[PATCH net-next] net/mlx5e: Fix signedness bugs in mlx5e_build_shampo_hd_umr()

[Dan Carpenter <dan.carpenter@oracle.com>]

The error handling has a couple forever loops which will lead to a
crash.  Unsigned values are always greater or equal to zero.

Fixes: 64509b052525 ("net/mlx5e: Add data path for SHAMPO feature")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 96967b0a2441..8cd120666b2d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -543,13 +543,14 @@ static int mlx5e_build_shampo_hd_umr(struct mlx5e_rq *rq,
 				     u16 klm_entries, u16 index)
 {
 	struct mlx5e_shampo_hd *shampo = rq->mpwqe.shampo;
-	u16 entries, pi, i, header_offset, err, wqe_bbs, new_entries;
+	u16 entries, pi, header_offset, err, wqe_bbs, new_entries;
 	u32 lkey = rq->mdev->mlx5e_res.hw_objs.mkey;
 	struct page *page = shampo->last_page;
 	u64 addr = shampo->last_addr;
 	struct mlx5e_dma_info *dma_info;
 	struct mlx5e_umr_wqe *umr_wqe;
 	int headroom;
+	int i;
 
 	headroom = rq->buff.headroom;
 	new_entries = klm_entries - (shampo->pi & (MLX5_UMR_KLM_ALIGNMENT - 1));
@@ -601,8 +602,11 @@ static int mlx5e_build_shampo_hd_umr(struct mlx5e_rq *rq,
 
 err_unmap:
 	while (--i >= 0) {
-		if (--index < 0)
+		if (index == 0)
 			index = shampo->hd_per_wq - 1;
+		else
+			index--;
+
 		dma_info = &shampo->info[index];
 		if (!(i & (MLX5E_SHAMPO_WQ_HEADER_PER_PAGE - 1))) {
 			dma_info->addr = ALIGN_DOWN(dma_info->addr, PAGE_SIZE);
-- 
2.20.1