PCI: Add and use devres helper for bit masks

The current devres implementation uses manual shift operations to check
whether a bit in a mask is set. The code can be made more readable by
writing a small helper function for that.

Implement mask_contains_bar() and use it where applicable.

Link: https://lore.kernel.org/r/20240613115032.29098-2-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>

drivers/pci/devres.c

@@ -161,6 +161,10 @@ int pcim_set_mwi(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pcim_set_mwi);
 
+static inline bool mask_contains_bar(int mask, int bar)
+{
+	return mask & BIT(bar);
+}
 
 static void pcim_release(struct device *gendev, void *res)
 {
@@ -169,7 +173,7 @@ static void pcim_release(struct device *gendev, void *res)
 	int i;
 
 	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
-		if (this->region_mask & (1 << i))
+		if (mask_contains_bar(this->region_mask, i))
 			pci_release_region(dev, i);
 
 	if (this->mwi)
@@ -363,7 +367,7 @@ int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name)
 	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
 		unsigned long len;
 
-		if (!(mask & (1 << i)))
+		if (!mask_contains_bar(mask, i))
 			continue;
 
 		rc = -EINVAL;
@@ -386,7 +390,7 @@ int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name)
 	pci_release_region(pdev, i);
  err_inval:
 	while (--i >= 0) {
-		if (!(mask & (1 << i)))
+		if (!mask_contains_bar(mask, i))
 			continue;
 		pcim_iounmap(pdev, iomap[i]);
 		pci_release_region(pdev, i);
@@ -438,7 +442,7 @@ void pcim_iounmap_regions(struct pci_dev *pdev, int mask)
 		return;
 
 	for (i = 0; i < PCIM_IOMAP_MAX; i++) {
-		if (!(mask & (1 << i)))
+		if (!mask_contains_bar(mask, i))
 			continue;
 
 		pcim_iounmap(pdev, iomap[i]);