Commit 45d9b378 authored Apr 30, 2017 by Jakub Kicinski Committed by David S. Miller May 01, 2017

netlink: add NULL-friendly helper for setting extended ACK message



As we propagate extended ack reporting throughout various paths in
the kernel it may be that the same function is called with the
extended ack parameter passed as NULL.  One place where that happens
is in drivers which have a centralized reconfiguration function
called both from ndos and from ethtool_ops.  Add a new helper for
setting the error message in such conditions.

Existing helper is left as is to encourage propagating the ext act
fully wherever possible.  It also makes it clear in the code which
messages may be lost due to ext ack being NULL.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 73333626

include/linux/netlink.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -92,6 +92,14 @@ struct netlink_ext_ack {
		(extack)->_msg = _msg; \
		} while (0)

		#define NL_MOD_TRY_SET_ERR_MSG(extack, msg) do { \
		static const char _msg[] = KBUILD_MODNAME ": " msg; \
		struct netlink_ext_ack *_extack = (extack); \
		\
		if (_extack) \
		_extack->_msg = _msg; \
		} while (0)

		extern void netlink_kernel_release(struct sock *sk);
		extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
		extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);

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