NVMe: Unify SQ entry writing and doorbell ringing

This patch changes sq_cmd writers to instead create their command on
the stack. __nvme_submit_cmd copies the sq entry to the queue and writes
the doorbell.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 35 insertions, 45 deletions

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index d844ec4a2b85..e09ad6cc6dec 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -730,18 +730,16 @@ static int nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod,
 static void nvme_submit_priv(struct nvme_queue *nvmeq, struct request *req,
                 struct nvme_iod *iod)
 {
-        struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
+        struct nvme_command cmnd;
 
-        memcpy(cmnd, req->cmd, sizeof(struct nvme_command));
-        cmnd->rw.command_id = req->tag;
+        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);
+                cmnd.rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+                cmnd.rw.prp2 = cpu_to_le64(iod->first_dma);
         }
 
-        if (++nvmeq->sq_tail == nvmeq->q_depth)
-                nvmeq->sq_tail = 0;
-        writel(nvmeq->sq_tail, nvmeq->q_db);
+        __nvme_submit_cmd(nvmeq, &cmnd);
 }
 
 /*
@@ -754,45 +752,41 @@ static void nvme_submit_discard(struct nvme_queue *nvmeq, struct nvme_ns *ns,
 {
         struct nvme_dsm_range *range =
                                 (struct nvme_dsm_range *)iod_list(iod)[0];
-        struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
+        struct nvme_command cmnd;
 
         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);
+        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);
 
-        if (++nvmeq->sq_tail == nvmeq->q_depth)
-                nvmeq->sq_tail = 0;
-        writel(nvmeq->sq_tail, nvmeq->q_db);
+        __nvme_submit_cmd(nvmeq, &cmnd);
 }
 
 static void nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,
                                                                 int cmdid)
 {
-        struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
+        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);
+        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);
 
-        if (++nvmeq->sq_tail == nvmeq->q_depth)
-                nvmeq->sq_tail = 0;
-        writel(nvmeq->sq_tail, nvmeq->q_db);
+        __nvme_submit_cmd(nvmeq, &cmnd);
 }
 
 static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
                                                         struct nvme_ns *ns)
 {
         struct request *req = iod_get_private(iod);
-        struct nvme_command *cmnd;
+        struct nvme_command cmnd;
         u16 control = 0;
         u32 dsmgmt = 0;
 
@@ -804,19 +798,17 @@ 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;
 
-        cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
-        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.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);
 
         if (blk_integrity_rq(req)) {
-                cmnd->rw.metadata = cpu_to_le64(sg_dma_address(iod->meta_sg));
+                cmnd.rw.metadata = cpu_to_le64(sg_dma_address(iod->meta_sg));
                 switch (ns->pi_type) {
                 case NVME_NS_DPS_PI_TYPE3:
                         control |= NVME_RW_PRINFO_PRCHK_GUARD;
@@ -825,19 +817,17 @@ 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;
                 }
         } else if (ns->ms)
                 control |= NVME_RW_PRINFO_PRACT;
 
-        cmnd->rw.control = cpu_to_le16(control);
-        cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
+        cmnd.rw.control = cpu_to_le16(control);
+        cmnd.rw.dsmgmt = cpu_to_le32(dsmgmt);
 
-        if (++nvmeq->sq_tail == nvmeq->q_depth)
-                nvmeq->sq_tail = 0;
-        writel(nvmeq->sq_tail, nvmeq->q_db);
+        __nvme_submit_cmd(nvmeq, &cmnd);
 
         return 0;
 }