* [PATCH] net: tulip: remove redundant assignment to variable new_csr6
@ 2022-01-23 18:34 Colin Ian King
2022-01-24 18:30 ` Jakub Kicinski
0 siblings, 1 reply; 4+ messages in thread
From: Colin Ian King @ 2022-01-23 18:34 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, netdev, linux-parisc
Cc: kernel-janitors, linux-kernel
Variable new_csr6 is being initialized with a value that is never
read, it is being re-assigned later on. The assignment is redundant
and can be removed.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
---
drivers/net/ethernet/dec/tulip/pnic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/dec/tulip/pnic.c b/drivers/net/ethernet/dec/tulip/pnic.c
index 3fb39e32e1b4..653bde48ef44 100644
--- a/drivers/net/ethernet/dec/tulip/pnic.c
+++ b/drivers/net/ethernet/dec/tulip/pnic.c
@@ -21,7 +21,7 @@ void pnic_do_nway(struct net_device *dev)
struct tulip_private *tp = netdev_priv(dev);
void __iomem *ioaddr = tp->base_addr;
u32 phy_reg = ioread32(ioaddr + 0xB8);
- u32 new_csr6 = tp->csr6 & ~0x40C40200;
+ u32 new_csr6;
if (phy_reg & 0x78000000) { /* Ignore baseT4 */
if (phy_reg & 0x20000000) dev->if_port = 5;
--
2.33.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] net: tulip: remove redundant assignment to variable new_csr6
2022-01-23 18:34 [PATCH] net: tulip: remove redundant assignment to variable new_csr6 Colin Ian King
@ 2022-01-24 18:30 ` Jakub Kicinski
2022-01-25 14:14 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Jakub Kicinski @ 2022-01-24 18:30 UTC (permalink / raw)
To: Colin Ian King
Cc: David S . Miller, netdev, linux-parisc, kernel-janitors, linux-kernel
On Sun, 23 Jan 2022 18:34:40 +0000 Colin Ian King wrote:
> Variable new_csr6 is being initialized with a value that is never
> read, it is being re-assigned later on. The assignment is redundant
> and can be removed.
> @@ -21,7 +21,7 @@ void pnic_do_nway(struct net_device *dev)
> struct tulip_private *tp = netdev_priv(dev);
> void __iomem *ioaddr = tp->base_addr;
> u32 phy_reg = ioread32(ioaddr + 0xB8);
> - u32 new_csr6 = tp->csr6 & ~0x40C40200;
> + u32 new_csr6;
>
> if (phy_reg & 0x78000000) { /* Ignore baseT4 */
> if (phy_reg & 0x20000000) dev->if_port = 5;
I can't say I see what you mean, it's not set in some cases:
if (tp->medialock) {
} else if (tp->nwayset && (dev->if_port & 1)) {
next_tick = 1*HZ;
} else if (dev->if_port == 0) {
dev->if_port = 3;
iowrite32(0x33, ioaddr + CSR12);
new_csr6 = 0x01860000;
iowrite32(0x1F868, ioaddr + 0xB8);
} else {
dev->if_port = 0;
iowrite32(0x32, ioaddr + CSR12);
new_csr6 = 0x00420000;
iowrite32(0x1F078, ioaddr + 0xB8);
}
if (tp->csr6 != new_csr6) {
tp->csr6 = new_csr6;
That said clang doesn't complain so maybe I'm missing something static
analysis had figured out about this code.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] net: tulip: remove redundant assignment to variable new_csr6
2022-01-24 18:30 ` Jakub Kicinski
@ 2022-01-25 14:14 ` Dan Carpenter
2022-01-25 15:45 ` Jakub Kicinski
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2022-01-25 14:14 UTC (permalink / raw)
To: Jakub Kicinski
Cc: Colin Ian King, David S . Miller, netdev, linux-parisc,
kernel-janitors, linux-kernel
On Mon, Jan 24, 2022 at 10:30:38AM -0800, Jakub Kicinski wrote:
> On Sun, 23 Jan 2022 18:34:40 +0000 Colin Ian King wrote:
> > Variable new_csr6 is being initialized with a value that is never
> > read, it is being re-assigned later on. The assignment is redundant
> > and can be removed.
