| Message ID | 1637204701-8224-1-git-send-email-yang.lee@linux.alibaba.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [-next] net: mvpp2: Use div64_ul instead of do_div | expand |
On 11/17/21 7:05 PM, Yang Li wrote: > do_div() does a 64-by-32 division. Here the divisor is an > unsigned long which on some platforms is 64 bit wide. So use > div64_ul instead of do_div to avoid a possible truncation. > > Eliminate the following coccicheck warning: > ./drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:2742:1-7: WARNING: > do_div() does a 64-by-32 division, please consider using div64_ul > instead. > > Reported-by: Abaci Robot <abaci@linux.alibaba.com> > Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> > --- > drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > index df6c793..41244a5 100644 > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c > @@ -2739,7 +2739,7 @@ static u32 mvpp2_cycles_to_usec(u32 cycles, unsigned long clk_hz) > { > u64 tmp = (u64)cycles * USEC_PER_SEC; > > - do_div(tmp, clk_hz); > + tmp = div64_ul(tmp, clk_hz); > > return tmp > U32_MAX ? U32_MAX : tmp; > } > This is silly, clk_hz fits in a u32, why pretends it is 64bit ? diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c index df6c793f4b1b04eb1f812ce2a3a82a39cde0f68b..1bea316bf13ac42ad65ba326fc1d9e206546766e 100644 --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c @@ -2726,7 +2726,7 @@ static void mvpp2_tx_pkts_coal_set(struct mvpp2_port *port, } } -static u32 mvpp2_usec_to_cycles(u32 usec, unsigned long clk_hz) +static u32 mvpp2_usec_to_cycles(u32 usec, u32 clk_hz) { u64 tmp = (u64)clk_hz * usec; @@ -2735,7 +2735,7 @@ static u32 mvpp2_usec_to_cycles(u32 usec, unsigned long clk_hz) return tmp > U32_MAX ? U32_MAX : tmp; } -static u32 mvpp2_cycles_to_usec(u32 cycles, unsigned long clk_hz) +static u32 mvpp2_cycles_to_usec(u32 cycles, u32 clk_hz) { u64 tmp = (u64)cycles * USEC_PER_SEC; @@ -2748,7 +2748,7 @@ static u32 mvpp2_cycles_to_usec(u32 cycles, unsigned long clk_hz) static void mvpp2_rx_time_coal_set(struct mvpp2_port *port, struct mvpp2_rx_queue *rxq) { - unsigned long freq = port->priv->tclk; + u32 freq = port->priv->tclk; u32 val = mvpp2_usec_to_cycles(rxq->time_coal, freq); if (val > MVPP2_MAX_ISR_RX_THRESHOLD) { @@ -2764,7 +2764,7 @@ static void mvpp2_rx_time_coal_set(struct mvpp2_port *port, static void mvpp2_tx_time_coal_set(struct mvpp2_port *port) { - unsigned long freq = port->priv->tclk; + u32 freq = port->priv->tclk; u32 val = mvpp2_usec_to_cycles(port->tx_time_coal, freq); if (val > MVPP2_MAX_ISR_TX_THRESHOLD) {
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c index df6c793..41244a5 100644 --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c @@ -2739,7 +2739,7 @@ static u32 mvpp2_cycles_to_usec(u32 cycles, unsigned long clk_hz) { u64 tmp = (u64)cycles * USEC_PER_SEC; - do_div(tmp, clk_hz); + tmp = div64_ul(tmp, clk_hz); return tmp > U32_MAX ? U32_MAX : tmp; }
do_div() does a 64-by-32 division. Here the divisor is an unsigned long which on some platforms is 64 bit wide. So use div64_ul instead of do_div to avoid a possible truncation. Eliminate the following coccicheck warning: ./drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:2742:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_ul instead. Reported-by: Abaci Robot <abaci@linux.alibaba.com> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> --- drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)