Date: Fri, 11 Dec 2020 14:11:42 +0000 (UTC) From: Kristof Provost <kp@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r368552 - stable/12/sys/net Message-ID: <202012111411.0BBEBgD2095225@repo.freebsd.org>
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Author: kp Date: Fri Dec 11 14:11:41 2020 New Revision: 368552 URL: https://svnweb.freebsd.org/changeset/base/368552 Log: MFC r368015: if: Remove ifnet_rwlock It no longer serves any purpose, as evidenced by the fact that we never take it without ifnet_sxlock. This differs slightly from r368015 in that we keep the ifnet_rwlock instance (but no longer take the lock) in case there are external users who still take the lock. Sponsored by: Modirum MDPay Modified: stable/12/sys/net/if.c stable/12/sys/net/if_var.h Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/net/if.c ============================================================================== --- stable/12/sys/net/if.c Fri Dec 11 13:23:59 2020 (r368551) +++ stable/12/sys/net/if.c Fri Dec 11 14:11:41 2020 (r368552) @@ -305,12 +305,8 @@ VNET_DEFINE(struct ifnet **, ifindex_table); /* * The global network interface list (V_ifnet) and related state (such as - * if_index, if_indexlim, and ifindex_table) are protected by an sxlock and - * an rwlock. Either may be acquired shared to stablize the list, but both - * must be acquired writable to modify the list. This model allows us to - * both stablize the interface list during interrupt thread processing, but - * also to stablize it over long-running ioctls, without introducing priority - * inversions and deadlocks. + * if_index, if_indexlim, and ifindex_table) are protected by an sxlock. + * This may be acquired to stabilise the list, or we may rely on NET_EPOCH. */ struct rwlock ifnet_rwlock; RW_SYSINIT_FLAGS(ifnet_rw, &ifnet_rwlock, "ifnet_rw", RW_RECURSE); Modified: stable/12/sys/net/if_var.h ============================================================================== --- stable/12/sys/net/if_var.h Fri Dec 11 13:23:59 2020 (r368551) +++ stable/12/sys/net/if_var.h Fri Dec 11 14:11:41 2020 (r368552) @@ -569,27 +569,11 @@ struct ifmultiaddr { extern struct rwlock ifnet_rwlock; extern struct sx ifnet_sxlock; -#define IFNET_WLOCK() do { \ - sx_xlock(&ifnet_sxlock); \ - rw_wlock(&ifnet_rwlock); \ -} while (0) - -#define IFNET_WUNLOCK() do { \ - rw_wunlock(&ifnet_rwlock); \ - sx_xunlock(&ifnet_sxlock); \ -} while (0) - -/* - * To assert the ifnet lock, you must know not only whether it's for read or - * write, but also whether it was acquired with sleep support or not. - */ -#define IFNET_RLOCK_ASSERT() sx_assert(&ifnet_sxlock, SA_SLOCKED) +#define IFNET_WLOCK() sx_xlock(&ifnet_sxlock) +#define IFNET_WUNLOCK() sx_xunlock(&ifnet_sxlock) +#define IFNET_RLOCK_ASSERT() sx_assert(&ifnet_sxlock, SA_SLOCKED) #define IFNET_RLOCK_NOSLEEP_ASSERT() MPASS(in_epoch(net_epoch_preempt)) -#define IFNET_WLOCK_ASSERT() do { \ - sx_assert(&ifnet_sxlock, SA_XLOCKED); \ - rw_assert(&ifnet_rwlock, RA_WLOCKED); \ -} while (0) - +#define IFNET_WLOCK_ASSERT() sx_assert(&ifnet_sxlock, SA_XLOCKED) #define IFNET_RLOCK() sx_slock(&ifnet_sxlock) #define IFNET_RLOCK_NOSLEEP() struct epoch_tracker ifnet_rlock_et; epoch_enter_preempt(net_epoch_preempt, &ifnet_rlock_et) #define IFNET_RUNLOCK() sx_sunlock(&ifnet_sxlock)
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