nvme-pci: create common sgl unmapping helper

This can be reused by metadata sgls once that starts using the blk-mq
dma api.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250813153153.3260897-9-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 111b6bc6c93eb1142484b66883c482795ae14089..e12d47fecc58403ca43fbabb4cf3580000247e6f 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -693,25 +693,23 @@ static void nvme_free_prps(struct request *req)
        mempool_free(iod->dma_vecs, nvmeq->dev->dmavec_mempool);
 }
 
-static void nvme_free_sgls(struct request *req)
+static void nvme_free_sgls(struct request *req, struct nvme_sgl_desc *sge,
+               struct nvme_sgl_desc *sg_list)
 {
-       struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
        struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
-       struct device *dma_dev = nvmeq->dev->dev;
-       dma_addr_t sqe_dma_addr = le64_to_cpu(iod->cmd.common.dptr.sgl.addr);
-       unsigned int sqe_dma_len = le32_to_cpu(iod->cmd.common.dptr.sgl.length);
-       struct nvme_sgl_desc *sg_list = iod->descriptors[0];
        enum dma_data_direction dir = rq_dma_dir(req);
+       unsigned int len = le32_to_cpu(sge->length);
+       struct device *dma_dev = nvmeq->dev->dev;
+       unsigned int i;
 
-       if (iod->nr_descriptors) {
-               unsigned int nr_entries = sqe_dma_len / sizeof(*sg_list), i;
-
-               for (i = 0; i < nr_entries; i++)
-                       dma_unmap_page(dma_dev, le64_to_cpu(sg_list[i].addr),
-                               le32_to_cpu(sg_list[i].length), dir);
-       } else {
-               dma_unmap_page(dma_dev, sqe_dma_addr, sqe_dma_len, dir);
+       if (sge->type == (NVME_SGL_FMT_DATA_DESC << 4)) {
+               dma_unmap_page(dma_dev, le64_to_cpu(sge->addr), len, dir);
+               return;
        }
+
+       for (i = 0; i < len / sizeof(*sg_list); i++)
+               dma_unmap_page(dma_dev, le64_to_cpu(sg_list[i].addr),
+                       le32_to_cpu(sg_list[i].length), dir);
 }
 
 static void nvme_unmap_data(struct request *req)
@@ -731,7 +729,8 @@ static void nvme_unmap_data(struct request *req)
        if (!blk_rq_dma_unmap(req, dma_dev, &iod->dma_state, iod->total_len,
                                iod->flags & IOD_P2P_BUS_ADDR)) {
                if (nvme_pci_cmd_use_sgl(&iod->cmd))
-                       nvme_free_sgls(req);
+                       nvme_free_sgls(req, iod->descriptors[0],
+                                      &iod->cmd.common.dptr.sgl);
                else
                        nvme_free_prps(req);
        }