From ecb0a83e3198f2c1142901687afacbc73602a13b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 18 Oct 2018 22:55:03 +0200 Subject: [PATCH] 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 [rw: Folded in improvements as discussed with hch and jens] Signed-off-by: Richard Weinberger Signed-off-by: Jens Axboe --- arch/um/drivers/ubd_kern.c | 156 +++++++++++++------------------------ 1 file changed, 53 insertions(+), 103 deletions(-) diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index 9cb0cabb4e02..74c002ddc0ce 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -160,12 +160,6 @@ struct ubd { spinlock_t lock; }; -struct ubd_pdu { - struct scatterlist sg[MAX_SG]; - int start_sg, end_sg; - sector_t rq_pos; -}; - #define DEFAULT_COW { \ .file = NULL, \ .fd = -1, \ @@ -197,9 +191,6 @@ static struct proc_dir_entry *proc_ide = NULL; static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd); -static int ubd_init_request(struct blk_mq_tag_set *set, - struct request *req, unsigned int hctx_idx, - unsigned int numa_node); static void make_proc_ide(void) { @@ -895,7 +886,6 @@ static int ubd_disk_register(int major, u64 size, int unit, static const struct blk_mq_ops ubd_mq_ops = { .queue_rq = ubd_queue_rq, - .init_request = ubd_init_request, }; static int ubd_add(int n, char **error_out) @@ -918,7 +908,6 @@ static int ubd_add(int n, char **error_out) ubd_dev->tag_set.queue_depth = 64; ubd_dev->tag_set.numa_node = NUMA_NO_NODE; ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; - ubd_dev->tag_set.cmd_size = sizeof(struct ubd_pdu); ubd_dev->tag_set.driver_data = ubd_dev; ubd_dev->tag_set.nr_hw_queues = 1; @@ -1300,123 +1289,84 @@ static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, req->bitmap_words, bitmap_len); } -/* Called with dev->lock held */ -static void prepare_request(struct request *req, struct io_thread_req *io_req, - unsigned long long offset, int page_offset, - int len, struct page *page) +static int ubd_queue_one_vec(struct blk_mq_hw_ctx *hctx, struct request *req, + u64 off, struct bio_vec *bvec) { - struct gendisk *disk = req->rq_disk; - struct ubd *ubd_dev = disk->private_data; + struct ubd *dev = hctx->queue->queuedata; + struct io_thread_req *io_req; + int ret; + + io_req = kmalloc(sizeof(struct io_thread_req), GFP_ATOMIC); + if (!io_req) + return -ENOMEM; io_req->req = req; - io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd : - ubd_dev->fd; - io_req->fds[1] = ubd_dev->fd; - io_req->cow_offset = -1; - io_req->offset = offset; - io_req->length = len; - io_req->error = 0; - io_req->sector_mask = 0; + if (dev->cow.file) + io_req->fds[0] = dev->cow.fd; + else + io_req->fds[0] = dev->fd; - io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE; - io_req->offsets[0] = 0; - io_req->offsets[1] = ubd_dev->cow.data_offset; - io_req->buffer = page_address(page) + page_offset; - io_req->sectorsize = 1 << 9; + if (req_op(req) == REQ_OP_FLUSH) { + io_req->op = UBD_FLUSH; + } else { + io_req->fds[1] = dev->fd; + io_req->cow_offset = -1; + io_req->offset = off; + io_req->length = bvec->bv_len; + io_req->error = 0; + io_req->sector_mask = 0; - if(ubd_dev->cow.file != NULL) - cowify_req(io_req, ubd_dev->cow.bitmap, - ubd_dev->cow.bitmap_offset, ubd_dev->cow.bitmap_len); + io_req->op = rq_data_dir(req) == READ ? UBD_READ : UBD_WRITE; + io_req->offsets[0] = 0; + io_req->offsets[1] = dev->cow.data_offset; + io_req->buffer = page_address(bvec->bv_page) + bvec->bv_offset; + io_req->sectorsize = 1 << 9; -} + if (dev->cow.file) { + cowify_req(io_req, dev->cow.bitmap, + dev->cow.bitmap_offset, dev->cow.bitmap_len); + } + } -/* Called with dev->lock held */ -static void prepare_flush_request(struct request *req, - struct io_thread_req *io_req) -{ - struct gendisk *disk = req->rq_disk; - struct ubd *ubd_dev = disk->private_data; - - io_req->req = req; - io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd : - ubd_dev->fd; - io_req->op = UBD_FLUSH; -} - -static void submit_request(struct io_thread_req *io_req, struct ubd *dev) -{ - int n = os_write_file(thread_fd, &io_req, - sizeof(io_req)); - - if (n != sizeof(io_req)) { - if (n != -EAGAIN) - pr_err("write to io thread failed: %d\n", -n); - - blk_mq_requeue_request(io_req->req, true); + ret = os_write_file(thread_fd, &io_req, sizeof(io_req)); + if (ret != sizeof(io_req)) { + if (ret != -EAGAIN) + pr_err("write to io thread failed: %d\n", -ret); kfree(io_req); } + + return ret; } static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { struct request *req = bd->rq; - struct ubd *dev = hctx->queue->queuedata; - struct ubd_pdu *pdu = blk_mq_rq_to_pdu(req); - struct io_thread_req *io_req; + int ret = 0; blk_mq_start_request(req); - pdu->rq_pos = blk_rq_pos(req); - pdu->start_sg = 0; - pdu->end_sg = blk_rq_map_sg(req->q, req, pdu->sg); - if (req_op(req) == REQ_OP_FLUSH) { - io_req = kmalloc(sizeof(struct io_thread_req), GFP_ATOMIC); - if (io_req == NULL) { - blk_mq_requeue_request(req, true); - goto done; + ret = ubd_queue_one_vec(hctx, req, 0, NULL); + } else { + struct req_iterator iter; + struct bio_vec bvec; + u64 off = (u64)blk_rq_pos(req) << 9; + + rq_for_each_segment(bvec, req, iter) { + ret = ubd_queue_one_vec(hctx, req, off, &bvec); + if (ret < 0) + goto out; + off += bvec.bv_len; } - prepare_flush_request(req, io_req); - submit_request(io_req, dev); - - goto done; } - - while (pdu->start_sg < pdu->end_sg) { - struct scatterlist *sg = &pdu->sg[pdu->start_sg]; - - io_req = kmalloc(sizeof(struct io_thread_req), - GFP_ATOMIC); - if (io_req == NULL) { - blk_mq_requeue_request(req, true); - goto done; - } - prepare_request(req, io_req, - (unsigned long long)pdu->rq_pos << 9, - sg->offset, sg->length, sg_page(sg)); - - submit_request(io_req, dev); - - pdu->rq_pos += sg->length >> 9; - pdu->start_sg++; +out: + if (ret < 0) { + blk_mq_requeue_request(req, true); } - -done: return BLK_STS_OK; } -static int ubd_init_request(struct blk_mq_tag_set *set, - struct request *req, unsigned int hctx_idx, - unsigned int numa_node) -{ - struct ubd_pdu *pdu = blk_mq_rq_to_pdu(req); - - sg_init_table(pdu->sg, MAX_SG); - - return 0; -} - static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo) { struct ubd *ubd_dev = bdev->bd_disk->private_data;