firewire: ohci: release buffer for AR req/resp contexts when managed resource is released

The 1394 OHCI driver allocates several non-coherent DMA buffers for AR
request and response contexts. The buffers are mapped to kernel virtual
address (VMA) so that the first page locates after the last page. Even
when large payload of packet is handled crossing the boundary of buffers,
the driver operates continuously on VMA.

No kernel API is provided for this kind of mapping, while it is possible
to release the buffer when PCI device is going to be released.

This commit moves the call of release helper function to the callback
function of release resources.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Sakamoto <[e-mail]>

drivers/firewire/ohci.c

···
 	struct device *dev = ctx->ohci->card.device;
 	unsigned int i;
 
+	if (!ctx->buffer)
+		return;
+
 	vunmap(ctx->buffer);
 
 	for (i = 0; i < AR_BUFFERS; i++) {
···
 static void release_ohci(struct device *dev, void *data)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
+	struct fw_ohci *ohci = pci_get_drvdata(pdev);
 
 	pmac_ohci_off(pdev);
+
+	ar_context_release(&ohci->ar_response_ctx);
+	ar_context_release(&ohci->ar_request_ctx);
 
 	dev_notice(dev, "removed fw-ohci device\n");
 }
···
 	err = ar_context_init(&ohci->ar_response_ctx, ohci, PAGE_SIZE/4,
 			      OHCI1394_AsRspRcvContextControlSet);
 	if (err < 0)
-		goto fail_arreq_ctx;
+		return err;
 
 	err = context_init(&ohci->at_request_ctx, ohci,
 			   OHCI1394_AsReqTrContextControlSet, handle_at_packet);
 	if (err < 0)
-		goto fail_arrsp_ctx;
+		return err;
 
 	err = context_init(&ohci->at_response_ctx, ohci,
 			   OHCI1394_AsRspTrContextControlSet, handle_at_packet);
 	if (err < 0)
-		goto fail_arrsp_ctx;
+		return err;
 
 	reg_write(ohci, OHCI1394_IsoRecvIntMaskSet, ~0);
 	ohci->ir_context_channels = ~0ULL;
···
 	ohci->n_ir = hweight32(ohci->ir_context_mask);
 	size = sizeof(struct iso_context) * ohci->n_ir;
 	ohci->ir_context_list = devm_kzalloc(&dev->dev, size, GFP_KERNEL);
-	if (!ohci->ir_context_list) {
-		err = -ENOMEM;
-		goto fail_arrsp_ctx;
-	}
+	if (!ohci->ir_context_list)
+		return -ENOMEM;
 
 	reg_write(ohci, OHCI1394_IsoXmitIntMaskSet, ~0);
 	ohci->it_context_support = reg_read(ohci, OHCI1394_IsoXmitIntMaskSet);
···
 	ohci->n_it = hweight32(ohci->it_context_mask);
 	size = sizeof(struct iso_context) * ohci->n_it;
 	ohci->it_context_list = devm_kzalloc(&dev->dev, size, GFP_KERNEL);
-	if (!ohci->it_context_list) {
-		err = -ENOMEM;
-		goto fail_arrsp_ctx;
-	}
+	if (!ohci->it_context_list)
+		return -ENOMEM;
 
 	ohci->self_id     = ohci->misc_buffer     + PAGE_SIZE/2;
 	ohci->self_id_bus = ohci->misc_buffer_bus + PAGE_SIZE/2;
···
 
  fail_msi:
 	pci_disable_msi(dev);
- fail_arrsp_ctx:
-	ar_context_release(&ohci->ar_response_ctx);
- fail_arreq_ctx:
-	ar_context_release(&ohci->ar_request_ctx);
 
 	return err;
 }
···
 
 	software_reset(ohci);
 
-	ar_context_release(&ohci->ar_request_ctx);
-	ar_context_release(&ohci->ar_response_ctx);
 	pci_disable_msi(dev);
 
 	dev_notice(&dev->dev, "removing fw-ohci device\n");