Re: [PATCH] mlx4: Fix chunk sg list overflow in mlx4_alloc_icm()

[Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>]

good catch, applied.  Did this hit you in practice?  I guess it would
take a big coherent ICM allocation, were you getting those?

Also what do you think of this independent cleanup on top of your patch?
It handles the error case for allocation and then avoids having the
common case inside a deeper nested block:

 drivers/net/mlx4/icm.c |   37 +++++++++++++++++++------------------
 1 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/drivers/net/mlx4/icm.c b/drivers/net/mlx4/icm.c
index ef62f17..b07e4de 100644
--- a/drivers/net/mlx4/icm.c
+++ b/drivers/net/mlx4/icm.c
@@ -163,29 +163,30 @@ struct mlx4_icm *mlx4_alloc_icm(struct mlx4_dev *dev, int npages,
 			ret = mlx4_alloc_icm_pages(&chunk->mem[chunk->npages],
 						   cur_order, gfp_mask);
 
-		if (!ret) {
-			++chunk->npages;
-
-			if (coherent)
-				++chunk->nsg;
-			else if (chunk->npages == MLX4_ICM_CHUNK_LEN) {
-				chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
-							chunk->npages,
-							PCI_DMA_BIDIRECTIONAL);
-
-				if (chunk->nsg <= 0)
-					goto fail;
-			}
+		if (ret) {
+			if (--cur_order < 0)
+				goto fail;
+			else
+				continue;
+		}
 
-			if (chunk->npages == MLX4_ICM_CHUNK_LEN)
-				chunk = NULL;
+		++chunk->npages;
 
-			npages -= 1 << cur_order;
-		} else {
-			--cur_order;
-			if (cur_order < 0)
+		if (coherent)
+			++chunk->nsg;
+		else if (chunk->npages == MLX4_ICM_CHUNK_LEN) {
+			chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
+						chunk->npages,
+						PCI_DMA_BIDIRECTIONAL);
+
+			if (chunk->nsg <= 0)
 				goto fail;
 		}
+
+		if (chunk->npages == MLX4_ICM_CHUNK_LEN)
+			chunk = NULL;
+
+		npages -= 1 << cur_order;
 	}
 
 	if (!coherent && chunk) {

-- 
Roland Dreier <rolandd-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org> || For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/index.html
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