Re: [PATCH v3] RDMA/umem: minor bug fix in error handling path

[Ira Weiny]

On Mon, Mar 04, 2019 at 11:46:45AM -0800, john.hubbard@xxxxxxxxx wrote:
> From: John Hubbard <jhubbard@xxxxxxxxxx>
> 
> 1. Bug fix: fix an off by one error in the code that
> cleans up if it fails to dma-map a page, after having
> done a get_user_pages_remote() on a range of pages.
> 
> 2. Refinement: for that same cleanup code, release_pages()
> is better than put_page() in a loop.
> 
> Cc: Leon Romanovsky <leon@xxxxxxxxxx>
> Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Doug Ledford <dledford@xxxxxxxxxx>
> Cc: linux-rdma@xxxxxxxxxxxxxxx
> Cc: linux-mm@xxxxxxxxx
> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>

I meant...

Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>

<sigh>  just a bit too quick on the keyboard before lunch...  ;-)

Ira


> ---
>  drivers/infiniband/core/umem_odp.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
> index acb882f279cb..d45735b02e07 100644
> --- a/drivers/infiniband/core/umem_odp.c
> +++ b/drivers/infiniband/core/umem_odp.c
> @@ -40,6 +40,7 @@
>  #include <linux/vmalloc.h>
>  #include <linux/hugetlb.h>
>  #include <linux/interval_tree_generic.h>
> +#include <linux/pagemap.h>
>  
>  #include <rdma/ib_verbs.h>
>  #include <rdma/ib_umem.h>
> @@ -684,9 +685,11 @@ 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)
> -				put_page(local_page_list[j]);
> +			/*
> +			 * Release pages, starting at the the first page
> +			 * that experienced an error.
> +			 */
> +			release_pages(&local_page_list[j], npages - j);
>  			break;
>  		}
>  	}
> -- 
> 2.21.0
>