>
> > @@ -21,7 +21,7 @@ void pnic_do_nway(struct net_device *dev)
> > struct tulip_private *tp = netdev_priv(dev);
> > void __iomem *ioaddr = tp->base_addr;
> > u32 phy_reg = ioread32(ioaddr + 0xB8);
> > - u32 new_csr6 = tp->csr6 & ~0x40C40200;
> > + u32 new_csr6;
> >
> > if (phy_reg & 0x78000000) { /* Ignore baseT4 */
> > if (phy_reg & 0x20000000) dev->if_port = 5;
>
> I can't say I see what you mean, it's not set in some cases:
>
> if (tp->medialock) {
> } else if (tp->nwayset && (dev->if_port & 1)) {
> next_tick = 1*HZ;
> } else if (dev->if_port == 0) {
> dev->if_port = 3;
> iowrite32(0x33, ioaddr + CSR12);
> new_csr6 = 0x01860000;
> iowrite32(0x1F868, ioaddr + 0xB8);
> } else {
> dev->if_port = 0;
> iowrite32(0x32, ioaddr + CSR12);
> new_csr6 = 0x00420000;
> iowrite32(0x1F078, ioaddr + 0xB8);
> }
> if (tp->csr6 != new_csr6) {
> tp->csr6 = new_csr6;
>
>
> That said clang doesn't complain so maybe I'm missing something static
> analysis had figured out about this code.
You're looking at the wrong function. This is pnic_do_nway() and you're
looking at pnic_timer().
Of course, Colin's patch assumes the current behavior is correct... I
guess the current behavior can't be that terrible since it predates git
and no one has complained.
drivers/net/ethernet/dec/tulip/pnic.c
19 void pnic_do_nway(struct net_device *dev)
20 {
21 struct tulip_private *tp = netdev_priv(dev);
22 void __iomem *ioaddr = tp->base_addr;
23 u32 phy_reg = ioread32(ioaddr + 0xB8);
24 u32 new_csr6 = tp->csr6 & ~0x40C40200;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
25
26 if (phy_reg & 0x78000000) { /* Ignore baseT4 */
27 if (phy_reg & 0x20000000) dev->if_port = 5;
28 else if (phy_reg & 0x40000000) dev->if_port = 3;
29 else if (phy_reg & 0x10000000) dev->if_port = 4;
30 else if (phy_reg & 0x08000000) dev->if_port = 0;
31 tp->nwayset = 1;
32 new_csr6 = (dev->if_port & 1) ? 0x01860000 : 0x00420000;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
33 iowrite32(0x32 | (dev->if_port & 1), ioaddr + CSR12);
34 if (dev->if_port & 1)
35 iowrite32(0x1F868, ioaddr + 0xB8);
36 if (phy_reg & 0x30000000) {
37 tp->full_duplex = 1;
38 new_csr6 |= 0x00000200;
39 }
40 if (tulip_debug > 1)
41 netdev_dbg(dev, "PNIC autonegotiated status %08x, %s\n",
42 phy_reg, medianame[dev->if_port]);
43 if (tp->csr6 != new_csr6) {
44 tp->csr6 = new_csr6;
45 /* Restart Tx */
46 tulip_restart_rxtx(tp);
47 netif_trans_update(dev);
48 }
49 }
50 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] net: tulip: remove redundant assignment to variable new_csr6
2022-01-25 14:14 ` Dan Carpenter
@ 2022-01-25 15:45 ` Jakub Kicinski
0 siblings, 0 replies; 4+ messages in thread
From: Jakub Kicinski @ 2022-01-25 15:45 UTC (permalink / raw)
To: Dan Carpenter
Cc: Colin Ian King, David S . Miller, netdev, linux-parisc,
kernel-janitors, linux-kernel
On Tue, 25 Jan 2022 17:14:01 +0300 Dan Carpenter wrote:
> You're looking at the wrong function. This is pnic_do_nway() and you're
> looking at pnic_timer().
Ah, that explains it! Thanks, applied now.
> Of course, Colin's patch assumes the current behavior is correct... I
> guess the current behavior can't be that terrible since it predates git
> and no one has complained.
Entirely possible this driver was never used in the git era.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-01-25 15:49 UTC | newest]
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2022-01-23 18:34 [PATCH] net: tulip: remove redundant assignment to variable new_csr6 Colin Ian King
2022-01-24 18:30 ` Jakub Kicinski
2022-01-25 14:14 ` Dan Carpenter
2022-01-25 15:45 ` Jakub Kicinski
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