From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Talpey Subject: Re: [Patch v2 02/15] CIFS: Add support for direct pages in rdata Date: Tue, 26 Jun 2018 11:13:46 -0400 Message-ID: References: <20180530194807.31657-1-longli@linuxonhyperv.com> <20180530194807.31657-3-longli@linuxonhyperv.com> <67b8afe7-f5e0-b36a-fcc1-87f1ae08eaa4@talpey.com> <20180625210132.GB5381@ziepe.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180625210132.GB5381@ziepe.ca> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jason Gunthorpe 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 6/25/2018 5:01 PM, Jason Gunthorpe wrote: > 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.. In that case, it's an even better reason to not change the declaration. Tom.