From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BC4C2FC72B1 for ; Sun, 22 Mar 2026 10:03:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 98FCC6B00A5; Sun, 22 Mar 2026 06:03:34 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 940D66B00A6; Sun, 22 Mar 2026 06:03:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 82F1D6B00A7; Sun, 22 Mar 2026 06:03:34 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 752946B00A5 for ; Sun, 22 Mar 2026 06:03:34 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 2FE171407E8 for ; Sun, 22 Mar 2026 10:03:34 +0000 (UTC) X-FDA: 84573261948.20.D45E606 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf22.hostedemail.com (Postfix) with ESMTP id A09D4C0004 for ; Sun, 22 Mar 2026 10:03:32 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=jkwqs+Gd; spf=pass (imf22.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774173812; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=CgV97nrXKS4evIy2Ut/S7Iw2f9T7wvmtiE3+zTq7KKU=; b=LR7mYwD1uOXXbN2p71XcisZITAZorcuKl7HD8SzA5hUQcrHTZ47InRTrt6pqstRw/++0Bq Ega/cjvEA0jbBvnxZYKk1fEeteRO0LICr3t+DGBJmlAViUoqlderCOIyGsxwtI9cvUvz8y aZ5vHbLhk4G/gLiWDJ7g0IiihcUshac= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774173812; a=rsa-sha256; cv=none; b=wt+l33UT/oPAcc3py6gsrWChBEf1aQsanx1juV0+S4PKvd5iBHd4dWH6ypGuc9yo0WRk+d s7yn2NH1q2iTcNWfZafdWQHSSojhFQOqMWuQgf020HD4X4G+drV8qFY4lAHDs/XzrkBDaU rTtqLpZwJgVoZTwmumrXWaqhWqblg80= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=jkwqs+Gd; spf=pass (imf22.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id F2E18600AE; Sun, 22 Mar 2026 10:03:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2E66C19424; Sun, 22 Mar 2026 10:03:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774173811; bh=Fd+lxjtADX8/WZHW/OyQK4X1bNRqeHw1tgTw6r/x3uY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jkwqs+GdaaEAajw166Bmx1YdcGAsvLlGDPSFBV70sxX+r1fX5sTLxCaahqhaG/lUd MUVFpXziVlYbj1lO2VnT9P8q0ZW4amvS6+Pc+bGSziz9pcMYA0Wv3M2IXakVzvhvJM LJGXn61p9spS2dEUse2xD8c2n/9cNe9Fv5vRUXOOoFl5PmWJg8GZ9oxHl+WeAUWa5t xlfltvoQkLoBSKpJUaerBRbWx2DpQAlkTGOhBSNaZvvhwwk6NnJtbolesp9EM9EIFO cNiBxU0nK9gppQK6FZUvlQkCpr/05lk+bGhp/MJUH7Uek1PPbNsbeQkncCWE4VhLOn 7TY1/0TcY3zSQ== Date: Sun, 22 Mar 2026 12:03:20 +0200 From: Mike Rapoport To: "David Hildenbrand (Arm)" Cc: Andrew Morton , Andrea Arcangeli , Axel Rasmussen , Baolin Wang , Hugh Dickins , James Houghton , "Liam R. Howlett" , Lorenzo Stoakes , "Matthew Wilcox (Oracle)" , Michal Hocko , Muchun Song , Nikita Kalyazin , Oscar Salvador , Paolo Bonzini , Peter Xu , Sean Christopherson , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 02/15] userfaultfd: introduce struct mfill_state Message-ID: References: <20260306171815.3160826-1-rppt@kernel.org> <20260306171815.3160826-3-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Stat-Signature: n3dkk7ajchg8dg795bjpu918fo839j7r X-Rspamd-Queue-Id: A09D4C0004 X-Rspamd-Server: rspam03 X-HE-Tag: 1774173812-167383 X-HE-Meta: