From: Matt Mackall Date: Tue, 29 Apr 2008 08:03:03 +0000 (-0700) Subject: random: remove some prefetch logic X-Git-Tag: accepted/tizen/common/20141203.182822~22742 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6d38b827400d7c02bce391f90d044e4c57d5bc1e;p=platform%2Fkernel%2Flinux-arm64.git random: remove some prefetch logic The urandom output pool (ie the fast path) fits in one cacheline, so this is pretty unnecessary. Further, the output path has already fetched the entire pool to hash it before calling in here. (This was the only user of prefetch_range in the kernel, and it passed in words rather than bytes!) Signed-off-by: Matt Mackall Cc: Theodore Ts'o Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/char/random.c b/drivers/char/random.c index 3823cb2..a754132 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -457,7 +457,7 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in, unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5; int input_rotate; int wordmask = r->poolinfo->poolwords - 1; - __u32 w, next_w; + __u32 w; unsigned long flags; /* Taps are constant, so we can load them without holding r->lock. */ @@ -466,17 +466,13 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in, tap3 = r->poolinfo->tap3; tap4 = r->poolinfo->tap4; tap5 = r->poolinfo->tap5; - next_w = *in++; spin_lock_irqsave(&r->lock, flags); - prefetch_range(r->pool, wordmask); input_rotate = r->input_rotate; add_ptr = r->add_ptr; while (nwords--) { - w = rol32(next_w, input_rotate & 31); - if (nwords > 0) - next_w = *in++; + w = rol32(*in++, input_rotate & 31); i = add_ptr = (add_ptr - 1) & wordmask; /* XOR in the various taps */