ubd: remove use of blk_rq_map_sg
There is no good reason to create a scatterlist in the ubd driver, it can just iterate the request directly. Signed-off-by: Christoph Hellwig <hch@lst.de> [rw: Folded in improvements as discussed with hch and jens] Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig
Jens Axboe
parent
6956b95693
commit
ecb0a83e31
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@ -160,12 +160,6 @@ struct ubd {
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spinlock_t lock;
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};
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struct ubd_pdu {
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struct scatterlist sg[MAX_SG];
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int start_sg, end_sg;
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sector_t rq_pos;
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};
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#define DEFAULT_COW { \
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.file = NULL, \
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.fd = -1, \
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@ -197,9 +191,6 @@ static struct proc_dir_entry *proc_ide = NULL;
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static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
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const struct blk_mq_queue_data *bd);
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static int ubd_init_request(struct blk_mq_tag_set *set,
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struct request *req, unsigned int hctx_idx,
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unsigned int numa_node);
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static void make_proc_ide(void)
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{
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@ -895,7 +886,6 @@ static int ubd_disk_register(int major, u64 size, int unit,
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static const struct blk_mq_ops ubd_mq_ops = {
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.queue_rq = ubd_queue_rq,
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.init_request = ubd_init_request,
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};
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static int ubd_add(int n, char **error_out)
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@ -918,7 +908,6 @@ static int ubd_add(int n, char **error_out)
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ubd_dev->tag_set.queue_depth = 64;
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ubd_dev->tag_set.numa_node = NUMA_NO_NODE;
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ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
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ubd_dev->tag_set.cmd_size = sizeof(struct ubd_pdu);
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ubd_dev->tag_set.driver_data = ubd_dev;
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ubd_dev->tag_set.nr_hw_queues = 1;
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@ -1300,123 +1289,84 @@ static void cowify_req(struct io_thread_req *req, unsigned long *bitmap,
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req->bitmap_words, bitmap_len);
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}
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/* Called with dev->lock held */
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static void prepare_request(struct request *req, struct io_thread_req *io_req,
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unsigned long long offset, int page_offset,
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int len, struct page *page)
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static int ubd_queue_one_vec(struct blk_mq_hw_ctx *hctx, struct request *req,
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u64 off, struct bio_vec *bvec)
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{
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struct gendisk *disk = req->rq_disk;
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struct ubd *ubd_dev = disk->private_data;
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struct ubd *dev = hctx->queue->queuedata;
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struct io_thread_req *io_req;
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int ret;
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io_req = kmalloc(sizeof(struct io_thread_req), GFP_ATOMIC);
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if (!io_req)
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return -ENOMEM;
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io_req->req = req;
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io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd :
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ubd_dev->fd;
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io_req->fds[1] = ubd_dev->fd;
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io_req->cow_offset = -1;
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io_req->offset = offset;
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io_req->length = len;
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io_req->error = 0;
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io_req->sector_mask = 0;
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if (dev->cow.file)
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io_req->fds[0] = dev->cow.fd;
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else
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io_req->fds[0] = dev->fd;
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io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE;
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io_req->offsets[0] = 0;
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io_req->offsets[1] = ubd_dev->cow.data_offset;
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io_req->buffer = page_address(page) + page_offset;
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io_req->sectorsize = 1 << 9;
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if (req_op(req) == REQ_OP_FLUSH) {
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io_req->op = UBD_FLUSH;
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} else {
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io_req->fds[1] = dev->fd;
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io_req->cow_offset = -1;
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io_req->offset = off;
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io_req->length = bvec->bv_len;
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io_req->error = 0;
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io_req->sector_mask = 0;
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if(ubd_dev->cow.file != NULL)
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cowify_req(io_req, ubd_dev->cow.bitmap,
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ubd_dev->cow.bitmap_offset, ubd_dev->cow.bitmap_len);
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io_req->op = rq_data_dir(req) == READ ? UBD_READ : UBD_WRITE;
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io_req->offsets[0] = 0;
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io_req->offsets[1] = dev->cow.data_offset;
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io_req->buffer = page_address(bvec->bv_page) + bvec->bv_offset;
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io_req->sectorsize = 1 << 9;
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}
