-struct scsi_io_context {
- void *data;
- void (*done)(void *data, char *sense, int result, int resid);
- char sense[SCSI_SENSE_BUFFERSIZE];
-};
-
-static struct kmem_cache *scsi_io_context_cache;
-
-static void scsi_end_async(struct request *req, int uptodate)
-{
- struct scsi_io_context *sioc = req->end_io_data;
-
- if (sioc->done)
- sioc->done(sioc->data, sioc->sense, req->errors, req->data_len);
-
- kmem_cache_free(scsi_io_context_cache, sioc);
- __blk_put_request(req->q, req);
-}
-
-static int scsi_merge_bio(struct request *rq, struct bio *bio)
-{
- struct request_queue *q = rq->q;
-
- bio->bi_flags &= ~(1 << BIO_SEG_VALID);
- if (rq_data_dir(rq) == WRITE)
- bio->bi_rw |= (1 << BIO_RW);
- blk_queue_bounce(q, &bio);
-
- return blk_rq_append_bio(q, rq, bio);
-}
-
-static void scsi_bi_endio(struct bio *bio, int error)
-{
- bio_put(bio);
-}
-
-/**
- * scsi_req_map_sg - map a scatterlist into a request
- * @rq: request to fill
- * @sgl: scatterlist
- * @nsegs: number of elements
- * @bufflen: len of buffer
- * @gfp: memory allocation flags
- *
- * scsi_req_map_sg maps a scatterlist into a request so that the
- * request can be sent to the block layer. We do not trust the scatterlist
- * sent to use, as some ULDs use that struct to only organize the pages.
- */
-static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
- int nsegs, unsigned bufflen, gfp_t gfp)
-{
- struct request_queue *q = rq->q;
- int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
- unsigned int data_len = bufflen, len, bytes, off;
- struct scatterlist *sg;
- struct page *page;
- struct bio *bio = NULL;
- int i, err, nr_vecs = 0;
-
- for_each_sg(sgl, sg, nsegs, i) {
- page = sg_page(sg);
- off = sg->offset;
- len = sg->length;
-
- while (len > 0 && data_len > 0) {
- /*
- * sg sends a scatterlist that is larger than
- * the data_len it wants transferred for certain
- * IO sizes
- */
- bytes = min_t(unsigned int, len, PAGE_SIZE - off);
- bytes = min(bytes, data_len);
-
- if (!bio) {
- nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
- nr_pages -= nr_vecs;
-
- bio = bio_alloc(gfp, nr_vecs);
- if (!bio) {
- err = -ENOMEM;
- goto free_bios;
- }
- bio->bi_end_io = scsi_bi_endio;
- }
-
- if (bio_add_pc_page(q, bio, page, bytes, off) !=
- bytes) {
- bio_put(bio);
- err = -EINVAL;
- goto free_bios;
- }
-
- if (bio->bi_vcnt >= nr_vecs) {
- err = scsi_merge_bio(rq, bio);
- if (err) {
- bio_endio(bio, 0);
- goto free_bios;
- }
- bio = NULL;
- }
-
- page++;
- len -= bytes;
- data_len -=bytes;
- off = 0;
- }
- }
-
- rq->buffer = rq->data = NULL;
- rq->data_len = bufflen;
- return 0;
-
-free_bios:
- while ((bio = rq->bio) != NULL) {
- rq->bio = bio->bi_next;
- /*
- * call endio instead of bio_put incase it was bounced
- */
- bio_endio(bio, 0);
- }
-
- return err;
-}
-
-/**
- * scsi_execute_async - insert request
- * @sdev: scsi device
- * @cmd: scsi command
- * @cmd_len: length of scsi cdb
- * @data_direction: DMA_TO_DEVICE, DMA_FROM_DEVICE, or DMA_NONE
- * @buffer: data buffer (this can be a kernel buffer or scatterlist)
- * @bufflen: len of buffer
- * @use_sg: if buffer is a scatterlist this is the number of elements
- * @timeout: request timeout in seconds
- * @retries: number of times to retry request
- * @privdata: data passed to done()
- * @done: callback function when done
- * @gfp: memory allocation flags
- */
-int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
- int cmd_len, int data_direction, void *buffer, unsigned bufflen,
- int use_sg, int timeout, int retries, void *privdata,
- void (*done)(void *, char *, int, int), gfp_t gfp)
-{
- struct request *req;
- struct scsi_io_context *sioc;
- int err = 0;
- int write = (data_direction == DMA_TO_DEVICE);
-
- sioc = kmem_cache_zalloc(scsi_io_context_cache, gfp);
- if (!sioc)
- return DRIVER_ERROR << 24;
-
- req = blk_get_request(sdev->request_queue, write, gfp);
- if (!req)
- goto free_sense;
- req->cmd_type = REQ_TYPE_BLOCK_PC;
- req->cmd_flags |= REQ_QUIET;
-
- if (use_sg)
- err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
- else if (bufflen)
- err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
-
- 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 = sioc->sense;
- req->sense_len = 0;
- req->timeout = timeout;
- req->retries = retries;
- req->end_io_data = sioc;
-
- sioc->data = privdata;
- sioc->done = done;
-
- blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async);
- return 0;
-
-free_req:
- blk_put_request(req);
-free_sense:
- kmem_cache_free(scsi_io_context_cache, sioc);
- return DRIVER_ERROR << 24;
-}
-EXPORT_SYMBOL_GPL(scsi_execute_async);
-
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff