nvme: refactor nvme_queue_rq

This "backports" the structure I've used for the fabrics driver.  It
mostly started out as a cleanup so that I could actually understand
the code, but I think it also qualifies as a micro-optimization due
to the reduced time we hold q_lock and disable interrupts.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 75970fd..e5f53f1 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -788,19 +788,53 @@ static bool nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod,
        return true;
 }
 
-static void nvme_submit_priv(struct nvme_queue *nvmeq, struct request *req,
-               struct nvme_iod *iod)
+static int nvme_map_data(struct nvme_dev *dev, struct nvme_iod *iod,
+               struct nvme_command *cmnd)
 {
-       struct nvme_command cmnd;
+       struct request *req = iod_get_private(iod);
+       struct request_queue *q = req->q;
+       enum dma_data_direction dma_dir = rq_data_dir(req) ?
+                       DMA_TO_DEVICE : DMA_FROM_DEVICE;
+       int ret = BLK_MQ_RQ_QUEUE_ERROR;
+
+       sg_init_table(iod->sg, req->nr_phys_segments);
+       iod->nents = blk_rq_map_sg(q, req, iod->sg);
+       if (!iod->nents)
+               goto out;
+
+       ret = BLK_MQ_RQ_QUEUE_BUSY;
+       if (!dma_map_sg(dev->dev, iod->sg, iod->nents, dma_dir))
+               goto out;
+
+       if (!nvme_setup_prps(dev, iod, blk_rq_bytes(req)))
+               goto out_unmap;
+
+       ret = BLK_MQ_RQ_QUEUE_ERROR;
+       if (blk_integrity_rq(req)) {
+               if (blk_rq_count_integrity_sg(q, req->bio) != 1)
+                       goto out_unmap;
+
+               sg_init_table(iod->meta_sg, 1);
+               if (blk_rq_map_integrity_sg(q, req->bio, iod->meta_sg) != 1)
+                       goto out_unmap;
 
-       memcpy(&cmnd, req->cmd, sizeof(cmnd));
-       cmnd.rw.command_id = req->tag;
-       if (req->nr_phys_segments) {
-               cmnd.rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
-               cmnd.rw.prp2 = cpu_to_le64(iod->first_dma);
+               if (rq_data_dir(req))
+                       nvme_dif_remap(req, nvme_dif_prep);
+
+               if (!dma_map_sg(dev->dev, iod->meta_sg, 1, dma_dir))
+                       goto out_unmap;
        }
 
-       __nvme_submit_cmd(nvmeq, &cmnd);
+       cmnd->rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+       cmnd->rw.prp2 = cpu_to_le64(iod->first_dma);
+       if (blk_integrity_rq(req))
+               cmnd->rw.metadata = cpu_to_le64(sg_dma_address(iod->meta_sg));
+       return BLK_MQ_RQ_QUEUE_OK;
+
+out_unmap:
+       dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir);
+out:
+       return ret;
 }
 
 /*
@@ -808,46 +842,42 @@ static void nvme_submit_priv(struct nvme_queue *nvmeq, struct request *req,
  * worth having a special pool for these or additional cases to handle freeing
  * the iod.
  */
-static void nvme_submit_discard(struct nvme_queue *nvmeq, struct nvme_ns *ns,
-               struct request *req, struct nvme_iod *iod)
+static int nvme_setup_discard(struct nvme_queue *nvmeq, struct nvme_ns *ns,
+               struct nvme_iod *iod, struct nvme_command *cmnd)
 {
-       struct nvme_dsm_range *range =
-                               (struct nvme_dsm_range *)iod_list(iod)[0];
-       struct nvme_command cmnd;
+       struct request *req = iod_get_private(iod);
+       struct nvme_dsm_range *range;
+
+       range = dma_pool_alloc(nvmeq->dev->prp_small_pool, GFP_ATOMIC,
+                                               &iod->first_dma);
+       if (!range)
+               return BLK_MQ_RQ_QUEUE_BUSY;
+       iod_list(iod)[0] = (__le64 *)range;
+       iod->npages = 0;
 
        range->cattr = cpu_to_le32(0);
        range->nlb = cpu_to_le32(blk_rq_bytes(req) >> ns->lba_shift);
        range->slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
 
-       memset(&cmnd, 0, sizeof(cmnd));
-       cmnd.dsm.opcode = nvme_cmd_dsm;
-       cmnd.dsm.command_id = req->tag;
-       cmnd.dsm.nsid = cpu_to_le32(ns->ns_id);
-       cmnd.dsm.prp1 = cpu_to_le64(iod->first_dma);
-       cmnd.dsm.nr = 0;
-       cmnd.dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);
-
-       __nvme_submit_cmd(nvmeq, &cmnd);
+       memset(cmnd, 0, sizeof(*cmnd));
+       cmnd->dsm.opcode = nvme_cmd_dsm;
+       cmnd->dsm.nsid = cpu_to_le32(ns->ns_id);
+       cmnd->dsm.prp1 = cpu_to_le64(iod->first_dma);
+       cmnd->dsm.nr = 0;
+       cmnd->dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);
+       return BLK_MQ_RQ_QUEUE_OK;
 }
 
-static void nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,
-                                                               int cmdid)
+static void nvme_setup_flush(struct nvme_ns *ns, struct nvme_command *cmnd)
 {
-       struct nvme_command cmnd;
-
-       memset(&cmnd, 0, sizeof(cmnd));
-       cmnd.common.opcode = nvme_cmd_flush;
-       cmnd.common.command_id = cmdid;
-       cmnd.common.nsid = cpu_to_le32(ns->ns_id);
-
-       __nvme_submit_cmd(nvmeq, &cmnd);
+       memset(cmnd, 0, sizeof(*cmnd));
+       cmnd->common.opcode = nvme_cmd_flush;
+       cmnd->common.nsid = cpu_to_le32(ns->ns_id);
 }
 
-static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
-                                                       struct nvme_ns *ns)
+static void nvme_setup_rw(struct nvme_ns *ns, struct request *req,
+               struct nvme_command *cmnd)
 {
-       struct request *req = iod_get_private(iod);
-       struct nvme_command cmnd;
        u16 control = 0;
        u32 dsmgmt = 0;
 
@@ -859,14 +889,12 @@ static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
        if (req->cmd_flags & REQ_RAHEAD)
                dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;
 
-       memset(&cmnd, 0, sizeof(cmnd));
-       cmnd.rw.opcode = (rq_data_dir(req) ? nvme_cmd_write : nvme_cmd_read);
-       cmnd.rw.command_id = req->tag;
-       cmnd.rw.nsid = cpu_to_le32(ns->ns_id);
-       cmnd.rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
-       cmnd.rw.prp2 = cpu_to_le64(iod->first_dma);
-       cmnd.rw.slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
-       cmnd.rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
+       memset(cmnd, 0, sizeof(*cmnd));
+       cmnd->rw.opcode = (rq_data_dir(req) ? nvme_cmd_write : nvme_cmd_read);
+       cmnd->rw.command_id = req->tag;
+       cmnd->rw.nsid = cpu_to_le32(ns->ns_id);
+       cmnd->rw.slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
+       cmnd->rw.length = cpu_to_le16((blk_rq_bytes(req) >> ns->lba_shift) - 1);
 
        if (ns->ms) {
                switch (ns->pi_type) {
@@ -877,23 +905,16 @@ static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
                case NVME_NS_DPS_PI_TYPE2:
                        control |= NVME_RW_PRINFO_PRCHK_GUARD |
                                        NVME_RW_PRINFO_PRCHK_REF;
-                       cmnd.rw.reftag = cpu_to_le32(
+                       cmnd->rw.reftag = cpu_to_le32(
                                        nvme_block_nr(ns, blk_rq_pos(req)));
                        break;
                }
-               if (blk_integrity_rq(req))
-                       cmnd.rw.metadata =
-                               cpu_to_le64(sg_dma_address(iod->meta_sg));
-               else
+               if (!blk_integrity_rq(req))
                        control |= NVME_RW_PRINFO_PRACT;
        }
 
-       cmnd.rw.control = cpu_to_le16(control);
-       cmnd.rw.dsmgmt = cpu_to_le32(dsmgmt);
-
-       __nvme_submit_cmd(nvmeq, &cmnd);
-
-       return 0;
+       cmnd->rw.control = cpu_to_le16(control);
+       cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
 }
 
 /*
@@ -908,7 +929,8 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
        struct request *req = bd->rq;
        struct nvme_cmd_info *cmd = blk_mq_rq_to_pdu(req);
        struct nvme_iod *iod;
-       enum dma_data_direction dma_dir;
+       struct nvme_command cmnd;
+       int ret = BLK_MQ_RQ_QUEUE_OK;
 
