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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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260312141425.1837736829210f2d0b00cac6@linux-foundation.org> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 9BF9240016 X-Stat-Signature: kguqk58yiwgg41strynbts7ou3ujcpec X-Rspam-User: X-HE-Tag: 1773404034-557993 X-HE-Meta: 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 Bw4S7Q/Z EKow6Z8W+vRFctiNNLd7ZDw5gm0V4Tk6gA52c2CPKNvoUaJYUhkLnN6l4tah3ZNPX5tV/ajU/9kheUdEa7qNV66El8iWrNOjdtMBOD61l470tqN+Q56Gx1WfQX+XPqYqX2Pt0mFzrdWZr1Wu8bMe43siRn+KlVM4hT9iBnx6MoMoCzd+MoFjmiWYGY6F7CVk1EIQoOa2/sgYvdro843FugXn96u46YUKSVERZWr6BB4n7w97npRPpUqrl1ABFgCDIktCqN/vvcW35nB8FXjtx6WJScumKzzFRUlF7bg9jzZ+H6gG5Uq3WcvTNpiRPDpRxcHdCWXIlHVImfxnJqHiuAYP/E1VZgRQkh0bX Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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