rseq: Optimize rseq_update_cpu_id()

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Two put_user() in rseq_update_cpu_id() are replaced
by a pair of unsafe_put_user() with appropriate surroundings.

This removes one stac/clac pair on x86 in fast path.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lkml.kernel.org/r/20210413203352.71350-2-eric.dumazet@gmail.com

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Eric Dumazet 2021-04-13 13:33:50 -07:00 • committed by Peter Zijlstra

parent 4bad58ebc8

commit 60af388d23

1 changed files with 11 additions and 4 deletions

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kernel/rseq.c

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