From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E93EF2F2D; Mon, 26 Aug 2024 05:44:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724651050; cv=none; b=bs0QDOxLnI8AM/aQg/U+w9zFlyUOXSY359oGtDH/lpYd8VH3akgTrZL/vESmfsVXKtR+rsDDNoOzjMPIlPAJMl56Y5bK8q5w0I82QQLY/vohBR39COvrPuYRHijCXVF54fpiPN+gH9nca5tVqTsccqRcSvhz0pAurtVgTUmmpYI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724651050; c=relaxed/simple; bh=a/DVxwbWhN6QKPaU3TDbkvhzlaB/K+gbTapmjkDgN54=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Or0kRjpKf4RK2QQBZl43Sb/TTOywpdd9vL0Y0FHyDK6R1/OveohwDidDQkfGwevPPky5RlkVzCjQdyfNYgqrW9ob3nA2CnxzAuBi0SNsrjKLT7vFkMtxMSlun9/+xraeryoBhBzMKNK+8g6/qdA/6Afc1dmTsDX/jyLRrnh8DCI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=A3k8bNmH; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="A3k8bNmH" Received: from [10.95.75.183] (unknown [167.220.238.215]) by linux.microsoft.com (Postfix) with ESMTPSA id 4841620B7165; Sun, 25 Aug 2024 22:44:06 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 4841620B7165 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1724651048; bh=oQCfduo1C8UnNc5vKeTZWL4Kfc7pwo8X6pgqfHOVdq8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=A3k8bNmHHbWsxzWGzSif5qP21zb1ntghUaQ2guk3Vs4AV/nM9Ue/xeB4/o4bs/OOe 6pi0bsOcjTaxyty02sfOHNmqWLZtd6F+1qqPG70dEfwvXf6xXZWLnAlH4dXxCnie0A Y+AfPmJoYXqt4QbBIM4N03dXiMTv7vbJK4vDlRH8= Message-ID: Date: Mon, 26 Aug 2024 11:14:04 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] Drivers: hv: vmbus: Fix rescind handling in uio_hv_generic To: Michael Kelley , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Greg Kroah-Hartman , Stephen Hemminger Cc: "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Saurabh Sengar References: <20240822110912.13735-1-namjain@linux.microsoft.com> <20240822110912.13735-3-namjain@linux.microsoft.com> Content-Language: en-US From: Naman Jain In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/26/2024 11:10 AM, Michael Kelley wrote: > From: Naman Jain Sent: Sunday, August 25, 2024 10:32 PM >> >> On 8/25/2024 8:27 AM, Michael Kelley wrote: >>> From: Naman Jain Sent: Thursday, August 22, 2024 4:09 AM >>>> >>>> Rescind offer handling relies on rescind callbacks for some of the >>>> resources cleanup, if they are registered. It does not unregister >>>> vmbus device for the primary channel closure, when callback is >>>> registered. >>>> Add logic to unregister vmbus for the primary channel in rescind callback >>>> to ensure channel removal and relid release, and to ensure rescind flag >>>> is false when driver probe happens again. >>>> >>>> Fixes: ca3cda6fcf1e ("uio_hv_generic: add rescind support") >>>> Signed-off-by: Naman Jain >>>> --- >>>> drivers/hv/vmbus_drv.c | 1 + >>>> drivers/uio/uio_hv_generic.c | 7 +++++++ >>>> 2 files changed, 8 insertions(+) >>>> >>>> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c >>>> index c857dc3975be..4bae382a3eb4 100644 >>>> --- a/drivers/hv/vmbus_drv.c >>>> +++ b/drivers/hv/vmbus_drv.c >>>> @@ -1952,6 +1952,7 @@ void vmbus_device_unregister(struct hv_device *device_obj) >>>> */ >>>> device_unregister(&device_obj->device); >>>> } >>>> +EXPORT_SYMBOL_GPL(vmbus_device_unregister); >>>> >>>> #ifdef CONFIG_ACPI >>>> /* >>>> diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c >>>> index c99890c16d29..ea26c0b460d6 100644 >>>> --- a/drivers/uio/uio_hv_generic.c >>>> +++ b/drivers/uio/uio_hv_generic.c >>>> @@ -121,6 +121,13 @@ static void hv_uio_rescind(struct vmbus_channel *channel) >>>> >>>> /* Wake up reader */ >>>> uio_event_notify(&pdata->info); >>>> + >>>> + /* >>>> + * With rescind callback registered, rescind path will not unregister the device >>>> + * when the primary channel is rescinded. Without it, next onoffer msg does not come. >>>> + */ >>>> + if (!channel->primary_channel) >>>> + vmbus_device_unregister(channel->device_obj); >>> >>> When the rescind callback is *not* set, vmbus_onoffer_rescind() makes the >>> call to vmbus_device_unregister(). But it does so bracketed with get_device()/ >>> put_device(). Your code here does not do the bracketing. Is there a reason for >>> the difference? Frankly, I'm not sure why vmbus_onoffer_rescind() does the >>> bracketing, and I can't definitively say if it is really needed. So I guess I'm >>> just asking if you know. :-) >>> >>> Michael >> >> IMHO, we have already NULL checked channel->device_obj and other couple >> of things to make sure we are safe to clean this up. At other places as >> well, I don't see the use of put and get device. So I think its not >> required. I am open to suggestions. >> >> Regards, >> Naman > > OK. I'm good with what you've said, and don't have any further suggestions. > Go with what your patch already has. :-) > > Michael Thank you Michael. I'll wait for some time before posting v2, if there are any more review comments. Regards, Naman