wifi: ath12k: mhi: fix potential memory leak in ath12k_mhi_register()

[ Upstream commit 47c27aa ]

mhi_alloc_controller() allocates a memory space for mhi_ctrl. When some
errors occur, mhi_ctrl should be freed by mhi_free_controller() and set
ab_pci->mhi_ctrl = NULL.

We can fix it by calling mhi_free_controller() when the failure happens
and set ab_pci->mhi_ctrl = NULL in all of the places where we call
mhi_free_controller().

Signed-off-by: Ma Ke <make_ruc2021@163.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230922021036.3604157-1-make_ruc2021@163.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/wireless/ath/ath12k/mhi.c

@@ -370,8 +370,7 @@ int ath12k_mhi_register(struct ath12k_pci *ab_pci)
 	ret = ath12k_mhi_get_msi(ab_pci);
 	if (ret) {
 		ath12k_err(ab, "failed to get msi for mhi\n");
-		mhi_free_controller(mhi_ctrl);
-		return ret;
+		goto free_controller;
 	}
 
 	mhi_ctrl->iova_start = 0;
@@ -388,11 +387,15 @@ int ath12k_mhi_register(struct ath12k_pci *ab_pci)
 	ret = mhi_register_controller(mhi_ctrl, ab->hw_params->mhi_config);
 	if (ret) {
 		ath12k_err(ab, "failed to register to mhi bus, err = %d\n", ret);
-		mhi_free_controller(mhi_ctrl);
-		return ret;
+		goto free_controller;
 	}
 
 	return 0;
+
+free_controller:
+	mhi_free_controller(mhi_ctrl);
+	ab_pci->mhi_ctrl = NULL;
+	return ret;
 }
 
 void ath12k_mhi_unregister(struct ath12k_pci *ab_pci)