[PATCH] batman-adv: compat: Fix build on RHEL 8.1 and clones

[PATCH] batman-adv: compat: Fix build on RHEL 8.1 and clones

[Felix Kaechele]

RHEL 8.1 backported some fixes from newer kernels so we need to treat it's 4.18
kernel as if it were a newer kernel in some cases.

Signed-off-by: Felix Kaechele <felix@kaechele.ca>
---
 compat-include/linux/igmp.h    | 2 +-
 compat-include/linux/uaccess.h | 2 +-
 compat-include/net/addrconf.h  | 2 +-
 compat.h                       | 6 ++++++
 4 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/compat-include/linux/igmp.h b/compat-include/linux/igmp.h
index ecedc915..60606f05 100644
--- a/compat-include/linux/igmp.h
+++ b/compat-include/linux/igmp.h
@@ -17,7 +17,7 @@
 
 int ip_mc_check_igmp(struct sk_buff *skb);
 
-#elif LINUX_VERSION_CODE < KERNEL_VERSION(5, 1, 0)
+#elif LINUX_VERSION_CODE < KERNEL_VERSION(5, 1, 0) && !defined(RHEL_81)
 
 static inline int batadv_ip_mc_check_igmp(struct sk_buff *skb)
 {
diff --git a/compat-include/linux/uaccess.h b/compat-include/linux/uaccess.h
index e81ed805..5a337441 100644
--- a/compat-include/linux/uaccess.h
+++ b/compat-include/linux/uaccess.h
@@ -13,7 +13,7 @@
 #include <linux/version.h>
 #include_next <linux/uaccess.h>
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 0, 0)
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 0, 0) && !defined(RHEL_81)
 
 static inline int batadv_access_ok(int type, const void __user *p,
 				   unsigned long size)
diff --git a/compat-include/net/addrconf.h b/compat-include/net/addrconf.h
index b826ee95..5ab19043 100644
--- a/compat-include/net/addrconf.h
+++ b/compat-include/net/addrconf.h
@@ -17,7 +17,7 @@
 
 int ipv6_mc_check_mld(struct sk_buff *skb);
 
-#elif LINUX_VERSION_CODE < KERNEL_VERSION(5, 1, 0)
+#elif LINUX_VERSION_CODE < KERNEL_VERSION(5, 1, 0) && !defined(RHEL_81)
 
 static inline int batadv_ipv6_mc_check_mld(struct sk_buff *skb)
 {
diff --git a/compat.h b/compat.h
index 980fca9f..7f4a5ee4 100644
--- a/compat.h
+++ b/compat.h
@@ -44,6 +44,12 @@
 
 #endif /* < KERNEL_VERSION(4, 15, 0) */
 
+#ifdef RHEL_RELEASE_CODE
+# if RHEL_RELEASE_CODE >= RHEL_RELEASE_VERSION(8, 1)
+#  define RHEL_81
+# endif
+#endif /* RHEL_RELEASE_CODE */
+
 #endif /* __KERNEL__ */
 
 #endif /* _NET_BATMAN_ADV_COMPAT_H_ */
-- 
2.24.1

Re: [PATCH] batman-adv: compat: Fix build on RHEL 8.1 and clones

[Sven Eckelmann]

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On Saturday, 25 January 2020 19:07:45 CET Felix Kaechele wrote:
> RHEL 8.1 backported some fixes from newer kernels so we need to treat it's 4.18
> kernel as if it were a newer kernel in some cases.

I am personally not really happy about supporting all kind of weird Linux 
kernel forks.

Anyway, if you really want to maintain the RHEL support (for reasonable 
versions which are based on reasonable new upstream kernels) then I would 
propose to avoid this RHEL_81. Instead it might be better to just add 
RHEL_RELEASE_VERSION + RHEL_RELEASE_CODE [1] to 
compat-include/linux/version.h. And then just use them like the backports.git 
is using them [2].

Kind regards,
	Sven

[1] https://git.kernel.org/pub/scm/linux/kernel/git/backports/backports.git/tree/backport/backport-include/linux/version.h?id=368e8c51a59629ea7d681f5b96d4f5a9f89ad1a6#n140
[2] https://git.kernel.org/pub/scm/linux/kernel/git/backports/backports.git/tree/backport/backport-include/linux/skbuff.h?id=368e8c51a59629ea7d681f5b96d4f5a9f89ad1a6#n140

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Re: [PATCH] batman-adv: compat: Fix build on RHEL 8.1 and clones

[Felix Kaechele]

Hi,

On 2020-01-25 2:17 p.m., Sven Eckelmann wrote:

> I am personally not really happy about supporting all kind of weird Linux
> kernel forks.

No worries. Just saw that there are some provisions for Debian (which I 
guess is what some of the maintainers are using) in the code. But I do 
see that all the Ubuntu specific stuff that backports has isn't in there 
either.

> Anyway, if you really want to maintain the RHEL support (for reasonable
> versions which are based on reasonable new upstream kernels) then I would
> propose to avoid this RHEL_81. Instead it might be better to just add
> RHEL_RELEASE_VERSION + RHEL_RELEASE_CODE [1] to
> compat-include/linux/version.h. And then just use them like the backports.git
> is using them [2].

I'm not interested in maintaining this upstream indefinitely and I agree 
with you that carrying around fixes for all kinds of weird quirks is a 
burden on maintainers.

I'm happy to just carry this patch in my DKMS RPM packages I maintain 
for batman-adv.

Regards,
Felix

Re: [PATCH] batman-adv: compat: Fix build on RHEL 8.1 and clones

[Sven Eckelmann]

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On Tuesday, 28 January 2020 18:19:16 CET Felix Kaechele wrote:
[..]
> No worries. Just saw that there are some provisions for Debian (which I 
> guess is what some of the maintainers are using) in the code.

Good point, there was the make-kpkg hack. @Linus, can this be dropped? The 
correct way to build a private Debian package of the kernel is to use
`make deb-pkg`

[...]
> I'm not interested in maintaining this upstream indefinitely and I agree 
> with you that carrying around fixes for all kinds of weird quirks is a 
> burden on maintainers.
> 
> I'm happy to just carry this patch in my DKMS RPM packages I maintain 
> for batman-adv.

As said, if you want to maintain it upstream then feel free to resent the 
patch with the requested change. The "reasonable new upstream kernels" part 
was about the way we drop support for older kernels. The oldest kernel we want 
to support is the the oldest kernel not marked as EOL on 
https://www.kernel.org/category/releases.html

If the RHEL quirks don't become too bothersome and you take care of it then it 
should be a relative small problem for us. I just don't want to be the person 
taking care of kernels which I don't use.

Kind regards,
	Sven

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