net/mlx4: Remove BUG_ON from ICM allocation routine

[ Upstream commit c1d5f8ff ]

This patch removes BUG_ON() macro from mlx4_alloc_icm_coherent()
by checking DMA address alignment in advance and performing proper
folding in case of error.

Fixes: 5b0bf5e2 ("mlx4_core: Support ICM tables in coherent memory")
Reported-by: Ozgur Karatas <okaratas@member.fsf.org>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

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

@@ -118,8 +118,13 @@ static int mlx4_alloc_icm_coherent(struct device *dev, struct scatterlist *mem,
 	if (!buf)
 		return -ENOMEM;
 
+	if (offset_in_page(buf)) {
+		dma_free_coherent(dev, PAGE_SIZE << order,
+				  buf, sg_dma_address(mem));
+		return -ENOMEM;
+	}
+
 	sg_set_buf(mem, buf, PAGE_SIZE << order);
-	BUG_ON(mem->offset);
 	sg_dma_len(mem) = PAGE_SIZE << order;
 	return 0;
 }