[PATCH v4 05/18] PCI: dwc: Deallocate EPC memory on EP init error

[Serge Semin <Sergey.Semin@baikalelectronics.ru>]

If the dw_pcie_ep_init() method fails to perform any action after the EPC
memory is initialized and the MSI memory region is allocated, the later
parts won't be undone thus causing the memory leak.  Let's fix that by
introducing the cleanup-on-error path in the dw_pcie_ep_init() method,
which will be taken should any consequent erroneous situation happens.

Fixes: 2fd0c9d966cc ("PCI: designware-ep: Pre-allocate memory for MSI in dw_pcie_ep_init")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

---

Changelog v2:
- This is a new patch create as a result of the discussion in:
  Link: https://lore.kernel.org/linux-pci/20220324014836.19149-26-Sergey.Semin@baikalelectronics.ru
---
 .../pci/controller/dwc/pcie-designware-ep.c    | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 0eda8236c125..13c2e73f0eaf 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -780,8 +780,9 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys,
 					     epc->mem->window.page_size);
 	if (!ep->msi_mem) {
+		ret = -ENOMEM;
 		dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
-		return -ENOMEM;
+		goto err_exit_epc_mem;
 	}
 
 	if (ep->ops->get_features) {
@@ -790,6 +791,19 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 			return 0;
 	}
 
-	return dw_pcie_ep_init_complete(ep);
+	ret = dw_pcie_ep_init_complete(ep);
+	if (ret)
+		goto err_free_epc_mem;
+
+	return 0;
+
+err_free_epc_mem:
+	pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
+			      epc->mem->window.page_size);
+
+err_exit_epc_mem:
+	pci_epc_mem_exit(epc);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_ep_init);
-- 
2.35.1