Re: [Qemu-devel] [PATCHv2] Reducing stack frame size in stream_process_mem2s()

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Tue, Oct 04, 2016 at 11:41:42PM +0530, rutu.shah.26@gmail.com wrote:
> From: Rutuja Shah <rutu.shah.26@gmail.com>
> 
> Hi,
> This patch allocates memory for txbuf in struct Stream rather than the stack.
> As a result, the stack frame size is reduced of stream_process_mem2s().

Hi Rutuja,

A nit-pick:
The commit message is not meant to be a converstation-like message, so
normally we don't include greetings.
The expected format is to have an empty line between the message and
the SoB line.

Here's an example:

Allocate memory for txbuf in struct Stream rather than on the stack.
As a result, the stack frame size is reduced for stream_process_mem2s().

Signed-off-by: Rutuja Shah <rutu.shah.26@gmail.com>


Other than that, this looks good to me:
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>


> Signed-off-by: Rutuja Shah <rutu.shah.26@gmail.com>
> ---
>  hw/dma/xilinx_axidma.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
> index b135a5f..6065689 100644
> --- a/hw/dma/xilinx_axidma.c
> +++ b/hw/dma/xilinx_axidma.c
> @@ -111,6 +111,7 @@ struct Stream {
>      unsigned int complete_cnt;
>      uint32_t regs[R_MAX];
>      uint8_t app[20];
> +    unsigned char txbuf[16 * 1024];
>  };
>  
>  struct XilinxAXIDMAStreamSlave {
> @@ -256,7 +257,6 @@ static void stream_process_mem2s(struct Stream *s, StreamSlave *tx_data_dev,
>                                   StreamSlave *tx_control_dev)
>  {
>      uint32_t prev_d;
> -    unsigned char txbuf[16 * 1024];
>      unsigned int txlen;
>  
>      if (!stream_running(s) || stream_idle(s)) {
> @@ -277,17 +277,17 @@ static void stream_process_mem2s(struct Stream *s, StreamSlave *tx_data_dev,
>          }
>  
>          txlen = s->desc.control & SDESC_CTRL_LEN_MASK;
> -        if ((txlen + s->pos) > sizeof txbuf) {
> +        if ((txlen + s->pos) > sizeof s->txbuf) {
>              hw_error("%s: too small internal txbuf! %d\n", __func__,
>                       txlen + s->pos);
>          }
>  
>          cpu_physical_memory_read(s->desc.buffer_address,
> -                                 txbuf + s->pos, txlen);
> +                                 s->txbuf + s->pos, txlen);
>          s->pos += txlen;
>  
>          if (stream_desc_eof(&s->desc)) {
> -            stream_push(tx_data_dev, txbuf, s->pos);
> +            stream_push(tx_data_dev, s->txbuf, s->pos);
>              s->pos = 0;
>              stream_complete(s);
>          }
> -- 
> 1.9.1
>