net: hns3: Fix potential null pointer defererence of null ae_dev

mainline inclusion
from mainline-v5.13-rc1
commit d0494135
category: bugfix
bugzilla: 173966
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d0494135f94c7ab5a9cf7a9094fbb233275c7ba6

----------------------------------------------------------------------

The reset_prepare and reset_done calls have a null pointer check
on ae_dev however ae_dev is being dereferenced via the call to
ns3_is_phys_func with the ae->pdev argument. Fix this by performing
a null pointer check on ae_dev and hence short-circuiting the
dereference to ae_dev on the call to ns3_is_phys_func.

Addresses-Coverity: ("Dereference before null check")
Fixes: 715c58e9 ("net: hns3: add suspend and resume pm_ops")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Reviewed-by: NYongxin Li <liyongxin1@huawei.com>
Signed-off-by: NJunxin Chen <chenjunxin1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

@@ -2366,9 +2366,9 @@ static int __maybe_unused hns3_suspend(struct device *dev)
 {
 	struct hnae3_ae_dev *ae_dev = dev_get_drvdata(dev);
 
-	if (hns3_is_phys_func(ae_dev->pdev)) {
+	if (ae_dev && hns3_is_phys_func(ae_dev->pdev)) {
 		dev_info(dev, "Begin to suspend.\n");
-		if (ae_dev && ae_dev->ops && ae_dev->ops->reset_prepare)
+		if (ae_dev->ops && ae_dev->ops->reset_prepare)
 			ae_dev->ops->reset_prepare(ae_dev, HNAE3_FUNC_RESET);
 	}
 
@@ -2379,9 +2379,9 @@ static int __maybe_unused hns3_resume(struct device *dev)
 {
 	struct hnae3_ae_dev *ae_dev = dev_get_drvdata(dev);
 
-	if (hns3_is_phys_func(ae_dev->pdev)) {
+	if (ae_dev && hns3_is_phys_func(ae_dev->pdev)) {
 		dev_info(dev, "Begin to resume.\n");
-		if (ae_dev && ae_dev->ops && ae_dev->ops->reset_done)
+		if (ae_dev->ops && ae_dev->ops->reset_done)
 			ae_dev->ops->reset_done(ae_dev);
 	}