From: Long Li <longli@microsoft.com>
To: Tom Talpey <tom@talpey.com>, Jason Gunthorpe <jgg@ziepe.ca>
Cc: Steve French <sfrench@samba.org>,
"linux-cifs@vger.kernel.org" <linux-cifs@vger.kernel.org>,
"samba-technical@lists.samba.org"
<samba-technical@lists.samba.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: RE: [Patch v2 02/15] CIFS: Add support for direct pages in rdata
Date: Wed, 27 Jun 2018 03:21:53 +0000 [thread overview]
Message-ID: <SN4PR2101MB0733CBF80C83C1FA1A4B61E8CE480@SN4PR2101MB0733.namprd21.prod.outlook.com> (raw)
In-Reply-To: <f940d126-237c-963f-f64e-e1eb1e8c6c85@talpey.com>
> Subject: Re: [Patch v2 02/15] CIFS: Add support for direct pages in rdata
>
> 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 <longli@microsoft.com>
> >>>
> >>> 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 <longli@microsoft.com>
> >>> 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.
No, it needs to be declared separately.
With Direct I/O, **pages are allocated and returned from iov_iter_get_pages_alloc() when locking those user pages. They can't be allocated as part of struct cifs_readdata.
next prev parent reply other threads:[~2018-06-27 3:21 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-30 19:47 [Patch v2 00/15] CIFS: Add direct I/O support Long Li
2018-05-30 19:47 ` [Patch v2 01/15] CIFS: Introduce offset for the 1st page in data transfer structures Long Li
2018-05-30 19:47 ` [Patch v2 02/15] CIFS: Add support for direct pages in rdata Long Li
2018-05-30 20:27 ` Ruhl, Michael J
2018-05-30 20:57 ` Long Li
2018-06-24 1:50 ` Tom Talpey
2018-06-25 20:25 ` Long Li
2018-06-25 21:01 ` Jason Gunthorpe
2018-06-26 15:13 ` Tom Talpey
2018-06-27 3:21 ` Long Li [this message]
2018-05-30 19:47 ` [Patch v2 03/15] CIFS: Use offset when reading pages Long Li
2018-06-24 1:58 ` Tom Talpey
2018-06-25 20:27 ` Long Li
2018-05-30 19:47 ` [Patch v2 04/15] CIFS: Add support for direct pages in wdata Long Li
2018-06-24 2:01 ` Tom Talpey
2018-06-25 20:34 ` Long Li
2018-05-30 19:47 ` [Patch v2 05/15] CIFS: Calculate the correct request length based on page offset and tail size Long Li
2018-06-24 2:07 ` Tom Talpey
2018-06-25 21:07 ` Long Li
2018-05-30 19:47 ` [Patch v2 06/15] CIFS: Introduce helper function to get page offset and length in smb_rqst Long Li
2018-06-24 2:09 ` Tom Talpey
2018-06-25 21:14 ` Long Li
2018-06-26 13:16 ` Tom Talpey
2018-06-27 3:24 ` Long Li
2018-05-30 19:47 ` [Patch v2 07/15] CIFS: When sending data on socket, pass the correct page offset Long Li
2018-05-30 19:48 ` [Patch v2 08/15] CIFS: SMBD: Support page offset in RDMA send Long Li
2018-06-24 2:11 ` Tom Talpey
2018-06-25 21:23 ` Long Li
2018-05-30 19:48 ` [Patch v2 09/15] CIFS: SMBD: Support page offset in RDMA recv Long Li
2018-06-24 2:16 ` Tom Talpey
2018-06-25 21:29 ` Long Li
2018-05-30 19:48 ` [Patch v2 10/15] CIFS: SMBD: Support page offset in memory registration Long Li
2018-06-24 2:24 ` Tom Talpey
2018-05-30 19:48 ` [Patch v2 11/15] CIFS: Pass page offset for calculating signature Long Li
2018-06-24 2:27 ` Tom Talpey
2018-06-26 4:15 ` Long Li
2018-05-30 19:48 ` [Patch v2 12/15] CIFS: Pass page offset for encrypting Long Li
2018-06-24 2:28 ` Tom Talpey
2018-05-30 19:48 ` [Patch v2 13/15] CIFS: Add support for direct I/O read Long Li
2018-06-02 5:51 ` kbuild test robot
2018-06-02 7:15 ` kbuild test robot
2018-06-24 2:39 ` Tom Talpey
2018-06-26 4:34 ` Long Li
2018-05-30 19:48 ` [Patch v2 14/15] CIFS: Add support for direct I/O write Long Li
2018-06-24 2:48 ` Tom Talpey
2018-06-26 4:39 ` Long Li
2018-06-26 13:29 ` Tom Talpey
2018-06-27 3:44 ` Long Li
2018-05-30 19:48 ` [Patch v2 15/15] CIFS: Add direct I/O functions to file_operations Long Li
2018-06-07 11:17 ` Pavel Shilovsky
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