Many callers of pci_rebar_get_possible_sizes() are interested in finding
out if a particular encoded BAR Size (PCIe r7.0, sec 7.8.6.3) is supported
by the particular BAR.

Add pci_rebar_size_supported() into PCI core to make it easy for the
drivers to determine if the BAR size is supported or not.

Use the new function in pci_resize_resource() and in
pci_iov_vf_bar_set_size().

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
---
 drivers/pci/iov.c   |  8 +-------
 drivers/pci/rebar.c | 25 +++++++++++++++++++------
 include/linux/pci.h |  1 +
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 04b675e90963..71ed85d38508 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -1339,19 +1339,13 @@ EXPORT_SYMBOL_GPL(pci_sriov_configure_simple);
  */
 int pci_iov_vf_bar_set_size(struct pci_dev *dev, int resno, int size)
 {
-	u32 sizes;
-
 	if (!pci_resource_is_iov(resno))
 		return -EINVAL;
 
 	if (pci_iov_is_memory_decoding_enabled(dev))
 		return -EBUSY;
 
-	sizes = pci_rebar_get_possible_sizes(dev, resno);
-	if (!sizes)
-		return -ENOTSUPP;
-
-	if (!(sizes & BIT(size)))
+	if (!pci_rebar_size_supported(dev, resno, size))
 		return -EINVAL;
 
 	return pci_rebar_set_size(dev, resno, size);
diff --git a/drivers/pci/rebar.c b/drivers/pci/rebar.c
index e5c0ea6d6063..0e7bf2d380cf 100644
--- a/drivers/pci/rebar.c
+++ b/drivers/pci/rebar.c
@@ -3,6 +3,7 @@
  * PCI Resizable BAR Extended Capability handling.
  */
 
+#include <linux/bits.h>
 #include <linux/bitfield.h>
 #include <linux/errno.h>
 #include <linux/export.h>
@@ -124,6 +125,23 @@ u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar)
 }
 EXPORT_SYMBOL(pci_rebar_get_possible_sizes);
 
+/**
+ * pci_rebar_size_supported - check if size is supported for BAR
+ * @pdev: PCI device
+ * @bar: BAR to check
+ * @size: size as defined in the PCIe spec (0=1MB, 31=128TB)
+ *
+ * Return: %true if @bar is resizable and @size is a supported, otherwise
+ *	   %false.
+ */
+bool pci_rebar_size_supported(struct pci_dev *pdev, int bar, int size)
+{
+	u64 sizes = pci_rebar_get_possible_sizes(pdev, bar);
+
+	return BIT(size) & sizes;
+}
+EXPORT_SYMBOL_GPL(pci_rebar_size_supported);
+
 /**
  * pci_rebar_get_current_size - get the current size of a Resizable BAR
  * @pdev: PCI device
@@ -252,7 +270,6 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size,
 {
 	struct pci_host_bridge *host;
 	int old, ret;
-	u32 sizes;
 
 	/* Check if we must preserve the firmware's resource assignment */
 	host = pci_find_host_bridge(dev->bus);
@@ -262,11 +279,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size,
 	if (pci_resize_is_memory_decoding_enabled(dev, resno))
 		return -EBUSY;
 
-	sizes = pci_rebar_get_possible_sizes(dev, resno);
-	if (!sizes)
-		return -ENOTSUPP;
-
-	if (!(sizes & BIT(size)))
+	if (!pci_rebar_size_supported(dev, resno, size))
 		return -EINVAL;
 
 	old = pci_rebar_get_current_size(dev, resno);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 33b27e0c4f3e..0ef827cfaf0c 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1424,6 +1424,7 @@ int pci_release_resource(struct pci_dev *dev, int resno);
 int pci_rebar_bytes_to_size(u64 bytes);
 resource_size_t pci_rebar_size_to_bytes(int size);
 u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar);
+bool pci_rebar_size_supported(struct pci_dev *pdev, int bar, int size);
 int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size,
 				     int exclude_bars);
 
-- 
2.39.5