Patchwork pkt_sched: gen_estimator: Fix signed integers right-shifts.

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Submitter Jarek Poplawski
Date May 19, 2009, 7:09 p.m.
Message ID <20090519190915.GC2981@ami.dom.local>
Download mbox | patch
Permalink /patch/27410/
State Accepted
Delegated to: David Miller
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Comments

Jarek Poplawski - May 19, 2009, 7:09 p.m.
On Tue, May 19, 2009 at 08:03:24PM +0200, Eric Dumazet wrote:
...
> As I said earlier, I found your concern right, so please submit a patch ?

OK, thanks,
Jarek P.
----------------->
pkt_sched: gen_estimator: Fix signed integers right-shifts.

Right-shifts of signed integers are implementation-defined so unportable.

With feedback from: Eric Dumazet <dada1@cosmosbay.com>

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
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David Miller - May 26, 2009, 5:47 a.m.
From: Jarek Poplawski <jarkao2@gmail.com>
Date: Tue, 19 May 2009 21:09:15 +0200

> pkt_sched: gen_estimator: Fix signed integers right-shifts.
> 
> Right-shifts of signed integers are implementation-defined so unportable.
> 
> With feedback from: Eric Dumazet <dada1@cosmosbay.com>
> 
> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>

Applied to net-next-2.6, thanks!
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Patch

diff -Nurp a/net/core/gen_estimator.c b/net/core/gen_estimator.c
--- a/net/core/gen_estimator.c	2009-05-19 20:33:47.000000000 +0200
+++ b/net/core/gen_estimator.c	2009-05-19 20:40:58.000000000 +0200
@@ -128,12 +128,12 @@  static void est_timer(unsigned long arg)
 		npackets = e->bstats->packets;
 		brate = (nbytes - e->last_bytes)<<(7 - idx);
 		e->last_bytes = nbytes;
-		e->avbps += ((s64)(brate - e->avbps)) >> e->ewma_log;
+		e->avbps += (brate >> e->ewma_log) - (e->avbps >> e->ewma_log);
 		e->rate_est->bps = (e->avbps+0xF)>>5;
 
 		rate = (npackets - e->last_packets)<<(12 - idx);
 		e->last_packets = npackets;
-		e->avpps += ((long)rate - (long)e->avpps) >> e->ewma_log;
+		e->avpps += (rate >> e->ewma_log) - (e->avpps >> e->ewma_log);
 		e->rate_est->pps = (e->avpps+0x1FF)>>10;
 skip:
 		read_unlock(&est_lock);