Re: [Qemu-devel] [PATCH] migration: fix warning for source_return_path_thread

[Paolo Bonzini <pbonzini@redhat.com>]

On 09/03/2016 07:12, Peter Xu wrote:
> max_len is not necessary, while it brings a warning during compilation
> when specify "-Wstack-usage=1000000". Replacing using sizeof().
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  migration/migration.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 0129d9f..6680d95 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1268,8 +1268,7 @@ static void *source_return_path_thread(void *opaque)
>      MigrationState *ms = opaque;
>      QEMUFile *rp = ms->rp_state.from_dst_file;
>      uint16_t header_len, header_type;
> -    const int max_len = 512;
> -    uint8_t buf[max_len];
> +    uint8_t buf[512];
>      uint32_t tmp32, sibling_error;
>      ram_addr_t start = 0; /* =0 to silence warning */
>      size_t  len = 0, expected_len;
> @@ -1292,7 +1291,7 @@ static void *source_return_path_thread(void *opaque)
>  
>          if ((rp_cmd_args[header_type].len != -1 &&
>              header_len != rp_cmd_args[header_type].len) ||
> -            header_len > max_len) {
> +            header_len > sizeof(buf)) {

sizeof works fine because buf is an array of bytes, but ARRAY_SIZE is
better because it works for any type of buffer.

Paolo

>              error_report("RP: Received '%s' message (0x%04x) with"
>                      "incorrect length %d expecting %zu",
>                      rp_cmd_args[header_type].name, header_type, header_len,
>