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Message-ID: <e27a14f9-ed4d-b98b-940c-2ede0ebcb31b@deltatee.com>
Date:   Thu, 27 Oct 2022 08:22:57 -0600
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To:     Jay Fang <f.fangjian@huawei.com>, linux-kernel@vger.kernel.org,
        linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
        linux-pci@vger.kernel.org, linux-mm@kvack.org
Cc:     Christoph Hellwig <hch@lst.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Don Dutile <ddutile@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Minturn Dave B <dave.b.minturn@intel.com>,
        Jason Ekstrand <jason@jlekstrand.net>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Xiong Jianxin <jianxin.xiong@intel.com>,
        Bjorn Helgaas <helgaas@kernel.org>,
        Ira Weiny <ira.weiny@intel.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Martin Oliveira <martin.oliveira@eideticom.com>,
        Chaitanya Kulkarni <ckulkarnilinux@gmail.com>,
        Ralph Campbell <rcampbell@nvidia.com>,
        Stephen Bates <sbates@raithlin.com>
References: <20221021174116.7200-1-logang@deltatee.com>
 <20221021174116.7200-4-logang@deltatee.com>
 <c73c426f-d9f5-2f17-bb88-b72792103703@huawei.com>
From:   Logan Gunthorpe <logang@deltatee.com>
In-Reply-To: <c73c426f-d9f5-2f17-bb88-b72792103703@huawei.com>
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Subject: Re: [PATCH v11 3/9] iov_iter: introduce
 iov_iter_get_pages_[alloc_]flags()
Precedence: bulk


On 2022-10-27 01:11, Jay Fang wrote:
> On 2022/10/22 1:41, Logan Gunthorpe wrote:
>> Add iov_iter_get_pages_flags() and iov_iter_get_pages_alloc_flags()
>> which take a flags argument that is passed to get_user_pages_fast().
>>
>> This is so that FOLL_PCI_P2PDMA can be passed when appropriate.
>>
>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>> ---
>>  include/linux/uio.h |  6 ++++++
>>  lib/iov_iter.c      | 32 ++++++++++++++++++++++++--------
>>  2 files changed, 30 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/linux/uio.h b/include/linux/uio.h
>> index 2e3134b14ffd..9ede533ce64c 100644
>> --- a/include/linux/uio.h
>> +++ b/include/linux/uio.h
>> @@ -247,8 +247,14 @@ void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode
>>  void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
>>  void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
>>  		     loff_t start, size_t count);
>> +ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
>> +		size_t maxsize, unsigned maxpages, size_t *start,
>> +		unsigned gup_flags);
>>  ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
>>  			size_t maxsize, unsigned maxpages, size_t *start);
>> +ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
>> +		struct page ***pages, size_t maxsize, size_t *start,
>> +		unsigned gup_flags);
>>  ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
>>  			size_t maxsize, size_t *start);
>>  int iov_iter_npages(const struct iov_iter *i, int maxpages);
>> diff --git a/lib/iov_iter.c b/lib/iov_iter.c
>> index c3ca28ca68a6..53efad017f3c 100644
>> --- a/lib/iov_iter.c
>> +++ b/lib/iov_iter.c
>> @@ -1430,7 +1430,8 @@ static struct page *first_bvec_segment(const struct iov_iter *i,
>>  
>>  static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
>>  		   struct page ***pages, size_t maxsize,
>> -		   unsigned int maxpages, size_t *start)
>> +		   unsigned int maxpages, size_t *start,
>> +		   unsigned int gup_flags)
> 
> Hi,
> found some checkpatch warnings, like this:
> WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
> #50: FILE: lib/iov_iter.c:1497:
> +		   size_t *start, unsigned gup_flags)

We usually stick with the choices of the nearby code instead of
the warnings of checkpatch.

Thanks,

Logan