Re: [PATCH v5 18/26] nvme: use preallocated qsg/iov in nvme_dma_prp

[Maxim Levitsky]

On Tue, 2020-02-04 at 10:52 +0100, Klaus Jensen wrote:
> Since clean up of the request qsg/iov has been moved to the common
> nvme_enqueue_req_completion function, there is no need to use a
> stack allocated qsg/iov in nvme_dma_prp.
> 
> Signed-off-by: Klaus Jensen 
> ---
>  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 e97da35c4ca1..f8c81b9e2202 100644
> --- a/hw/block/nvme.c
> +++ b/hw/block/nvme.c
> @@ -298,23 +298,21 @@ unmap:
>  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;
>  size_t bytes;
>  
> -status = nvme_map_prp(n, , , prp1, prp2, len, req);
> +status = nvme_map_prp(n, >qsg, >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, );
> +residual = dma_buf_write(ptr, len, >qsg);
>  } else {
> -residual = dma_buf_read(ptr, len, );
> +residual = dma_buf_read(ptr, len, >qsg);
>  }
>  
>  if (unlikely(residual)) {
> @@ -322,15 +320,13 @@ static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, 
> uint32_t len,
>  status = NVME_INVALID_FIELD | NVME_DNR;
>  }
>  
> -qemu_sglist_destroy();
> -
>  return status;
>  }
>  
>  if (dir == DMA_DIRECTION_TO_DEVICE) {
> -bytes = qemu_iovec_to_buf(, 0, ptr, len);
> +bytes = qemu_iovec_to_buf(>iov, 0, ptr, len);
>  } else {
> -bytes = qemu_iovec_from_buf(, 0, ptr, len);
> +bytes = qemu_iovec_from_buf(>iov, 0, ptr, len);
>  }
>  
>  if (unlikely(bytes != len)) {
> @@ -338,8 +334,6 @@ static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, 
> uint32_t len,
>  status = NVME_INVALID_FIELD | NVME_DNR;
>  }
>  
> -qemu_iovec_destroy();
> -
>  return status;
>  }
>  


Reviewed-by: Maxim Levitsky 

Best regards,
Maxim Levitsky

[PATCH v5 18/26] nvme: use preallocated qsg/iov in nvme_dma_prp

[Klaus Jensen]

Since clean up of the request qsg/iov has been moved to the common
nvme_enqueue_req_completion function, there is no need to use a
stack allocated qsg/iov in nvme_dma_prp.

Signed-off-by: Klaus Jensen 
---
 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 e97da35c4ca1..f8c81b9e2202 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -298,23 +298,21 @@ unmap:
 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;
 size_t bytes;
 
-status = nvme_map_prp(n, , , prp1, prp2, len, req);
+status = nvme_map_prp(n, >qsg, >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, );
+residual = dma_buf_write(ptr, len, >qsg);
 } else {
-residual = dma_buf_read(ptr, len, );
+residual = dma_buf_read(ptr, len, >qsg);
 }
 
 if (unlikely(residual)) {
@@ -322,15 +320,13 @@ static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, 
uint32_t len,
 status = NVME_INVALID_FIELD | NVME_DNR;
 }
 
-qemu_sglist_destroy();
-
 return status;
 }
 
 if (dir == DMA_DIRECTION_TO_DEVICE) {
-bytes = qemu_iovec_to_buf(, 0, ptr, len);
+bytes = qemu_iovec_to_buf(>iov, 0, ptr, len);
 } else {
-bytes = qemu_iovec_from_buf(, 0, ptr, len);
+bytes = qemu_iovec_from_buf(>iov, 0, ptr, len);
 }
 
 if (unlikely(bytes != len)) {
@@ -338,8 +334,6 @@ static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, 
uint32_t len,
 status = NVME_INVALID_FIELD | NVME_DNR;
 }
 
-qemu_iovec_destroy();
-
 return status;
 }
 
-- 
2.25.0