Re: [patch 15/28] IB/core: disable memory registration of filesystem-dax vmas

[Doug Ledford <dledford@redhat.com>]

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On Wed, 2017-11-29 at 16:10 -0800, akpm@linux-foundation.org wrote:
> From: Dan Williams <dan.j.williams@intel.com>
> Subject: IB/core: disable memory registration of filesystem-dax vmas
> 
> Until there is a solution to the dma-to-dax vs truncate problem it is not
> safe to allow RDMA to create long standing memory registrations against
> filesytem-dax vmas.
> 
> Link: http://lkml.kernel.org/r/151068941011.7446.7766030590347262502.stgit@dwillia2-desk3.amr.corp.intel.com
> Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> Reported-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Acked-by: Jason Gunthorpe <jgg@mellanox.com>
> Cc: Sean Hefty <sean.hefty@intel.com>
> Cc: Doug Ledford <dledford@redhat.com>
> Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
> Cc: Jeff Moyer <jmoyer@redhat.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> Cc: Inki Dae <inki.dae@samsung.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Joonyoung Shim <jy0922.shim@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Acked-by: Doug Ledford <dledford@redhat.com>

> ---
> 
>  drivers/infiniband/core/umem.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff -puN drivers/infiniband/core/umem.c~ib-core-disable-memory-registration-of-fileystem-dax-vmas drivers/infiniband/core/umem.c
> --- a/drivers/infiniband/core/umem.c~ib-core-disable-memory-registration-of-fileystem-dax-vmas
> +++ a/drivers/infiniband/core/umem.c
> @@ -191,7 +191,7 @@ struct ib_umem *ib_umem_get(struct ib_uc
>  	sg_list_start = umem->sg_head.sgl;
>  
>  	while (npages) {
> -		ret = get_user_pages(cur_base,
> +		ret = get_user_pages_longterm(cur_base,
>  				     min_t(unsigned long, npages,
>  					   PAGE_SIZE / sizeof (struct page *)),
>  				     gup_flags, page_list, vma_list);
> _

-- 
Doug Ledford <dledford@redhat.com>
    GPG KeyID: B826A3330E572FDD
    Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD

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