random: fix circular include dependency on arm64 after addition of percpu.h

[Willy Tarreau]

Daniel Díaz and Kees Cook independently reported that commit f227e3ec3b5c
("random32: update the net random state on interrupt and activity") broke
arm64 due to a circular dependency on include files since the addition of
percpu.h in random.h.

The correct fix would definitely be to move all the prandom32 stuff out
of random.h but for backporting, a smaller solution is preferred. This
one replaces linux/percpu.h with asm/percpu.h, and this fixes the problem
on x86_64, arm64, arm, and mips. Note that moving percpu.h around didn't
change anything and that removing it entirely broke differently. When
backporting, such options might still be considered if this patch fails
to help.

Reported-by: Daniel Díaz <daniel.diaz@xxxxxxxxxx>
Reported-by: Kees Cook <keescook@xxxxxxxxxxxx>
Fixes: f227e3ec3b5c
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
 include/linux/random.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/random.h b/include/linux/random.h
index f310897f051d..9ab7443bd91b 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -11,7 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/once.h>
-#include <linux/percpu.h>
+#include <asm/percpu.h>
 
 #include <uapi/linux/random.h>
 
-- 
2.20.1


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