From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] vhost: correctly set bits of dirty pages Date: Mon, 29 Nov 2010 10:18:41 +0200 Message-ID: <20101129081840.GB25496@redhat.com> References: <20101129054819.24923.26439.stgit@dhcp-91-7.nay.redhat.com.englab.nay.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: virtualization@lists.osdl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org To: Jason Wang Return-path: Content-Disposition: inline In-Reply-To: <20101129054819.24923.26439.stgit@dhcp-91-7.nay.redhat.com.englab.nay.redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, Nov 29, 2010 at 01:48:20PM +0800, Jason Wang wrote: > When counting pages we should increase it by 1 instead of VHOST_PAGE_SIZE, > and also make log_write() can correctly process the request across > pages with write_address not start at page boundary. > > Signed-off-by: Jason Wang Thanks, good catch! But let's to it in small steps: first, a small patch to fix the bug: I think this is equivalent, right? Subject: vhost: correctly set bits of dirty pages When counting pages we should increase address by 1 instead of VHOST_PAGE_SIZE, and also make log_write() can correctly process the request across pages with write_address not starting at page boundary. Reported-by: Jason Wang Signed-off-by: Michael S. Tsirkin --- diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 568eb70..d0a3552 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -887,6 +887,7 @@ static int log_write(void __user *log_base, int r; if (!write_length) return 0; + write_length += write_address % VHOST_PAGE_SIZE; write_address /= VHOST_PAGE_SIZE; for (;;) { u64 base = (u64)(unsigned long)log_base; @@ -900,7 +901,7 @@ static int log_write(void __user *log_base, if (write_length <= VHOST_PAGE_SIZE) break; write_length -= VHOST_PAGE_SIZE; - write_address += VHOST_PAGE_SIZE; + write_address += 1; } return r; }