From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [Patch v2 02/15] CIFS: Add support for direct pages in rdata Date: Mon, 25 Jun 2018 15:01:32 -0600 Message-ID: <20180625210132.GB5381@ziepe.ca> References: <20180530194807.31657-1-longli@linuxonhyperv.com> <20180530194807.31657-3-longli@linuxonhyperv.com> <67b8afe7-f5e0-b36a-fcc1-87f1ae08eaa4@talpey.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <67b8afe7-f5e0-b36a-fcc1-87f1ae08eaa4@talpey.com> Sender: linux-kernel-owner@vger.kernel.org To: Tom Talpey Cc: longli@microsoft.com, Steve French , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org List-Id: linux-rdma@vger.kernel.org On Sat, Jun 23, 2018 at 09:50:20PM -0400, Tom Talpey wrote: > On 5/30/2018 3:47 PM, Long Li wrote: > >From: Long Li > > > >Add a function to allocate rdata without allocating pages for data > >transfer. This gives the caller an option to pass a number of pages > >that point to the data buffer. > > > >rdata is still reponsible for free those pages after it's done. > > "Caller" is still responsible? Or is the rdata somehow freeing itself > via another mechanism? > > > > >Signed-off-by: Long Li > > fs/cifs/cifsglob.h | 2 +- > > fs/cifs/file.c | 23 ++++++++++++++++++++--- > > 2 files changed, 21 insertions(+), 4 deletions(-) > > > >diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h > >index 8d16c3e..56864a87 100644 > >+++ b/fs/cifs/cifsglob.h > >@@ -1179,7 +1179,7 @@ struct cifs_readdata { > > unsigned int tailsz; > > unsigned int credits; > > unsigned int nr_pages; > >- struct page *pages[]; > >+ struct page **pages; > > Technically speaking, these are syntactically equivalent. It may not > be worth changing this historic definition. [] is a C99 'flex array', it has a different allocation behavior than ** and is not interchangeable.. Jason