2022-03-03 09:55:18

by Jiapeng Chong

Subject: [PATCH] net: ethernet: sun: Remove redundant code

Because CAS_FLAG_REG_PLUS is assigned a value of 1, it never enters
these for loops.

Clean up the following smatch warning:

drivers/net/ethernet/sun/cassini.c:3513 cas_start_dma() warn: we never
enter this loop.

drivers/net/ethernet/sun/cassini.c:1239 cas_init_rx_dma() warn: we never
enter this loop.

drivers/net/ethernet/sun/cassini.c:1247 cas_init_rx_dma() warn: we never
enter this loop.

Reported-by: Abaci Robot <[email protected]>
Signed-off-by: Jiapeng Chong <[email protected]>
---
drivers/net/ethernet/sun/cassini.c | 16 ----------------
1 file changed, 16 deletions(-)

diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
index 947a76a788c7..153edc5eadad 100644
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -1235,19 +1235,6 @@ static void cas_init_rx_dma(struct cas *cp)
*/
readl(cp->regs + REG_INTR_STATUS_ALIAS);
writel(INTR_RX_DONE | INTR_RX_BUF_UNAVAIL, cp->regs + REG_ALIAS_CLEAR);
- if (cp->cas_flags & CAS_FLAG_REG_PLUS) {
- for (i = 1; i < N_RX_COMP_RINGS; i++)
- readl(cp->regs + REG_PLUS_INTRN_STATUS_ALIAS(i));
-
- /* 2 is different from 3 and 4 */
- if (N_RX_COMP_RINGS > 1)
- writel(INTR_RX_DONE_ALT | INTR_RX_BUF_UNAVAIL_1,
- cp->regs + REG_PLUS_ALIASN_CLEAR(1));
-
- for (i = 2; i < N_RX_COMP_RINGS; i++)
- writel(INTR_RX_DONE_ALT,
- cp->regs + REG_PLUS_ALIASN_CLEAR(i));
- }

/* set up pause thresholds */
val = CAS_BASE(RX_PAUSE_THRESH_OFF,
@@ -3509,9 +3496,6 @@ static inline void cas_start_dma(struct cas *cp)
if (N_RX_DESC_RINGS > 1)
writel(RX_DESC_RINGN_SIZE(1) - 4,
cp->regs + REG_PLUS_RX_KICK1);
-
- for (i = 1; i < N_RX_COMP_RINGS; i++)
- writel(0, cp->regs + REG_PLUS_RX_COMPN_TAIL(i));
}
}

--
2.20.1.7.g153144c

2022-03-03 17:32:00

by Andrew Lunn

Subject: Re: [PATCH] net: ethernet: sun: Remove redundant code

On Thu, Mar 03, 2022 at 05:14:40PM +0800, Jiapeng Chong wrote:
> Because CAS_FLAG_REG_PLUS is assigned a value of 1, it never enters
> these for loops.

Please can you expand this comment, it is not clear to my what you
mean here. When i look at:

/* check pci invariants */
static void cas_check_pci_invariants(struct cas *cp)
{
struct pci_dev *pdev = cp->pdev;

cp->cas_flags = 0;
if ((pdev->vendor == PCI_VENDOR_ID_SUN) &&
(pdev->device == PCI_DEVICE_ID_SUN_CASSINI)) {
if (pdev->revision >= CAS_ID_REVPLUS)
cp->cas_flags |= CAS_FLAG_REG_PLUS;

it is not obvious why it could not enter these loops.

Andrew

>
> Clean up the following smatch warning:
>
> drivers/net/ethernet/sun/cassini.c:3513 cas_start_dma() warn: we never
> enter this loop.
>
> drivers/net/ethernet/sun/cassini.c:1239 cas_init_rx_dma() warn: we never
> enter this loop.
>
> drivers/net/ethernet/sun/cassini.c:1247 cas_init_rx_dma() warn: we never
> enter this loop.
>
> Reported-by: Abaci Robot <[email protected]>
> Signed-off-by: Jiapeng Chong <[email protected]>
> ---
> drivers/net/ethernet/sun/cassini.c | 16 ----------------
> 1 file changed, 16 deletions(-)
>
> diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
> index 947a76a788c7..153edc5eadad 100644
> --- a/drivers/net/ethernet/sun/cassini.c
> +++ b/drivers/net/ethernet/sun/cassini.c
> @@ -1235,19 +1235,6 @@ static void cas_init_rx_dma(struct cas *cp)
> */
> readl(cp->regs + REG_INTR_STATUS_ALIAS);
> writel(INTR_RX_DONE | INTR_RX_BUF_UNAVAIL, cp->regs + REG_ALIAS_CLEAR);
> - if (cp->cas_flags & CAS_FLAG_REG_PLUS) {
> - for (i = 1; i < N_RX_COMP_RINGS; i++)
> - readl(cp->regs + REG_PLUS_INTRN_STATUS_ALIAS(i));
> -
> - /* 2 is different from 3 and 4 */
> - if (N_RX_COMP_RINGS > 1)
> - writel(INTR_RX_DONE_ALT | INTR_RX_BUF_UNAVAIL_1,
> - cp->regs + REG_PLUS_ALIASN_CLEAR(1));
> -
> - for (i = 2; i < N_RX_COMP_RINGS; i++)
> - writel(INTR_RX_DONE_ALT,
> - cp->regs + REG_PLUS_ALIASN_CLEAR(i));
> - }
>
> /* set up pause thresholds */
> val = CAS_BASE(RX_PAUSE_THRESH_OFF,
> @@ -3509,9 +3496,6 @@ static inline void cas_start_dma(struct cas *cp)
> if (N_RX_DESC_RINGS > 1)
> writel(RX_DESC_RINGN_SIZE(1) - 4,
> cp->regs + REG_PLUS_RX_KICK1);
> -
> - for (i = 1; i < N_RX_COMP_RINGS; i++)
> - writel(0, cp->regs + REG_PLUS_RX_COMPN_TAIL(i));
> }
> }
>
> --
> 2.20.1.7.g153144c
>