From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 D0005233722 for ; Sun, 31 May 2026 17:23:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780248199; cv=none; b=u5JI7QC66Nm33y5V/5qfCwdBpK+5q8RlArC7VCbUG2mOX7Z+QAVFjGyZWnvt57C1SqW2DWyfBLr9FfPJVBtv9iEkIT99hGJ9tHNCmSkuvN+CB4oh/Qchvx2JLhlYLQCV+lT2h1CKJoviQ9KgzAcREnXBYscxFJgrYuMauirj6kc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780248199; c=relaxed/simple; bh=NfwoBEsehKzaRrWLf2MEp8UR3dchcfYyNPvHYlccvFA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kWDMgixrtMS0Ic/1NWWfqW7qyoJqX1W6MKBPTAsDWkLpDnngzcCHXrULQCObdKqb7f4l/H4UhSnuf8zFZ6NioSeODgEhKuc70xLlvVW97x8mKVnBX8v+eMRhselPn1QQ4JiBruICwka5p+CUVZygDn/7ecpBK3GL9jk39OWJfig= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ca1RH1W0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ca1RH1W0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0F5A1F00893; Sun, 31 May 2026 17:23:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780248198; bh=vWAGQnAYKVkZZw1sMg+oHC1jQ2+XzJrS7x/6sJVGKqo=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ca1RH1W0Wxcxr79uTWniFeOlpGbGmfBugPJpJujCYKxlu04bclqmTJNhVHw7h9pB+ DHKoSm+5eMNlOfS/0BdWb3P+ZgZyY7Es1yP2ZxfcQowENGTcH+IJ+/WvGTev9AG9vv nvKrx7mP71hNGkog1Z7MvYiva/eGZgzKNAw/+od3xHgc+OgsMy/YQKRDCpvZ4tPdEh kbQk2nqBMU4DR7RCFpG+etqh6ctPzXYT+SgqxXXPFhe5PAmzvFoACgwHTJXe35yd+w 7/gykJ+mTXClHcsc1jWX034jHy6qVDn62L0Go4TnuMhshnHWcFGfFEAvzg7wXxZZMb 0w2gujZezj1ZQ== Message-ID: Date: Sun, 31 May 2026 19:23:15 +0200 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 v2] mm/gup: honour FOLL_PIN in NOMMU __get_user_pages_locked() To: Andrew Morton Cc: Greg Kroah-Hartman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jason Gunthorpe , John Hubbard , Peter Xu References: <2026042303-vendor-outright-b9d2@gregkh> <20260424063817.552a894d4b5bfa4de40792fa@linux-foundation.org> <20260526173550.927ba4ba517e9af5a6d2c6bf@linux-foundation.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/27/26 02:35, Andrew Morton wrote: > On Fri, 24 Apr 2026 16:19:32 +0200 "David Hildenbrand (Arm)" wrote: > >> On 4/24/26 15:38, Andrew Morton wrote: >>> >>> >>> Battle of the bots? >>> https://sashiko.dev/#/patchset/2026042303-vendor-outright-b9d2@gregkh >> >> It references the >> >> if (pages && !(flags & FOLL_PIN)) >> flags |= FOLL_GET; >> >> I'm not sure if there is actual NOMMU code that triggers it. For example, >> uprobes uses that pattern, but I suspect that that's not a thing on NOMMU. >> >> >> Probably best to just squash: >> >> diff --git a/mm/gup.c b/mm/gup.c >> index ad9ded39609c..44bd28cf6e00 100644 >> --- a/mm/gup.c >> +++ b/mm/gup.c >> @@ -1988,6 +1988,9 @@ static long __get_user_pages_locked(struct mm_struct *mm, >> unsigned long start, >> if (!nr_pages) >> return 0; >> >> + if (pages && !(foll_flags & FOLL_PIN)) >> + foll_flags |= FOLL_GET; >> + >> /* >> * The internal caller expects GUP to manage the lock internally and the >> * lock must be released when this returns. > > Nothing happened. > > Should we proceed with this as-is? No let's squash what I provided. Probably a resend would be best. If greg is too busy I can give it a try tomorrow. -- Cheers, David