net: fix sk_memory_allocated_{add|sub} vs softirqs
Jonathan Heathcote reported a regression caused by blamed commit on aarch64 architecture. x86 happens to have irq-safe __this_cpu_add_return() and __this_cpu_sub(), but this is not generic. I think my confusion came from "struct sock" argument, because these helpers are called with a locked socket. But the memory accounting is per-proto (and per-cpu after the blamed commit). We might cleanup these helpers later to directly accept a "struct proto *proto" argument. Switch to this_cpu_add_return() and this_cpu_xchg() operations, and get rid of preempt_disable()/preempt_enable() pairs. Fast path becomes a bit faster as a result :) Many thanks to Jonathan Heathcote for his awesome report and investigations. Fixes: 3cd3399d ("net: implement per-cpu reserves for memory_allocated") Reported-by:Jonathan Heathcote <jonathan.heathcote@bbc.co.uk> Closes: https://lore.kernel.org/netdev/VI1PR01MB42407D7947B2EA448F1E04EFD10D2@VI1PR01MB4240.eurprd01.prod.exchangelabs.com/ Signed-off-by:
Eric Dumazet <edumazet@google.com> Acked-by:
Soheil Hassas Yeganeh <soheil@google.com> Reviewed-by:
Shakeel Butt <shakeel.butt@linux.dev> Link: https://lore.kernel.org/r/20240421175248.1692552-1-edumazet@google.com Signed-off-by:
Jakub Kicinski <kuba@kernel.org>
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