Re: [Qemu-devel] [PATCH 1/3] migration/postcopy: the valid condition is one less then end

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Wei Yang (richardw.yang@linux.intel.com) wrote:
> If one equals end, it means we have gone through the whole bitmap.
> 
> Use a more restrict check to skip a unnecessary condition.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

Yes, I don't think that'll break, since I think the find_next_zero_bit
will also return end, and then discard_length would be 0; still I think
it's a correct fix.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  migration/ram.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 908517fc2b..b78169e811 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2777,7 +2777,7 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms,
>      for (current = 0; current < end; ) {
>          unsigned long one = find_next_bit(unsentmap, end, current);
>  
> -        if (one <= end) {
> +        if (one < end) {
>              unsigned long zero = find_next_zero_bit(unsentmap, end, one + 1);
>              unsigned long discard_length;
>  
> -- 
> 2.19.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK