From mboxrd@z Thu Jan  1 00:00:00 1970
From: Olaf Hering <olaf@aepfle.de>
Subject: Re: bogus wrap check in xen-netback
Date: Wed, 25 Apr 2018 09:39:24 +0200
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To: Juergen Gross <jgross@suse.com>
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Am Wed, 25 Apr 2018 09:28:38 +0200
schrieb Juergen Gross <jgross@suse.com>:

> Why? (u16)0 - (u16)65400 =3D=3D 136

My helloworld.c shows that ushort gets promoted to uint, unless it is done =
like that:

-               if (queue->tx.sring->req_prod - queue->tx.req_cons >
-                   XEN_NETIF_TX_RING_SIZE) {
+               idx =3D queue->tx.sring->req_prod - queue->tx.req_cons;=20
+               if ( idx > XEN_NETIF_TX_RING_SIZE) {

Olaf

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