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authorPeter Zijlstra <peterz@infradead.org>2021-03-08 09:38:12 +0100
committerPeter Zijlstra <peterz@infradead.org>2021-03-10 09:51:45 +0100
commitd5b0e0677bfd5efd17c5bbb00156931f0d41cb85 (patch)
tree5146fe6e9037f751b3629c32771d64c721f748c8 /include/linux/u64_stats_sync.h
parent50bf8080a94d171e843fc013abec19d8ab9f50ae (diff)
u64_stats,lockdep: Fix u64_stats_init() vs lockdep
Jakub reported that: static struct net_device *rtl8139_init_board(struct pci_dev *pdev) { ... u64_stats_init(&tp->rx_stats.syncp); u64_stats_init(&tp->tx_stats.syncp); ... } results in lockdep getting confused between the RX and TX stats lock. This is because u64_stats_init() is an inline calling seqcount_init(), which is a macro using a static variable to generate a lockdep class. By wrapping that in an inline, we negate the effect of the macro and fold the static key variable, hence the confusion. Fix by also making u64_stats_init() a macro for the case where it matters, leaving the other case an inline for argument validation etc. Reported-by: Jakub Kicinski <kuba@kernel.org> Debugged-by: "Ahmed S. Darwish" <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: "Erhard F." <erhard_f@mailbox.org> Link: https://lkml.kernel.org/r/YEXicy6+9MksdLZh@hirez.programming.kicks-ass.net
Diffstat (limited to 'include/linux/u64_stats_sync.h')
-rw-r--r--include/linux/u64_stats_sync.h7
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h
index c6abb79501b3..e81856c0ba13 100644
--- a/include/linux/u64_stats_sync.h
+++ b/include/linux/u64_stats_sync.h
@@ -115,12 +115,13 @@ static inline void u64_stats_inc(u64_stats_t *p)
}
#endif
+#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
+#define u64_stats_init(syncp) seqcount_init(&(syncp)->seq)
+#else
static inline void u64_stats_init(struct u64_stats_sync *syncp)
{
-#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
- seqcount_init(&syncp->seq);
-#endif
}
+#endif
static inline void u64_stats_update_begin(struct u64_stats_sync *syncp)
{