        /*
         * If formated with metadata, require the block layer provide a buffer
@@ -928,80 +950,33 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
                return BLK_MQ_RQ_QUEUE_BUSY;
 
        if (req->cmd_flags & REQ_DISCARD) {
-               void *range;
-               /*
-                * We reuse the small pool to allocate the 16-byte range here
-                * as it is not worth having a special pool for these or
-                * additional cases to handle freeing the iod.
-                */
-               range = dma_pool_alloc(dev->prp_small_pool, GFP_ATOMIC,
-                                               &iod->first_dma);
-               if (!range)
-                       goto retry_cmd;
-               iod_list(iod)[0] = (__le64 *)range;
-               iod->npages = 0;
-       } else if (req->nr_phys_segments) {
-               dma_dir = rq_data_dir(req) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
-
-               sg_init_table(iod->sg, req->nr_phys_segments);
-               iod->nents = blk_rq_map_sg(req->q, req, iod->sg);
-               if (!iod->nents)
-                       goto error_cmd;
-
-               if (!dma_map_sg(nvmeq->q_dmadev, iod->sg, iod->nents, dma_dir))
-                       goto retry_cmd;
-
-               if (!nvme_setup_prps(dev, iod, blk_rq_bytes(req))) {
-                       dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir);
-                       goto retry_cmd;
-               }
-               if (blk_integrity_rq(req)) {
-                       if (blk_rq_count_integrity_sg(req->q, req->bio) != 1) {
-                               dma_unmap_sg(dev->dev, iod->sg, iod->nents,
-                                               dma_dir);
-                               goto error_cmd;
-                       }
-
-                       sg_init_table(iod->meta_sg, 1);
-                       if (blk_rq_map_integrity_sg(
-                                       req->q, req->bio, iod->meta_sg) != 1) {
-                               dma_unmap_sg(dev->dev, iod->sg, iod->nents,
-                                               dma_dir);
-                               goto error_cmd;
-                       }
-
-                       if (rq_data_dir(req))
-                               nvme_dif_remap(req, nvme_dif_prep);
+               ret = nvme_setup_discard(nvmeq, ns, iod, &cmnd);
+       } else {
+               if (req->cmd_type == REQ_TYPE_DRV_PRIV)
+                       memcpy(&cmnd, req->cmd, sizeof(cmnd));
+               else if (req->cmd_flags & REQ_FLUSH)
+                       nvme_setup_flush(ns, &cmnd);
+               else
+                       nvme_setup_rw(ns, req, &cmnd);
 
-                       if (!dma_map_sg(nvmeq->q_dmadev, iod->meta_sg, 1, dma_dir)) {
-                               dma_unmap_sg(dev->dev, iod->sg, iod->nents,
-                                               dma_dir);
-                               goto error_cmd;
-                       }
-               }
+               if (req->nr_phys_segments)
+                       ret = nvme_map_data(dev, iod, &cmnd);
        }
 
+       if (ret)
+               goto out;
+
+       cmnd.common.command_id = req->tag;
        nvme_set_info(cmd, iod, req_completion);
-       spin_lock_irq(&nvmeq->q_lock);
-       if (req->cmd_type == REQ_TYPE_DRV_PRIV)
-               nvme_submit_priv(nvmeq, req, iod);
-       else if (req->cmd_flags & REQ_DISCARD)
-               nvme_submit_discard(nvmeq, ns, req, iod);
-       else if (req->cmd_flags & REQ_FLUSH)
-               nvme_submit_flush(nvmeq, ns, req->tag);
-       else
-               nvme_submit_iod(nvmeq, iod, ns);
 
+       spin_lock_irq(&nvmeq->q_lock);
+       __nvme_submit_cmd(nvmeq, &cmnd);
        nvme_process_cq(nvmeq);
        spin_unlock_irq(&nvmeq->q_lock);
        return BLK_MQ_RQ_QUEUE_OK;
-
- error_cmd:
-       nvme_free_iod(dev, iod);
-       return BLK_MQ_RQ_QUEUE_ERROR;
- retry_cmd:
+out:
        nvme_free_iod(dev, iod);
-       return BLK_MQ_RQ_QUEUE_BUSY;
+       return ret;
 }
 
 static void __nvme_process_cq(struct nvme_queue *nvmeq, unsigned int *tag)