From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender5-op-o11.zoho.com (sender5-op-o11.zoho.com [165.173.182.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C05C2470E96 for ; Fri, 9 Oct 2026 18:47:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=165.173.182.11 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791571622; cv=pass; b=nxvoHFKc+AugWrRxCZ+/hbw98nn/x2lWZoCc1oAyDdT6xrriYAZH1n26A4EHG/7L72EysXj6KLfYS5CM5j0SvKFDUkNbySx6B+jtJkW6VhCVezS4eBB2GbMXKQ2ztPi/mNHKGm5z7ARc460pkA5ClD03J+m6nArQ8bwU2ws2z7g= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791571622; c=relaxed/simple; bh=+OhdLoeV7VemjSuPnl9qnv3JFlY77j8/3hG/kgAPlgI=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=sEs0lB5JvViJdomWJa0C7UZRynUBp/ZdNfX4nckYWipHtKgd2p3Esy02VaBWPywM1bX08VZIUbtm3Ux29y/Y2w9refq+1D+aRfckM3jKbn1rxZJFJ1++DoPGQy64jRxSixCZbyRFnu4zsa09/NbnIeiJxxt0LnGoisbNm+eTPYo= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=dmitry.osipenko@collabora.com header.b=KOt+7J33; arc=pass smtp.client-ip=165.173.182.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=dmitry.osipenko@collabora.com header.b="KOt+7J33" ARC-Seal: i=1; a=rsa-sha256; t=1791571616; cv=none; d=zohomail.com; s=zohoarc; b=bgSl2cLdivPj0FGLrRjRXccvLNkUXeT8tdAb122PXeae/keTuv4+QZSIIPKfHD1GvjehpWdNOI7G9QGhXDigTq6z4Bmp9dZsmgDgG5LGOQ/PyKjJzf3ngXFn5rVMMbTjevMjL2dyKBpoRHkYzDxvXtJetJuL5/NluyJIQHHNb2A= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1791571616; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=sNaQMcbvojwqaa6CpBCGayYt2Qv26FQpb2UDUBNOFG8=; b=BfZyZ2/bM2OAAcoVcnOZ01Xq2K5WG7KIYNZ2ufp6e1A7/PbafYKNnDHCC05InIKai7f2WAaa6OsWH8zUqP7uYpqwasP1PEKlnVxuXLdK8ivxdZcKvK2+NyExpTukh0n+iNTfRBK1xEcdxYL2Elr2493sSsKhC8r0CDEP6NsNWGI= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=dmitry.osipenko@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1791571616; s=zohomail; d=collabora.com; i=dmitry.osipenko@collabora.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:From:From:To:To:Cc:Cc:In-Reply-To:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=sNaQMcbvojwqaa6CpBCGayYt2Qv26FQpb2UDUBNOFG8=; b=KOt+7J3380H/WWmsyxhoxHbmGrc1pwnr9bBQgY9PXU4jnGjfRXCF+P1/eFRl1u3q Yey7EY0mfrjpjQbtBOYFKbCb43xufiJ18ZSu2sbUfynrVyPVHnuYzh77Orc+Z48dcja zUNaIOdIpl3PtfFtb6MePPhaKtWoguZm6nUBEJmw= Received: by smtp.zohomail.com with SMTPS id 1791571615413714.4154527093252; Fri, 9 Oct 2026 11:46:55 -0700 (PDT) Message-ID: Date: Fri, 9 Oct 2026 21:46:51 +0300 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v9 3/4] drm/virtio: implement userptr resource support From: Dmitry Osipenko To: Honglei Huang , odaki@rsg.ci.i.u-tokyo.ac.jp, airlied@redhat.com, kraxel@redhat.com Cc: gurchetansingh@chromium.org, olvaffe@gmail.com, Ray.Huang@amd.com, dri-devel@lists.freedesktop.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260924095556.1326164-1-honghuan@amd.com> <20260924095556.1326164-4-honghuan@amd.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ZohoMailClient: External 09.10.2026 21:38, Dmitry Osipenko пишет: > 24.09.2026 12:55, Honglei Huang пишет: >> + mm = current->mm; >> + mmgrab(mm); >> + lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; >> + new_pinned = atomic64_add_return(userptr->npages, &mm->pinned_vm); >> + if (new_pinned < 0 || >> + (new_pinned > lock_limit && !capable(CAP_IPC_LOCK))) { >> + atomic64_sub(userptr->npages, &mm->pinned_vm) > > At a quick glance over other kernel code touching pinned_vm, nobody else > check for new_pinned < 0 and then doing atomic64_sub() for the negative > value will be incorrect. Though no, negative will restore pinned_vm. Still neg looks confusing and shouldn't be needed as such overflow shouldn't be possible. -- Best regards, Dmitry