* barrier
*/
rq->cmd_type = REQ_TYPE_SPECIAL;
- rq->cmd_flags |= REQ_SOFTBARRIER;
rq->special = data;
if (bio_failfast_driver(bio))
req->cmd_flags |= REQ_FAILFAST_DRIVER;
- /*
- * REQ_BARRIER implies no merging, but lets make it explicit
- */
if (unlikely(bio_discard(bio))) {
req->cmd_flags |= REQ_DISCARD;
if (bio_barrier(bio))
req->cmd_flags |= REQ_SOFTBARRIER;
req->q->prepare_discard_fn(req->q, req);
} else if (unlikely(bio_barrier(bio)))
- req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
+ req->cmd_flags |= REQ_HARDBARRIER;
if (bio_sync(bio))
req->cmd_flags |= REQ_RW_SYNC;
}
/**
+ * blk_rq_bytes - Returns bytes left to complete in the entire request
+ * @rq: the request being processed
+ **/
+unsigned int blk_rq_bytes(struct request *rq)
+{
+ if (blk_fs_request(rq))
+ return rq->hard_nr_sectors << 9;
+
+ return rq->data_len;
+}
+EXPORT_SYMBOL_GPL(blk_rq_bytes);
+
+/**
+ * blk_rq_cur_bytes - Returns bytes left to complete in the current segment
+ * @rq: the request being processed
+ **/
+unsigned int blk_rq_cur_bytes(struct request *rq)
+{
+ if (blk_fs_request(rq))
+ return rq->current_nr_sectors << 9;
+
+ if (rq->bio)
+ return rq->bio->bi_size;
+
+ return rq->data_len;
+}
+EXPORT_SYMBOL_GPL(blk_rq_cur_bytes);
+
+struct request *elv_next_request(struct request_queue *q)
+{
+ struct request *rq;
+ int ret;
+
+ while ((rq = __elv_next_request(q)) != NULL) {
+ if (!(rq->cmd_flags & REQ_STARTED)) {
+ /*
+ * This is the first time the device driver
+ * sees this request (possibly after
+ * requeueing). Notify IO scheduler.
+ */
+ if (blk_sorted_rq(rq))
+ elv_activate_rq(q, rq);
+
+ /*
+ * just mark as started even if we don't start
+ * it, a request that has been delayed should
+ * not be passed by new incoming requests
+ */
+ rq->cmd_flags |= REQ_STARTED;
+ trace_block_rq_issue(q, rq);
+ }
+
+ if (!q->boundary_rq || q->boundary_rq == rq) {
+ q->end_sector = rq_end_sector(rq);
+ q->boundary_rq = NULL;
+ }
+
+ if (rq->cmd_flags & REQ_DONTPREP)
+ break;
+
+ if (q->dma_drain_size && rq->data_len) {
+ /*
+ * make sure space for the drain appears we
+ * know we can do this because max_hw_segments
+ * has been adjusted to be one fewer than the
+ * device can handle
+ */
+ rq->nr_phys_segments++;
+ }
+
+ if (!q->prep_rq_fn)
+ break;
+
+ ret = q->prep_rq_fn(q, rq);
+ if (ret == BLKPREP_OK) {
+ break;
+ } else if (ret == BLKPREP_DEFER) {
+ /*
+ * the request may have been (partially) prepped.
+ * we need to keep this request in the front to
+ * avoid resource deadlock. REQ_STARTED will
+ * prevent other fs requests from passing this one.
+ */
+ if (q->dma_drain_size && rq->data_len &&
+ !(rq->cmd_flags & REQ_DONTPREP)) {
+ /*
+ * remove the space for the drain we added
+ * so that we don't add it again
+ */
+ --rq->nr_phys_segments;
+ }
+
+ rq = NULL;
+ break;
+ } else if (ret == BLKPREP_KILL) {
+ rq->cmd_flags |= REQ_QUIET;
+ __blk_end_request(rq, -EIO, blk_rq_bytes(rq));
+ } else {
+ printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
+ break;
+ }
+ }
+
+ return rq;
+}
+EXPORT_SYMBOL(elv_next_request);
+
+void elv_dequeue_request(struct request_queue *q, struct request *rq)
+{
+ BUG_ON(list_empty(&rq->queuelist));
+ BUG_ON(ELV_ON_HASH(rq));
+
+ list_del_init(&rq->queuelist);
+
+ /*
+ * the time frame between a request being removed from the lists
+ * and to it is freed is accounted as io that is in progress at
+ * the driver side.