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if (dev->cow.file) {
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cowify_req(io_req, dev->cow.bitmap,
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dev->cow.bitmap_offset, dev->cow.bitmap_len);
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}
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}
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/* Called with dev->lock held */
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static void prepare_flush_request(struct request *req,
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struct io_thread_req *io_req)
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{
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struct gendisk *disk = req->rq_disk;
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struct ubd *ubd_dev = disk->private_data;
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io_req->req = req;
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io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd :
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ubd_dev->fd;
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io_req->op = UBD_FLUSH;
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}
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static void submit_request(struct io_thread_req *io_req, struct ubd *dev)
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{
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int n = os_write_file(thread_fd, &io_req,
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sizeof(io_req));
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if (n != sizeof(io_req)) {
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if (n != -EAGAIN)
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pr_err("write to io thread failed: %d\n", -n);
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blk_mq_requeue_request(io_req->req, true);
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ret = os_write_file(thread_fd, &io_req, sizeof(io_req));
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if (ret != sizeof(io_req)) {
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if (ret != -EAGAIN)
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pr_err("write to io thread failed: %d\n", -ret);
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kfree(io_req);
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}
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return ret;
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}
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static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
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const struct blk_mq_queue_data *bd)
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{
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struct request *req = bd->rq;
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struct ubd *dev = hctx->queue->queuedata;
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struct ubd_pdu *pdu = blk_mq_rq_to_pdu(req);
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struct io_thread_req *io_req;
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int ret = 0;
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blk_mq_start_request(req);
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pdu->rq_pos = blk_rq_pos(req);
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pdu->start_sg = 0;
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pdu->end_sg = blk_rq_map_sg(req->q, req, pdu->sg);
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if (req_op(req) == REQ_OP_FLUSH) {
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io_req = kmalloc(sizeof(struct io_thread_req), GFP_ATOMIC);
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if (io_req == NULL) {
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blk_mq_requeue_request(req, true);
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goto done;
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ret = ubd_queue_one_vec(hctx, req, 0, NULL);
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} else {
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struct req_iterator iter;
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struct bio_vec bvec;
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u64 off = (u64)blk_rq_pos(req) << 9;
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rq_for_each_segment(bvec, req, iter) {
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ret = ubd_queue_one_vec(hctx, req, off, &bvec);
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if (ret < 0)
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goto out;
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off += bvec.bv_len;
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}
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prepare_flush_request(req, io_req);
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submit_request(io_req, dev);
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goto done;
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}
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while (pdu->start_sg < pdu->end_sg) {
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struct scatterlist *sg = &pdu->sg[pdu->start_sg];
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io_req = kmalloc(sizeof(struct io_thread_req),
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GFP_ATOMIC);
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if (io_req == NULL) {
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blk_mq_requeue_request(req, true);
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goto done;
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}
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prepare_request(req, io_req,
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(unsigned long long)pdu->rq_pos << 9,
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sg->offset, sg->length, sg_page(sg));
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submit_request(io_req, dev);
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pdu->rq_pos += sg->length >> 9;
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pdu->start_sg++;
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out:
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if (ret < 0) {
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blk_mq_requeue_request(req, true);
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}
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done:
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return BLK_STS_OK;
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}
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static int ubd_init_request(struct blk_mq_tag_set *set,
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struct request *req, unsigned int hctx_idx,
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unsigned int numa_node)
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{
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struct ubd_pdu *pdu = blk_mq_rq_to_pdu(req);
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sg_init_table(pdu->sg, MAX_SG);
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return 0;
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}
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static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
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{
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struct ubd *ubd_dev = bdev->bd_disk->private_data;
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