U2FsdGVkX1//3dYRo2RsKAmy8p/XgsKFqiouchGnmLXWig0K+VVl+zGHknUC16FlG2V0DKjjuQEMoPgADR7VWtF78nt10rcxDEEK/uUNcgXH/4TRAG9Rpl+p9UXFSN923nTAN5tC1qd0kJgQmkvusKO4VYmdsCF+1x7dxC6DkZr9/xo941a9VPdqCMgyk0Kl91RleqjR8F2/mtf2wzTAsxh2pO0zsoV2WNduNiaF4TvEFogep2/dbXZRG4/WDVbAn8xoBS+MjJw0kxPvfJSjj83FpaA+Ya2H5bukf0bT7Xl4KwxZoX9bJBhtg9ZBw9rMRx9FehIKesthG8JjxkOjgH+RVUjBFmo6RRFU3h6x5b5BEc8nzQIKdw508jot65tpzNzaSGZFw+HgF77ohB8rZDwh98dA5QilqiOCGujdXhM+J0av9W5hmU0io8D3rFMNJX/HiOqLhfymSUNd7+rVH+ZGd5VUf+/Sjp8i2qxSff0GtkMQQUWGIFXUJPQzQmpmaSu1eHqKrnpj5szMMoVr9lSZpGIiQoCTPhzsQjbovUAU1eak0jC4bM95H7L9Az5hLVLbOB6WsLTn/RZ0j/+2UnLTLcSOXrtGMKmqW2PDLo8UGyN71o52J0qODRJjGuPnuaZtGTkHli5Cj132Q88M1H1ZHk4kfJEATswJJf8F1fqtu2dUubdU4R29J8hqHV6KGydqhYh0XawpoFKCCVdRZRe19cYRuEGBrIdQfvqZeKG4o0y2VP7K5Q4eWtAJJXpRUundlSjgL9svZUz4NnW7LJ7HyWxUz4IIW9uCn4dwzvb4SCDZM/ObkF1TMi5u2R0APKRVqaGVK4Y+1MbuuSvbsFe5FRFXb+s1R2griVfDoIx8iVEVA0hURPRaRWufz1XOMPziXqc0lTyuQq7vC8ITW9hjbacCJZzvab3R7IMaI9I9v5GYcHfWfqmHPi+DACmda7wnG7dtMzGFeE6eNhZ +Tow1ird jEIzrLWaFy5B6A+3pjR1ZStWRqDEW++sMPQnsPaK1USGbZYClGkIIicsf+MxLiKOge16xWt+SD6U8djT7mxsm3Se6nbHUge6u/Y+9RfBwnO2Iq7Pyam01kTfU3sJ2/8CCeQisACbIFr1o2FR0Q+obIzXRvxfo+aqeGO2/9MlSTHsGvaH4fF/BRMySNYcIkfAyip2xlvzzqxE31NAWfDdng2CFm9GgJQ3K5zqKXHa9TrCD2p3ie4FJoGHTyrfkdRDKFA0u70sUity7cL2hsiECoC6/AZ3V3A++XGtLN064g9TdoAFnsRos9WQPdMfxPs1u6lJPLXQCH1WFAak= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Mar 20, 2026 at 01:43:02PM +0100, David Hildenbrand (Arm) wrote: > On 3/6/26 18:18, Mike Rapoport wrote: > > From: "Mike Rapoport (Microsoft)" > > > > mfill_atomic() passes a lot of parameters down to its callees. > > > > Aggregate them all into mfill_state structure and pass this structure to > > functions that implement various UFFDIO_ commands. > > > > Tracking the state in a structure will allow moving the code that retries > > copying of data for UFFDIO_COPY into mfill_atomic_pte_copy() and make the > > loop in mfill_atomic() identical for all UFFDIO operations on PTE-mapped > > memory. > > > > The mfill_state definition is deliberately local to mm/userfaultfd.c, hence > > shmem_mfill_atomic_pte() is not updated. > > > > Signed-off-by: Mike Rapoport (Microsoft) > > --- > > [...] > > > if (fatal_signal_pending(current)) > > @@ -866,10 +882,10 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx, > > > > out_unlock: > > up_read(&ctx->map_changing_lock); > > - uffd_mfill_unlock(dst_vma); > > + uffd_mfill_unlock(state.vma); > > out: > > - if (folio) > > - folio_put(folio); > > + if (state.folio) > > + folio_put(state.folio); > > VM_WARN_ON_ONCE(copied < 0); > > VM_WARN_ON_ONCE(err > 0); > > VM_WARN_ON_ONCE(!copied && !err); > > return copied ? copied : err; > > I guess, "copied" could be easily avoided by > comparing state.src_addr with start_addr. Yeah, but a dedicated variable is more robust against potential changes in state handling. And it's surely more descriptive and shorter than state.src_addr - src_addr; > Acked-by: David Hildenbrand (Arm) Thanks! > -- > Cheers, > > David -- Sincerely yours, Mike.