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Commit 851b10d6 authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by David S. Miller
Browse files

net/mlx4_en: do batched put_page using atomic_sub 



This patch fixes couple error paths after allocation failures.
Atomic set of page reference counter is safe only if it is zero,
otherwise set can race with any speculative get_page_unless_zero.

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 04aeb56a

drivers/net/ethernet/mellanox/mlx4/en_rx.c

+6 −2
Original line number Diff line number Diff line
@@ -126,7 +126,9 @@ static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv, 
			dma_unmap_page(priv->ddev, page_alloc[i].dma,

				page_alloc[i].page_size, PCI_DMA_FROMDEVICE);

			page = page_alloc[i].page;

			set_page_count(page, 1);

			/* Revert changes done by mlx4_alloc_pages */

			page_ref_sub(page, page_alloc[i].page_size /

					   priv->frag_info[i].frag_stride - 1);

			put_page(page);

		}

	}
@@ -176,7 +178,9 @@ static int mlx4_en_init_allocator(struct mlx4_en_priv *priv, 
		dma_unmap_page(priv->ddev, page_alloc->dma,

			       page_alloc->page_size, PCI_DMA_FROMDEVICE);

		page = page_alloc->page;

		set_page_count(page, 1);

		/* Revert changes done by mlx4_alloc_pages */

		page_ref_sub(page, page_alloc->page_size /

				   priv->frag_info[i].frag_stride - 1);

		put_page(page);

		page_alloc->page = NULL;

	}