On Fri, 2012-02-24 at 22:27 +0530, santosh nayak wrote:
> From: Santosh Nayak <santoshprasadnayak@xxxxxxxxx>
>
> Sparse is giving the following warning:
> "warning: dubious: x | !y"
>
> "enic_are_pp_different" is static and expected to return true or false.
> Logical or is indended here. With logical or, in best case, execution will be
> faster because if leftmost operand is true then no need to check other operands.
The shortcut behaviour of logical-or means more conditional jumps to be
predicted and more potential for pipeline stalls. So bitwise-or can in
some cases be more efficient. But this function appears to be
control-path code where micro-optimisation just doesn't matter. Use of
logical-or can be justified purely on the grounds of clarity.
Ben.
> Signed-off-by: Santosh Nayak <santoshprasadnayak@xxxxxxxxx>
> ---
> drivers/net/ethernet/cisco/enic/enic_pp.c | 8 ++++----
> 1 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/cisco/enic/enic_pp.c b/drivers/net/ethernet/cisco/enic/enic_pp.c
> index dafea1e..3a6de22 100644
> --- a/drivers/net/ethernet/cisco/enic/enic_pp.c
> +++ b/drivers/net/ethernet/cisco/enic/enic_pp.c
> @@ -159,10 +159,10 @@ static int enic_unset_port_profile(struct enic *enic, int vf)
> static int enic_are_pp_different(struct enic_port_profile *pp1,
> struct enic_port_profile *pp2)
> {
> - return strcmp(pp1->name, pp2->name) | !!memcmp(pp1->instance_uuid,
> - pp2->instance_uuid, PORT_UUID_MAX) |
> - !!memcmp(pp1->host_uuid, pp2->host_uuid, PORT_UUID_MAX) |
> - !!memcmp(pp1->mac_addr, pp2->mac_addr, ETH_ALEN);
> + return strcmp(pp1->name, pp2->name) || !!memcmp(pp1->instance_uuid,
> + pp2->instance_uuid, PORT_UUID_MAX) ||
> + !!memcmp(pp1->host_uuid, pp2->host_uuid, PORT_UUID_MAX) ||
> + !!memcmp(pp1->mac_addr, pp2->mac_addr, ETH_ALEN);
> }
>
> static int enic_pp_preassociate(struct enic *enic, int vf,
--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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