Re: [PATCH 2/2] hw: megasas: consider 'iov_count=0' is an error in megasas_map_sgl

[Li Qiang]

Oh, sorry to forget to CC Alexander Bulekov.

Thanks,
Li Qiang

Li Qiang <liq3ea@163.com> 于2020年8月15日周六 下午10:20写道：
>
> Currently in 'megasas_map_sgl' when 'iov_count=0' will just return
> success however the 'cmd' doens't contain any iov. This will cause
> the assert in 'scsi_dma_complete' failed. This is because in
> 'dma_blk_cb' the 'dbs->sg_cur_index == dbs->sg->nsg' will be true
> and just call 'dma_complete'. However now there is no aiocb returned.
>
> This fixes the LP#1878263:
>
> -->https://bugs.launchpad.net/qemu/+bug/1878263
>
> Reported-by: Alexander Bulekov <alxndr@bu.edu>
> Signed-off-by: Li Qiang <liq3ea@163.com>
> ---
>  hw/scsi/megasas.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
> index d6c9680c36..9562c58a2d 100644
> --- a/hw/scsi/megasas.c
> +++ b/hw/scsi/megasas.c
> @@ -278,7 +278,7 @@ static int megasas_map_sgl(MegasasState *s, MegasasCmd 
> *cmd, union mfi_sgl *sgl)
>
>      cmd->flags = le16_to_cpu(cmd->frame->header.flags);
>      iov_count = cmd->frame->header.sge_count;
> -    if (iov_count > MEGASAS_MAX_SGE) {
> +    if (!iov_count || iov_count > MEGASAS_MAX_SGE) {
>          trace_megasas_iovec_sgl_overflow(cmd->index, iov_count,
>                                           MEGASAS_MAX_SGE);
>          return -1;
> --
> 2.17.1
>