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 D32BA3E3C73; Mon, 8 Jun 2026 18:42:30 +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=1780944151; cv=none; b=lKQ12s2B6g2fQlm4+J0PVwSyu/sPK4zSJnDDNK/atVCuw26JzG/emcE7dPO3BxYMZ1z6fLpX53iXNXs0hIDKDLHFuXXMy42DdfvVuN4yuKlEWhzNtIG4eAhLKrcoWDuJ2lP4zJjlEVbdCCTrWJs6q/mzbUIJ95KWu8B/xxXiekY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780944151; c=relaxed/simple; bh=Qn/8Hql1frodTukYIvzJEFhJnbdEad1dXeCLKcJl3hc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=FGLnlMjpWJJiRkN8J9Trz9kjDBnYLMe8jNEYsJCnJ1Yl9ndaYI8wHMTQCAaXzuBrMxDiKv8O0SZBgJuajw4Y2rGM/5VYuraVmNkbM1QLR974V7ZCkWyDYtkaK6I4Z/yMcFvr900mtHZmlE8s5c3JWKf9PNORLL0XPZGU58nzENg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z0HZKfaV; 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="Z0HZKfaV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E01E01F00893; Mon, 8 Jun 2026 18:42:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780944150; bh=QTurqwAonbHqex2EQ+XolDLMRIFlrC/dSa0htwEu82g=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Z0HZKfaVAqzMbu2qFZkeUKh44K090vkZHhr2CreO4dU8mj5GgCXvKHTG7KXIGt93i RBGKr5AwaZ656gtjGUMPa1zrG09sZj9D7+00WSGAuTa62mfSlSFn008n5LgoEynZUV gO6DlohPsodQ7MCnG4Pu8vQrEbJZRt0J+VCPvcwiKk0Yl30jqnhE+LLQcXAqIp/9fV pTs+I6Hi8Ft1phAEeMZW8xdMiamy4aru//jt7fMVDpwSn6Gtyyce9pTg0u/8xm40bb g2ave37PYfMp9QvraQN7iN4kpvyx1Z5CCr0zwk2++i/A7FiIn86nyxOPs2AoLaDrQj xwTvnsa49ol4Q== Message-ID: Date: Mon, 8 Jun 2026 20:42:24 +0200 Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] vmsplice: make vmsplice a trivial wrapper for preadv2/pwritev2 To: Alexander Gordeev , Askar Safin Cc: linux-fsdevel@vger.kernel.org, Christian Brauner , Alexander Viro , Jan Kara , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, netdev@vger.kernel.org, Linus Torvalds , Matthew Wilcox , Jens Axboe , Christoph Hellwig , David Howells , Andrew Morton , Pedro Falcato , Miklos Szeredi , patches@lists.linux.dev, linux-s390@vger.kernel.org, linux-next@vger.kernel.org References: <20260531010107.1953702-1-safinaskar@gmail.com> <20260531010107.1953702-3-safinaskar@gmail.com> <20260608171917.3195488Afc-agordeev@linux.ibm.com> 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 6/8/26 19:19, Alexander Gordeev wrote: > On Sun, May 31, 2026 at 01:01:06AM +0000, Askar Safin wrote: >> vmsplice behavior on writable pipe became equivalent to pwritev2. >> vmsplice behavior on readable pipe already was nearly >> equivalent to preadv2, but I made this explicit. I. e. I made it >> obvious from code that vmsplice now is equivalent to preadv2/pwritev2. >> >> Also I moved vmsplice to fs/read_write.c, because now it arguably >> belongs there. >> >> Note that SPLICE_F_NONBLOCK behavior slightly changed: previously >> vmsplice ignored whether the pipe was opened with O_NONBLOCK, and mode >> of operation depended on whether SPLICE_F_NONBLOCK was passed only. >> Now the operation will be non-blocking if O_NONBLOCK was passed when >> opening *or* SPLICE_F_NONBLOCK was passed to vmsplice. Previous >> behavior was arguably buggy, and new behavior is arguably better. >> >> Now SPLICE_F_GIFT is always ignored by all 3 syscalls: splice, tee >> and vmsplice. >> >> Signed-off-by: Askar Safin >> --- >> fs/read_write.c | 23 +++++ >> fs/splice.c | 192 +-------------------------------------- >> include/linux/skbuff.h | 4 +- >> include/linux/splice.h | 2 +- >> include/linux/syscalls.h | 4 +- >> 5 files changed, 29 insertions(+), 196 deletions(-) > > Hi All, > > This patch as commit e2c0b2368081b ("vmsplice: make vmsplice a trivial > wrapper for preadv2/pwritev2") in linux-next on s390 causes the selftest > tools/testing/selftests/mm/cow.c to hang: > > # [RUN] vmsplice() + unmap in child ... with PTE-mapped THP (128 kB) > > Recently there has been changes in THP area, so the problem is not > necessary linked to this patch per se. If we reach 128 kB, then 64 kB likely worked. Which might hint at a similar problem as found by the vmsplice01 ltp test case (blocking instead of returning once the pipe is full). https://lore.kernel.org/r/20260603-raumfahrt-unmerklich-ertrugen-c4ecae70d5f9@brauner -- Cheers, David