From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E5F9D382281; Fri, 13 Mar 2026 12:13:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773404034; cv=none; b=mzbQ0FYTIB86l3e9CSS3lyWVuJo+Caf+CzeFD2PFdDNsdqhj2RWPARomVac32iRqkpO8tn5nl7o4wkHxx/DlqoLe5lM7x4XDkwvKKa+S/Prx8T0q2ejAsmmYOff3kQeIvTf5V5H9eGtQLmBiDyc5g0NqL3sIKD8ksfQXOatKbsk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773404034; c=relaxed/simple; bh=YTSstfxoFHiBrx/2m0P/t3MkgTKyeJ4OyC8gGdFgfg0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Y4WyUdvtvgs5IqdEo9Y/lo2dYWypLQKWi9c+T3/prLW0aOrmqZzGzB13z3YJH+6H3cpuCMEDRj7NFw9FKPMumVBcE0dYLkwSmshidclfin1u8LIO78yvgtrzIodGumXn6OJ6Au1NJ1Fkrd3wSFqum0fjLpbDRsgBNd4Cbp8giys= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DB6dRsTQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DB6dRsTQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84E0DC19421; Fri, 13 Mar 2026 12:13:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773404033; bh=YTSstfxoFHiBrx/2m0P/t3MkgTKyeJ4OyC8gGdFgfg0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DB6dRsTQ08n3qOo3LbHGR1u+n0kWeOhSwb+ENV+XLmec/F+YIQ0TbkSpcxXc4SxOp vHeCf5xRAJLRPuA8hMqRPDPvUtF/PM2u9MLhTGgfq0Ae11MF9gBBhHXccmzR/v45mn xB0zSI5yzSzGTansN0d4x/wNLnx0ndS+Dl4B+JhsaH2l6nIzblj937L039TmtA4rml Dr6J3+ATKRtvGj3D+6JSEUu1hbMWQTHb7OHl+ygHlVZiX0nXmiZRiVxI/hdDdKQZaN hT2R8s+ucuXlNHEKl1rR953D/AJ1NweqQI8U1F2poQTAT5Z/pBYTS88vUfrR7KVI0X 7ogwZcTeTjd3A== Date: Fri, 13 Mar 2026 12:13:42 +0000 From: "Lorenzo Stoakes (Oracle)" To: Andrew Morton Cc: Jonathan Corbet , Clemens Ladisch , Arnd Bergmann , Greg Kroah-Hartman , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Alexander Shishkin , Maxime Coquelin , Alexandre Torgue , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Bodo Stroesser , "Martin K . Petersen" , David Howells , Marc Dionne , Alexander Viro , Christian Brauner , Jan Kara , David Hildenbrand , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-mtd@lists.infradead.org, linux-staging@lists.linux.dev, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-afs@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Ryan Roberts Subject: Re: [PATCH 01/15] mm: various small mmap_prepare cleanups Message-ID: References: <56372fe273f775b26675a04652c1229e14680741.1773346620.git.ljs@kernel.org> <20260312141425.1837736829210f2d0b00cac6@linux-foundation.org> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260312141425.1837736829210f2d0b00cac6@linux-foundation.org> On Thu, Mar 12, 2026 at 02:14:25PM -0700, Andrew Morton wrote: > On Thu, 12 Mar 2026 20:27:16 +0000 "Lorenzo Stoakes (Oracle)" wrote: > > > +int mmap_action_prepare(struct vm_area_desc *desc, > > + struct mmap_action *action) > > + > > { > > switch (action->type) { > > case MMAP_NOTHING: > > - break; > > + return 0; > > case MMAP_REMAP_PFN: > > - remap_pfn_range_prepare(desc, action->remap.start_pfn); > > - break; > > + return remap_pfn_range_prepare(desc, action); > > case MMAP_IO_REMAP_PFN: > > - io_remap_pfn_range_prepare(desc, action->remap.start_pfn, > > - action->remap.size); > > - break; > > + return io_remap_pfn_range_prepare(desc, action); > > } > > } > > EXPORT_SYMBOL(mmap_action_prepare); > > hm, was this the correct version? > > mm/util.c: In function 'mmap_action_prepare': > mm/util.c:1451:1: error: control reaches end of non-void function [-Werror=return-type] > 1451 | } Seems different compiler versions do different things :) In theory we should never hit that but memory corruption and err... rogue drivers? could cause it ofc :) Will fix on respin. > > --- a/mm/util.c~mm-various-small-mmap_prepare-cleanups-fix > +++ a/mm/util.c > @@ -1356,6 +1356,8 @@ int mmap_action_prepare(struct vm_area_d > return remap_pfn_range_prepare(desc, action); > case MMAP_IO_REMAP_PFN: > return io_remap_pfn_range_prepare(desc, action); > + default: > + BUG(); I'd probably prefer a WARN_ON_ONCE(1) return -EBLAH; will think about it on respin. > } > } > EXPORT_SYMBOL(mmap_action_prepare); > _ > Cheers, Lorenzo