[PATCH net v2] net: wwan: t7xx: Fix off-by-one error in t7xx_dpmaif_rx_buf_alloc()

[Jinjie Ruan]

The error path in t7xx_dpmaif_rx_buf_alloc(), free and unmap the already
allocated and mapped skb in a loop, but the loop condition terminates when
the index reaches zero, which fails to free the first allocated skb at
index zero.

Check for >= 0 so that skb at index 0 is freed as well.

Fixes: d642b012df70 ("net: wwan: t7xx: Add data path interface")
Suggested-by: Sergey Ryazanov <ryazanov.s.a@xxxxxxxxx>
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
v2:
- Update the commit title.
- Declare i as signed to avoid the endless loop.
---
 drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c b/drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c
index 210d84c67ef9..45e7833965b1 100644
--- a/drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c
+++ b/drivers/net/wwan/t7xx/t7xx_hif_dpmaif_rx.c
@@ -166,8 +166,8 @@ int t7xx_dpmaif_rx_buf_alloc(struct dpmaif_ctrl *dpmaif_ctrl,
 			     const unsigned int q_num, const unsigned int buf_cnt,
 			     const bool initial)
 {
-	unsigned int i, bat_cnt, bat_max_cnt, bat_start_idx;
-	int ret;
+	unsigned int bat_cnt, bat_max_cnt, bat_start_idx;
+	int ret, i;
 
 	if (!buf_cnt || buf_cnt > bat_req->bat_size_cnt)
 		return -EINVAL;
@@ -226,7 +226,7 @@ int t7xx_dpmaif_rx_buf_alloc(struct dpmaif_ctrl *dpmaif_ctrl,
 	return 0;
 
 err_unmap_skbs:
-	while (--i > 0)
+	while (--i >= 0)
 		t7xx_unmap_bat_skb(dpmaif_ctrl->dev, bat_req->bat_skb, i);
 
 	return ret;
-- 
2.34.1