NVMe: Add nvme_setup_prps()

Generalise the code from nvme_identify() that sets PRP1 & PRP2 so that
it's usable for commands sent by nvme_submit_bio_queue().

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

1 files changed, 46 insertions, 24 deletions

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index c0ef1dd1cc90..1e57737b1760 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -240,6 +240,36 @@ static void bio_completion(struct nvme_queue *nvmeq, void *ctx,
         bio_endio(bio, status ? -EIO : 0);
 }
 
+/* length is in bytes */
+static void nvme_setup_prps(struct nvme_common_command *cmd,
+                                        struct scatterlist *sg, int length)
+{
+        int dma_len = sg_dma_len(sg);
+        u64 dma_addr = sg_dma_address(sg);
+        int offset = offset_in_page(dma_addr);
+
+        cmd->prp1 = cpu_to_le64(dma_addr);
+        length -= (PAGE_SIZE - offset);
+        if (length <= 0)
+                return;
+
+        dma_len -= (PAGE_SIZE - offset);
+        if (dma_len) {
+                dma_addr += (PAGE_SIZE - offset);
+        } else {
+                sg = sg_next(sg);
+                dma_addr = sg_dma_address(sg);
+                dma_len = sg_dma_len(sg);
+        }
+
+        if (length <= PAGE_SIZE) {
+                cmd->prp2 = cpu_to_le64(dma_addr);
+                return;
+        }
+
+        /* XXX: support PRP lists */
+}
+
 static int nvme_map_bio(struct device *dev, struct nvme_req_info *info,
                 struct bio *bio, enum dma_data_direction dma_dir, int psegs)
 {
@@ -261,7 +291,7 @@ static int nvme_map_bio(struct device *dev, struct nvme_req_info *info,
 static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
                                                                 struct bio *bio)
 {
-        struct nvme_rw_command *cmnd;
+        struct nvme_command *cmnd;
         struct nvme_req_info *info;
         enum dma_data_direction dma_dir;
         int cmdid;
@@ -290,27 +320,26 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
                 dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;
 
         spin_lock_irqsave(&nvmeq->q_lock, flags);
-        cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail].rw;
+        cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
 
         if (bio_data_dir(bio)) {
-                cmnd->opcode = nvme_cmd_write;
+                cmnd->rw.opcode = nvme_cmd_write;
                 dma_dir = DMA_TO_DEVICE;
         } else {
-                cmnd->opcode = nvme_cmd_read;
+                cmnd->rw.opcode = nvme_cmd_read;
                 dma_dir = DMA_FROM_DEVICE;
         }
 
         nvme_map_bio(nvmeq->q_dmadev, info, bio, dma_dir, psegs);
 
-        cmnd->flags = 1;
-        cmnd->command_id = cmdid;
-        cmnd->nsid = cpu_to_le32(ns->ns_id);
-        cmnd->prp1 = cpu_to_le64(sg_phys(info->sg));
-        /* XXX: Support more than one PRP */
-        cmnd->slba = cpu_to_le64(bio->bi_sector >> (ns->lba_shift - 9));
-        cmnd->length = cpu_to_le16((bio->bi_size >> ns->lba_shift) - 1);
-        cmnd->control = cpu_to_le16(control);
-        cmnd->dsmgmt = cpu_to_le32(dsmgmt);
+        cmnd->rw.flags = 1;
+        cmnd->rw.command_id = cmdid;
+        cmnd->rw.nsid = cpu_to_le32(ns->ns_id);
+        nvme_setup_prps(&cmnd->common, info->sg, bio->bi_size);
+        cmnd->rw.slba = cpu_to_le64(bio->bi_sector >> (ns->lba_shift - 9));
+        cmnd->rw.length = cpu_to_le16((bio->bi_size >> ns->lba_shift) - 1);
+        cmnd->rw.control = cpu_to_le16(control);
+        cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
 
         writel(nvmeq->sq_tail, nvmeq->q_db);
         if (++nvmeq->sq_tail == nvmeq->q_depth)
@@ -667,8 +696,9 @@ static int nvme_identify(struct nvme_ns *ns, unsigned long addr, int cns)
                 goto put_pages;
         }
         sg_init_table(sg, count);
-        for (i = 0; i < count; i++)
-                sg_set_page(&sg[i], pages[i], PAGE_SIZE, 0);
+        sg_set_page(&sg[0], pages[0], PAGE_SIZE - offset, offset);
+        if (count > 1)
+                sg_set_page(&sg[1], pages[1], offset, 0);
         nents = dma_map_sg(&dev->pci_dev->dev, sg, count, DMA_FROM_DEVICE);
         if (!nents)
                 goto put_pages;
@@ -676,15 +706,7 @@ static int nvme_identify(struct nvme_ns *ns, unsigned long addr, int cns)
         memset(&c, 0, sizeof(c));
         c.identify.opcode = nvme_admin_identify;
         c.identify.nsid = cns ? 0 : cpu_to_le32(ns->ns_id);
-        c.identify.prp1 = cpu_to_le64(sg_dma_address(&sg[0]) + offset);
-        if (count > 1) {
-                u64 dma_addr;
-                if (nents > 1)
-                        dma_addr = sg_dma_address(&sg[1]);
-                else
-                        dma_addr = sg_dma_address(&sg[0]) + PAGE_SIZE;
-                c.identify.prp2 = cpu_to_le64(dma_addr);
-        }
+        nvme_setup_prps(&c.common, sg, 4096);
         c.identify.cns = cpu_to_le32(cns);
 
         err = nvme_submit_admin_cmd(dev, &c, NULL);