PCI: Remove legacy pcim_release()

Thanks to preceding cleanup steps, pcim_release() is now not needed
anymore and can be replaced by pcim_disable_device(), which is the exact
counterpart to pcim_enable_device().

This permits removing further parts of the old PCI devres implementation.

Replace pcim_release() with pcim_disable_device().  Remove the now unused
function get_pci_dr().  Remove the struct pci_devres from pci.h.

Link: https://lore.kernel.org/r/20240613115032.29098-12-pstanner@redhat.com
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Author: Philipp Stanner

drivers/pci/devres.c

@@ -477,48 +477,45 @@ int pcim_intx(struct pci_dev *pdev, int enable)
 	return 0;
 }
 
-static void pcim_release(struct device *gendev, void *res)
+static void pcim_disable_device(void *pdev_raw)
 {
-	struct pci_dev *dev = to_pci_dev(gendev);
-
-	if (pci_is_enabled(dev) && !dev->pinned)
-		pci_disable_device(dev);
-}
-
-static struct pci_devres *get_pci_dr(struct pci_dev *pdev)
-{
-	struct pci_devres *dr, *new_dr;
-
-	dr = devres_find(&pdev->dev, pcim_release, NULL, NULL);
-	if (dr)
-		return dr;
+	struct pci_dev *pdev = pdev_raw;
 
-	new_dr = devres_alloc(pcim_release, sizeof(*new_dr), GFP_KERNEL);
-	if (!new_dr)
-		return NULL;
-	return devres_get(&pdev->dev, new_dr, NULL, NULL);
+	if (!pdev->pinned)
+		pci_disable_device(pdev);
 }
 
 /**
  * pcim_enable_device - Managed pci_enable_device()
  * @pdev: PCI device to be initialized
  *
- * Managed pci_enable_device().
+ * Returns: 0 on success, negative error code on failure.
+ *
+ * Managed pci_enable_device(). Device will automatically be disabled on
+ * driver detach.
  */
 int pcim_enable_device(struct pci_dev *pdev)
 {
-	struct pci_devres *dr;
-	int rc;
+	int ret;
 
-	dr = get_pci_dr(pdev);
-	if (unlikely(!dr))
-		return -ENOMEM;
+	ret = devm_add_action(&pdev->dev, pcim_disable_device, pdev);
+	if (ret != 0)
+		return ret;
 
-	rc = pci_enable_device(pdev);
-	if (!rc)
-		pdev->is_managed = 1;
+	/*
+	 * We prefer removing the action in case of an error over
+	 * devm_add_action_or_reset() because the latter could theoretically be
+	 * disturbed by users having pinned the device too soon.
+	 */
+	ret = pci_enable_device(pdev);
+	if (ret != 0) {
+		devm_remove_action(&pdev->dev, pcim_disable_device, pdev);
+		return ret;
+	}
 
-	return rc;
+	pdev->is_managed = true;
+
+	return ret;
 }
 EXPORT_SYMBOL(pcim_enable_device);
 

drivers/pci/pci.h

@@ -810,22 +810,6 @@ static inline pci_power_t mid_pci_get_power_state(struct pci_dev *pdev)
 }
 #endif
 
-/*
- * Managed PCI resources.  This manages device on/off, INTx/MSI/MSI-X
- * on/off and BAR regions.  pci_dev itself records MSI/MSI-X status, so
- * there's no need to track it separately.  pci_devres is initialized
- * when a device is enabled using managed PCI device enable interface.
- *
- * TODO: Struct pci_devres only needs to be here because they're used in pci.c.
- * Port or move these functions to devres.c and then remove them from here.
- */
-struct pci_devres {
-	/*
-	 * TODO:
-	 * This struct is now surplus. Remove it by refactoring pci/devres.c
-	 */
-};
-
 int pcim_intx(struct pci_dev *dev, int enable);
 
 int pcim_request_region(struct pci_dev *pdev, int bar, const char *name);