| Message ID | 1421419196-4659-2-git-send-email-linux@rasmusvillemoes.dk (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
Acked-by: Selvin Xavier <selvin.xavier@emulex.com> Thanks! > -----Original Message----- > From: linux-rdma-owner@vger.kernel.org [mailto:linux-rdma- > owner@vger.kernel.org] On Behalf Of Rasmus Villemoes > Sent: Friday, January 16, 2015 8:10 PM > To: Roland Dreier; Sean Hefty; Hal Rosenstock > Cc: Rasmus Villemoes; linux-rdma@vger.kernel.org; linux- > kernel@vger.kernel.org > 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 <linux@rasmusvillemoes.dk> > --- > 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the > body of a message to majordomo@vger.kernel.org More majordomo info at > http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; }
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 <linux@rasmusvillemoes.dk> --- drivers/infiniband/hw/ocrdma/ocrdma_verbs.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)