Re: [PATCH RFC 2/5] vringfd base/offset

From: Anthony Liguori
Date: Sat Apr 05 2008 - 13:19:22 EST


Rusty Russell wrote:
It turns out the lguest (and possibly kvm) want the addresses in the
ring buffer to only cover a certain part of memory, and be offset.

It makes sense that this be an ioctl.

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>


<snip>

@@ -208,12 +232,15 @@ int vring_get_buffer(struct vring_info *
out_len = &dummy;
*in_len = *out_len = 0;
-
- if (unlikely(get_user(head, &vr->ring.avail->ring[head]) != 0))
+
+ if (unlikely(get_user(head, &vr->ring.avail->ring[vr->last_avail
+ % vr->ring.num])))

Why not & with vr->mask for the sake of consistency with the rest of the code.

Regards,

Anthony Liguori
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