[PATCH 16/16] hw/block/nvme: use preallocated qsg/iov in nvme_dma_prp

[Klaus Jensen <its@irrelevant.dk>]

From: Klaus Jensen <k.jensen@samsung.com>

Since clean up of the request qsg/iov is now always done post-use, there
is no need to use a stack-allocated qsg/iov in nvme_dma_prp.

Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
Acked-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 hw/block/nvme.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 0b3dceccc89b..b6da5a9f3fc6 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -381,45 +381,39 @@ static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
                              uint64_t prp1, uint64_t prp2, DMADirection dir,
                              NvmeRequest *req)
 {
-    QEMUSGList qsg;
-    QEMUIOVector iov;
     uint16_t status = NVME_SUCCESS;
 
-    status = nvme_map_prp(n, &qsg, &iov, prp1, prp2, len, req);
+    status = nvme_map_prp(n, &req->qsg, &req->iov, prp1, prp2, len, req);
     if (status) {
         return status;
     }
 
-    if (qsg.nsg > 0) {
+    if (req->qsg.nsg > 0) {
         uint64_t residual;
 
         if (dir == DMA_DIRECTION_TO_DEVICE) {
-            residual = dma_buf_write(ptr, len, &qsg);
+            residual = dma_buf_write(ptr, len, &req->qsg);
         } else {
-            residual = dma_buf_read(ptr, len, &qsg);
+            residual = dma_buf_read(ptr, len, &req->qsg);
         }
 
         if (unlikely(residual)) {
             trace_pci_nvme_err_invalid_dma();
             status = NVME_INVALID_FIELD | NVME_DNR;
         }
-
-        qemu_sglist_destroy(&qsg);
     } else {
         size_t bytes;
 
         if (dir == DMA_DIRECTION_TO_DEVICE) {
-            bytes = qemu_iovec_to_buf(&iov, 0, ptr, len);
+            bytes = qemu_iovec_to_buf(&req->iov, 0, ptr, len);
         } else {
-            bytes = qemu_iovec_from_buf(&iov, 0, ptr, len);
+            bytes = qemu_iovec_from_buf(&req->iov, 0, ptr, len);
         }
 
         if (unlikely(bytes != len)) {
             trace_pci_nvme_err_invalid_dma();
             status = NVME_INVALID_FIELD | NVME_DNR;
         }
-
-        qemu_iovec_destroy(&iov);
     }
 
     return status;
-- 
2.27.0