2015-02-02 12:04:01

by Selvin Xavier

[permalink] [raw]
Subject: RE: [PATCH 2/2] infiniband: Use unsigned for bit index

Acked-by: Selvin Xavier <[email protected]>

Thanks!

> -----Original Message-----
> From: [email protected] [mailto:linux-rdma-
> [email protected]] On Behalf Of Rasmus Villemoes
> Sent: Friday, January 16, 2015 8:10 PM
> To: Roland Dreier; Sean Hefty; Hal Rosenstock
> Cc: Rasmus Villemoes; [email protected]; linux-
> [email protected]
> Subject: [PATCH 2/2] infiniband: Use unsigned for bit index
>
> In the expressions idx/32 and idx%32, both idx and 32 have signed type, and
> unfortunately the C standard prescribes rounding to 0, so unless gcc can
> prove that idx is non-negative, these cannot be implemented as simple shift
> respectively mask operations. Help gcc by changing the type of idx to
> unsigned - this cuts another few instructions from the generated code.
>
> Signed-off-by: Rasmus Villemoes <[email protected]>
> ---
> drivers/infiniband/hw/ocrdma/ocrdma_verbs.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
> b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
> index eff11e6c6183..61c3047f5170 100644
> --- a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
> +++ b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
> @@ -1479,10 +1479,10 @@ mbx_err:
> return status;
> }
>
> -static void ocrdma_srq_toggle_bit(struct ocrdma_srq *srq, int idx)
> +static void ocrdma_srq_toggle_bit(struct ocrdma_srq *srq, unsigned int
> +idx)
> {
> - int i = idx / 32;
> - unsigned int mask = (1 << (idx % 32));
> + unsigned int i = idx / 32;
> + u32 mask = (1U << (idx % 32));
>
> srq->idx_bit_fields[i] ^= mask;
> }
> --
> 2.1.3
>
> --
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