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authorHerbert Xu <herbert@gondor.apana.org.au>2007-10-23 11:26:25 +0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-23 09:01:31 -0700
commita98ce5c6feead6bfedefabd46cb3d7f5be148d9a (patch)
tree7bbd027e40805966ad908e40f09ffd412a72a88b /net/sctp/sysctl.c
parent48d2268473a66fe3aa78fb13b09ee59d6ee95073 (diff)
Fix synchronize_irq races with IRQ handler
As it is some callers of synchronize_irq rely on memory barriers to provide synchronisation against the IRQ handlers. For example, the tg3 driver does tp->irq_sync = 1; smp_mb(); synchronize_irq(); and then in the IRQ handler: if (!tp->irq_sync) netif_rx_schedule(dev, &tp->napi); Unfortunately memory barriers only work well when they come in pairs. Because we don't actually have memory barriers on the IRQ path, the memory barrier before the synchronize_irq() doesn't actually protect us. In particular, synchronize_irq() may return followed by the result of netif_rx_schedule being made visible. This patch (mostly written by Linus) fixes this by using spin locks instead of memory barries on the synchronize_irq() path. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net/sctp/sysctl.c')
0 files changed, 0 insertions, 0 deletions