+ */
+ if (blk_account_rq(rq))
+ q->in_flight++;
+}
+
+/**
* __end_that_request_first - end I/O on a request
* @req: the request being processed
* @error: %0 for success, < %0 for error
return 1;
}
+static int end_that_request_data(struct request *rq, int error,
+ unsigned int nr_bytes, unsigned int bidi_bytes)
+{
+ if (rq->bio) {
+ if (__end_that_request_first(rq, error, nr_bytes))
+ return 1;
+
+ /* Bidi request must be completed as a whole */
+ if (blk_bidi_rq(rq) &&
+ __end_that_request_first(rq->next_rq, error, bidi_bytes))
+ return 1;
+ }
+
+ return 0;
+}
+
/*
* queue lock must be held
*/
}
/**
- * blk_rq_bytes - Returns bytes left to complete in the entire request
- * @rq: the request being processed
- **/
-unsigned int blk_rq_bytes(struct request *rq)
-{
- if (blk_fs_request(rq))
- return rq->hard_nr_sectors << 9;
-
- return rq->data_len;
-}
-EXPORT_SYMBOL_GPL(blk_rq_bytes);
-
-/**
- * blk_rq_cur_bytes - Returns bytes left to complete in the current segment
- * @rq: the request being processed
- **/
-unsigned int blk_rq_cur_bytes(struct request *rq)
-{
- if (blk_fs_request(rq))
- return rq->current_nr_sectors << 9;
-
- if (rq->bio)
- return rq->bio->bi_size;
-
- return rq->data_len;
-}
-EXPORT_SYMBOL_GPL(blk_rq_cur_bytes);
-
-/**
- * end_request - end I/O on the current segment of the request
- * @req: the request being processed
- * @uptodate: error value or %0/%1 uptodate flag
- *
- * Description:
- * Ends I/O on the current segment of a request. If that is the only
- * remaining segment, the request is also completed and freed.
- *
- * This is a remnant of how older block drivers handled I/O completions.
- * Modern drivers typically end I/O on the full request in one go, unless
- * they have a residual value to account for. For that case this function
- * isn't really useful, unless the residual just happens to be the
- * full current segment. In other words, don't use this function in new
- * code. Use blk_end_request() or __blk_end_request() to end a request.
- **/
-void end_request(struct request *req, int uptodate)
-{
- int error = 0;
-
- if (uptodate <= 0)
- error = uptodate ? uptodate : -EIO;
-
- __blk_end_request(req, error, req->hard_cur_sectors << 9);
-}
-EXPORT_SYMBOL(end_request);
-
-static int end_that_request_data(struct request *rq, int error,
- unsigned int nr_bytes, unsigned int bidi_bytes)
-{
- if (rq->bio) {
- if (__end_that_request_first(rq, error, nr_bytes))
- return 1;
-
- /* Bidi request must be completed as a whole */
- if (blk_bidi_rq(rq) &&
- __end_that_request_first(rq->next_rq, error, bidi_bytes))
- return 1;
- }
-
- return 0;
-}
-
-/**
* blk_end_io - Generic end_io function to complete a request.
* @rq: the request being processed
* @error: %0 for success, < %0 for error
EXPORT_SYMBOL_GPL(blk_end_bidi_request);
/**
+ * end_request - end I/O on the current segment of the request
+ * @req: the request being processed
+ * @uptodate: error value or %0/%1 uptodate flag
+ *
+ * Description:
+ * Ends I/O on the current segment of a request. If that is the only
+ * remaining segment, the request is also completed and freed.
+ *
+ * This is a remnant of how older block drivers handled I/O completions.
+ * Modern drivers typically end I/O on the full request in one go, unless
+ * they have a residual value to account for. For that case this function
+ * isn't really useful, unless the residual just happens to be the
+ * full current segment. In other words, don't use this function in new
+ * code. Use blk_end_request() or __blk_end_request() to end a request.
+ **/
+void end_request(struct request *req, int uptodate)
+{
+ int error = 0;
+
+ if (uptodate <= 0)
+ error = uptodate ? uptodate : -EIO;
+
+ __blk_end_request(req, error, req->hard_cur_sectors << 9);
+}
+EXPORT_SYMBOL(end_request);
+
+/**
* blk_update_request - Special helper function for request stacking drivers
* @rq: the request being processed
* @error: %0 for success, < %0 for error
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff