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Date:   Fri, 27 May 2022 09:35:07 -0600
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To:     Jason Gunthorpe <jgg@ziepe.ca>
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References: <20220407154717.7695-1-logang@deltatee.com>
 <20220407154717.7695-21-logang@deltatee.com>
 <20220527125501.GD2960187@ziepe.ca>
From:   Logan Gunthorpe <logang@deltatee.com>
In-Reply-To: <20220527125501.GD2960187@ziepe.ca>
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Subject: Re: [PATCH v6 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem()
Precedence: bulk


On 2022-05-27 06:55, Jason Gunthorpe wrote:
> On Thu, Apr 07, 2022 at 09:47:16AM -0600, Logan Gunthorpe wrote:
>> +static void pci_p2pdma_unmap_mappings(void *data)
>> +{
>> +	struct pci_dev *pdev = data;
>> +	struct pci_p2pdma *p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
>> +
>> +	/* Ensure no new pages can be allocated in mappings */
>> +	p2pdma->active = false;
>> +	synchronize_rcu();
>> +
>> +	unmap_mapping_range(p2pdma->inode->i_mapping, 0, 0, 1);
>> +
>> +	/*
>> +	 * On some architectures, TLB flushes are done with call_rcu()
>> +	 * so to ensure GUP fast is done with the pages, call synchronize_rcu()
>> +	 * before freeing them.
>> +	 */
>> +	synchronize_rcu();
>> +	pci_p2pdma_free_mappings(p2pdma->inode->i_mapping);
> 
> With the series from Felix getting close this should get updated to
> not set pte_devmap and use proper natural refcounting without any of
> this stuff.

Can you send a link? I'm not sure what you are referring to.

Thanks,

Logan