PCI: Push realloc check into pbus_size_mem()

pbus_size_mem() and calculate_memsize() input both min_size and add_size.
They are given the same value if realloc_head is NULL and min_size is 0
otherwise. Both are used in calculate_memsize() to enforce a lower bound to
the size.

The interface between __pci_bus_size_bridges() and the forementioned
functions can be simplied by pushing the realloc check into
pbus_size_mem().

There are only two possible cases:

  1) when calculating size0, add_size parameter given to
     calculate_memsize() is always 0 which implies only min_size
     matters.

  2) when calculating size1, realloc_head is not NULL which implies
     min_size=0 so only add_size matters.

Drop min_size parameter from pbus_size_mem() and check realloc_head when
calling calculate_memsize(). Drop add_size from calculate_memsize() and use
only min_size within max() to enforce the lower bound.

calculate_iosize() is a bit more complicated than calculate_memsize() and
is therefore left as is, but pbus_size_io() can still input only min_size
similar to pbus_size_mem().

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20251219174036.16738-7-ilpo.jarvinen@linux.intel.com

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 8660449f59bd568ccda0a6cc17a244c59b4061f4..f85ae20dc8946cc69d03afee24a8e8225cc0d352 100644 (file)
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1069,14 +1069,10 @@ static resource_size_t calculate_iosize(resource_size_t size,
 
 static resource_size_t calculate_memsize(resource_size_t size,
                                         resource_size_t min_size,
-                                        resource_size_t add_size,
                                         resource_size_t children_add_size,
                                         resource_size_t align)
 {
-       if (size < min_size)
-               size = min_size;
-
-       size = max(size, add_size) + children_add_size;
+       size = max(size, min_size) + children_add_size;
        return ALIGN(size, align);
 }
 
@@ -1115,8 +1111,7 @@ static resource_size_t window_alignment(struct pci_bus *bus, unsigned long type)
  * pbus_size_io() - Size the I/O window of a given bus
  *
  * @bus:               The bus
- * @min_size:          The minimum I/O window that must be allocated
- * @add_size:          Additional optional I/O window
+ * @add_size:          Additional I/O window
  * @realloc_head:      Track the additional I/O window on this list
  *
  * Sizing the I/O windows of the PCI-PCI bridge is trivial, since these
@@ -1124,8 +1119,7 @@ static resource_size_t window_alignment(struct pci_bus *bus, unsigned long type)
  * devices are limited to 256 bytes.  We must be careful with the ISA
  * aliasing though.
  */
-static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
-                        resource_size_t add_size,
+static void pbus_size_io(struct pci_bus *bus, resource_size_t add_size,
                         struct list_head *realloc_head)
 {
        struct pci_dev *dev;
@@ -1170,7 +1164,7 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
                }
        }
 
-       size0 = calculate_iosize(size, min_size, size1, 0, 0,
+       size0 = calculate_iosize(size, realloc_head ? 0 : add_size, size1, 0, 0,
                        resource_size(b_res), min_align);
 
        if (size0)
@@ -1178,7 +1172,7 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
 
        size1 = size0;
        if (realloc_head && (add_size > 0 || children_add_size > 0)) {
-               size1 = calculate_iosize(size, min_size, size1, add_size,
+               size1 = calculate_iosize(size, 0, size1, add_size,
                                         children_add_size, resource_size(b_res),
                                         min_align);
        }
@@ -1269,8 +1263,7 @@ static resource_size_t calculate_head_align(resource_size_t *aligns,
  *
  * @bus:               The bus
  * @type:              The type of bridge resource
- * @min_size:          The minimum memory window that must be allocated
- * @add_size:          Additional optional memory window
+ * @add_size:          Additional memory window
  * @realloc_head:      Track the additional memory window on this list
  *
  * Calculate the size of the bus resource for @type and minimal alignment
@@ -1283,7 +1276,6 @@ static resource_size_t calculate_head_align(resource_size_t *aligns,
  * supplied.
  */
 static void pbus_size_mem(struct pci_bus *bus, unsigned long type,
-                        resource_size_t min_size,
                         resource_size_t add_size,
                         struct list_head *realloc_head)
 {
@@ -1363,7 +1355,8 @@ static void pbus_size_mem(struct pci_bus *bus, unsigned long type,
        win_align = window_alignment(bus, b_res->flags);
        min_align = calculate_head_align(aligns, max_order);
        min_align = max(min_align, win_align);
-       size0 = calculate_memsize(size, min_size, 0, 0, win_align);
+       size0 = calculate_memsize(size, realloc_head ? 0 : add_size,
+                                 0, win_align);
 
        if (size0) {
                resource_set_range(b_res, min_align, size0);
@@ -1372,7 +1365,7 @@ static void pbus_size_mem(struct pci_bus *bus, unsigned long type,
 
        if (realloc_head && (add_size > 0 || children_add_size > 0)) {
                add_align = max(min_align, add_align);
-               size1 = calculate_memsize(size, min_size, add_size, children_add_size,
+               size1 = calculate_memsize(size, add_size, children_add_size,
                                          win_align);
        }
 
@@ -1550,20 +1543,17 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
                }
                fallthrough;
        default:
-               pbus_size_io(bus, realloc_head ? 0 : additional_io_size,
-                            additional_io_size, realloc_head);
+               pbus_size_io(bus, additional_io_size, realloc_head);
 
                if (pref && (pref->flags & IORESOURCE_PREFETCH)) {
                        pbus_size_mem(bus,
                                      IORESOURCE_MEM | IORESOURCE_PREFETCH |
                                      (pref->flags & IORESOURCE_MEM_64),
-                                     realloc_head ? 0 : additional_mmio_pref_size,
                                      additional_mmio_pref_size, realloc_head);
                }
 
-               pbus_size_mem(bus, IORESOURCE_MEM,
-                             realloc_head ? 0 : additional_mmio_size,
-                             additional_mmio_size, realloc_head);
+               pbus_size_mem(bus, IORESOURCE_MEM, additional_mmio_size,
+                             realloc_head);
                break;
        }
 }