From: Long Li <longli@microsoft.com>
To: Tom Talpey <tom@talpey.com>, 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 06/15] CIFS: Introduce helper function to get page offset and length in smb_rqst
Date: Wed, 27 Jun 2018 03:24:09 +0000 [thread overview]
Message-ID: <SN4PR2101MB0733196B6565A7BF6F0008BCCE480@SN4PR2101MB0733.namprd21.prod.outlook.com> (raw)
In-Reply-To: <33a2f951-10fd-fa94-4fb1-cade7f72cd77@talpey.com>
> Subject: Re: [Patch v2 06/15] CIFS: Introduce helper function to get page
> offset and length in smb_rqst
>
> On 6/25/2018 5:14 PM, Long Li wrote:
> >> Subject: Re: [Patch v2 06/15] CIFS: Introduce helper function to get
> >> page offset and length in smb_rqst
> >>
> >> On 5/30/2018 3:47 PM, Long Li wrote:
> >>> From: Long Li <longli@microsoft.com>
> >>>
> >>> Introduce a function rqst_page_get_length to return the page offset
> >>> and length for a given page in smb_rqst. This function is to be used
> >>> by following patches.
> >>>
> >>> Signed-off-by: Long Li <longli@microsoft.com>
> >>> ---
> >>> fs/cifs/cifsproto.h | 3 +++
> >>> fs/cifs/misc.c | 17 +++++++++++++++++
> >>> 2 files changed, 20 insertions(+)
> >>>
> >>> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index
> >>> 7933c5f..89dda14 100644
> >>> --- a/fs/cifs/cifsproto.h
> >>> +++ b/fs/cifs/cifsproto.h
> >>> @@ -557,4 +557,7 @@ int cifs_alloc_hash(const char *name, struct
> >> crypto_shash **shash,
> >>> struct sdesc **sdesc);
> >>> void cifs_free_hash(struct crypto_shash **shash, struct sdesc
> >>> **sdesc);
> >>>
> >>> +extern void rqst_page_get_length(struct smb_rqst *rqst, unsigned
> >>> +int
> >> page,
> >>> + unsigned int *len, unsigned int *offset);
> >>> +
> >>> #endif /* _CIFSPROTO_H */
> >>> diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 96849b5..e951417
> >>> 100644
> >>> --- a/fs/cifs/misc.c
> >>> +++ b/fs/cifs/misc.c
> >>> @@ -905,3 +905,20 @@ cifs_free_hash(struct crypto_shash **shash,
> >> struct sdesc **sdesc)
> >>> crypto_free_shash(*shash);
> >>> *shash = NULL;
> >>> }
> >>> +
> >>> +/**
> >>> + * rqst_page_get_length - obtain the length and offset for a page
> >>> +in smb_rqst
> >>> + * Input: rqst - a smb_rqst, page - a page index for rqst
> >>> + * Output: *len - the length for this page, *offset - the offset
> >>> +for this page */ void rqst_page_get_length(struct smb_rqst *rqst,
> >>> +unsigned int page,
> >>> + unsigned int *len, unsigned int *offset) {
> >>> + *len = rqst->rq_pagesz;
> >>> + *offset = (page == 0) ? rqst->rq_offset : 0;
> >>
> >> Really? Page 0 always has a zero offset??
> >
> > I think you are misreading this line. The offset for page 0 is rq_offset, the
> offset for all subsequent pages are 0.
>
> Ah, yes, sorry I did read it incorrectly.
> >>> +
> >>> + if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
> >>> + *len = rqst->rq_tailsz;
> >>> + else if (page == 0)
> >>> + *len = rqst->rq_pagesz - rqst->rq_offset; }
> >>>
> >>
> >> This subroutine does what patch 5 does inline. Why not push this
> >> patch up in the sequence and use the helper?
> >
> > This is actually a little different. This function returns the length and offset
> for a given page in the request. There might be multiple pages in a request.
>
> Ok, but I still think there is quite a bit of inline computation of this stuff that
> would more clearly and more robustly be done in a set of common functions.
> If someone ever touches the code to support a new upper layer, or even
> integrate with more complex compounding, things will get ugly fast.
>
> > The other function calculates the total length of all the pages in a request.
>
> Again, a great candidate for a common set of subroutines, IMO.
I will look into this. The reason I didn't make a common function is that this is the only patch that will use it in this way.
next prev parent reply other threads:[~2018-06-27 3:24 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
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 [this message]
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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