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Subject: Re: [PATCH v2] RDMA/umem: minor bug fix and cleanup in error handling
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To:     Jason Gunthorpe <jgg@ziepe.ca>,
        Artemy Kovalyov <artemyko@mellanox.com>
CC:     Ira Weiny <ira.weiny@intel.com>,
        "john.hubbard@gmail.com" <john.hubbard@gmail.com>,
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From:   John Hubbard <jhubbard@nvidia.com>
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On 3/5/19 5:32 PM, Jason Gunthorpe wrote:
> On Wed, Mar 06, 2019 at 03:02:36AM +0200, Artemy Kovalyov wrote:
>>
>>
>> On 04/03/2019 00:37, John Hubbard wrote:
>>> On 3/3/19 1:52 AM, Artemy Kovalyov wrote:
>>>>
>>>>
>>>> On 02/03/2019 21:44, Ira Weiny wrote:
>>>>>
>>>>> On Sat, Mar 02, 2019 at 12:24:35PM -0800, john.hubbard@gmail.com wrote:
>>>>>> From: John Hubbard <jhubbard@nvidia.com>
>>>>>>
>>>>>> ...
>>>
>>> OK, thanks for explaining! Artemy, while you're here, any thoughts about the
>>> release_pages, and the change of the starting point, from the other part of the
>>> patch:
>>>
>>> @@ -684,9 +677,11 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp,
>>> u64 user_virt,
>>> 	mutex_unlock(&umem_odp->umem_mutex);
>>>
>>>    		if (ret < 0) {
>>> -			/* Release left over pages when handling errors. */
>>> -			for (++j; j < npages; ++j)
>> release_pages() is an optimized batch put_page() so it's ok.
>> but! release starting from page next to one cause failure in
>> ib_umem_odp_map_dma_single_page() is correct because failure flow of this
>> functions already called put_page().
>> So release_pages(&local_page_list[j+1], npages - j-1) would be correct.
> 
> Someone send a fixup patch please...
> 
> Jason

Yeah, I'm on it. Just need to double-check that this is the case. But Jason,
you're confirming it already, so that helps too.

Patch coming shortly.

thanks,
-- 
John Hubbard
NVIDIA