i)
+ pages[i] = sg_page(sg);
+
+ mdata->null_mapped = 1;
+
+ mdata->page_order = get_order(sgl[0].length);
+ mdata->nr_entries =
+ DIV_ROUND_UP(bufflen, PAGE_SIZE << mdata->page_order);
+ mdata->offset = 0;
+
+ err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen, GFP_KERNEL);
+ if (err) {
+ kfree(pages);
+ goto free_req;
+ }
+ SRpnt->bio = req->bio;
+ mdata->pages = pages;
+
+ } else if (bufflen) {
+ err = blk_rq_map_kern(req->q, req, buffer, bufflen, GFP_KERNEL);
+ if (err)
+ goto free_req;
+ }
+
+ req->cmd_len = cmd_len;
+ memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after 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, osst_end_async);
+ return 0;
+free_req:
+ blk_put_request(req);
+ return DRIVER_ERROR << 24;
+}
+