lib/plist.c: enforce memory ordering in plist_check_list
There exists an iteration over a plist in plist_check_list(), and memory dependency exists between variables "prev", "next" and "prev->next". As plist is used in the scheduling subsystem, we should guarantee the memory ordering between multiple processors. Using macro "WRITE_ONCE()" can help us to ensure the memory ordering as it was stated in "Documentation/memory-barriers.txt". Link: https://lkml.kernel.org/r/20240526140139.17220-1-richard120310@gmail.com Signed-off-by: I Hsin Cheng <richard120310@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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@ -47,8 +47,8 @@ static void plist_check_list(struct list_head *top)
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plist_check_prev_next(top, prev, next);
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plist_check_prev_next(top, prev, next);
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while (next != top) {
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while (next != top) {
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prev = next;
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WRITE_ONCE(prev, next);
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next = prev->next;
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WRITE_ONCE(next, prev->next);
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plist_check_prev_next(top, prev, next);
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plist_check_prev_next(top, prev, next);
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}
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}
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}
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}
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