Date: Tue, 11 Nov 2008 10:16:26 +0100 From: Dan Lukes <dan@obluda.cz> To: yongari@FreeBSD.org Cc: freebsd-bugs@FreeBSD.org Subject: Re: kern/128766: [ PATCH ] VGE's [rt]xcsum can't be switched off Message-ID: <49194D6A.30807@obluda.cz> In-Reply-To: <200811110127.mAB1RiQV095192@freefall.freebsd.org> References: <200811110127.mAB1RiQV095192@freefall.freebsd.org>
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yongari@FreeBSD.org napsal/wrote, On 11/11/08 02:27:
> It seems that the hardware does not require reinitialization when
> checksum offload configuration is changed.
> Would you try patch at the followng URL?
True, vge_init() is not necesarry. Your code ...
===================================================================
if ((mask & IFCAP_TXCSUM) != 0 &&
(ifp->if_capabilities & IFCAP_TXCSUM) != 0) {
ifp->if_capenable ^= IFCAP_TXCSUM;
if ((ifp->if_capenable & IFCAP_TXCSUM) != 0)
ifp->if_hwassist |= VGE_CSUM_FEATURES;
else
ifp->if_hwassist &= ~VGE_CSUM_FEATURES;
}
if ((mask & IFCAP_RXCSUM) != 0 &&
(ifp->if_capabilities & IFCAP_RXCSUM) != 0)
ifp->if_capenable ^= IFCAP_RXCSUM;
}
===================================================================
... will work, but is suboptimal.
The tests (ifp->if_capabilities & IFCAP_TXCSUM) and
(ifp->if_capabilities & IFCAP_RXCSUM) is true everytime because the test
is done already in upper layer (see net.c:ifhwioctl(), it return EINVAL
when someone try to set capabilities not offered by driver)
Code with such tests removed ...
===================================================================
if (mask & IFCAP_TXCSUM) != 0) {
ifp->if_capenable ^= IFCAP_TXCSUM;
if ((ifp->if_capenable & IFCAP_TXCSUM) != 0)
ifp->if_hwassist |= VGE_CSUM_FEATURES;
else
ifp->if_hwassist &= ~VGE_CSUM_FEATURES;
}
if (mask & IFCAP_RXCSUM != 0)
ifp->if_capenable ^= IFCAP_RXCSUM;
}
===================================================================
... is OK but ~VGE_CSUM_FEATURES shall be ~VGE_CSUM_FEATURE instead
(-VGE_CSUM_FEATURES may not be equal to ~VGE_CSUM_FEATURES althought it
is on most platforms).
In advance, we shall catch attempt to modify capabilities that are
supported by driver, but that driver doesn't support to be switched off.
If we shall do
mask ^= IFCAP_POLLING
on the end of IFCAP_POLLING handling and
mask ^= (IFCAP_TXCSUM | IFCAP_RXCSUM)
on the end of CSUM handling then we can do
if (mask != 0)
return(ENOTSUPP)
on the end of SIOCSIFCAP.
The resulting patch is attached.
Dan
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--- /usr/src/sys/dev/vge/if_vgevar.h.orig 2008-11-10 23:53:04.000000000 +0100
+++ /usr/src/sys/dev/vge/if_vgevar.h 2008-11-11 02:19:20.000000000 +0100
@@ -2228,16 +2228,21 @@
VGE_UNLOCK(sc);
}
}
+ mask ^= IFCAP_POLLING;
#endif /* DEVICE_POLLING */
- if (mask & IFCAP_HWCSUM) {
- ifp->if_capenable |= ifr->ifr_reqcap & (IFCAP_HWCSUM);
+ if (mask & IFCAP_TXCSUM) {
+ ifp->if_capenable ^= IFCAP_TXCSUM;
if (ifp->if_capenable & IFCAP_TXCSUM)
- ifp->if_hwassist = VGE_CSUM_FEATURES;
+ ifp->if_hwassist |= VGE_CSUM_FEATURES;
else
- ifp->if_hwassist = 0;
- if (ifp->if_drv_flags & IFF_DRV_RUNNING)
- vge_init(sc);
+ ifp->if_hwassist &= ~VGE_CSUM_FEATURES;
}
+ if (mask & IFCAP_RXCSUM) {
+ ifp->if_capenable ^= IFCAP_RXCSUM;
+ }
+ mask ^= (IFCAP_TXCSUM | IFCAP_RXCSUM);
+ if (mask != 0)
+ return(ENODEV);
}
break;
default:
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