resource: Handle simple alignment inside __find_resource_space()

allocate_resource() accepts ->alignf() callback to perform custom alignment
beyond constraint->align. If alignf is NULL, simple_align_resource() is
used which only returns avail->start (no change).

Using avail->start directly is natural and can be done with a conditional
in __find_resource_space() instead which avoids unnecessarily using
callback. It makes the code inside __find_resource_space() more obvious and
removes the need for the caller to provide constraint->alignf
unnecessarily.

This is preparation for exporting find_resource_space().

Link: https://lore.kernel.org/r/20240507102523.57320-6-ilpo.jarvinen@linux.intel.com
Tested-by: Lidong Wang <lidong.wang@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/kernel/resource.c b/kernel/resource.c
index 26ad6f223652aec5bd2c0c9d8dc5c4e0cecfd09e..35c44c23b03706ecc4fcceec5526aed7aa963680 100644 (file)
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -621,14 +621,6 @@ void __weak arch_remove_reservations(struct resource *avail)
 {
 }
 
-static resource_size_t simple_align_resource(void *data,
-                                            const struct resource *avail,
-                                            resource_size_t size,
-                                            resource_size_t align)
-{
-       return avail->start;
-}
-
 static void resource_clip(struct resource *res, resource_size_t min,
                          resource_size_t max)
 {
@@ -648,6 +640,7 @@ static int __find_resource_space(struct resource *root, struct resource *old,
 {
        struct resource *this = root->child;
        struct resource tmp = *new, avail, alloc;
+       resource_alignf alignf = constraint->alignf;
 
        tmp.start = root->start;
        /*
@@ -676,8 +669,12 @@ static int __find_resource_space(struct resource *root, struct resource *old,
                avail.flags = new->flags & ~IORESOURCE_UNSET;
                if (avail.start >= tmp.start) {
                        alloc.flags = avail.flags;
-                       alloc.start = constraint->alignf(constraint->alignf_data, &avail,
-                                       size, constraint->align);
+                       if (alignf) {
+                               alloc.start = alignf(constraint->alignf_data,
+                                                    &avail, size, constraint->align);
+                       } else {
+                               alloc.start = avail.start;
+                       }
                        alloc.end = alloc.start + size - 1;
                        if (alloc.start <= alloc.end &&
                            resource_contains(&avail, &alloc)) {
@@ -788,9 +785,6 @@ int allocate_resource(struct resource *root, struct resource *new,
        int err;
        struct resource_constraint constraint;
 
-       if (!alignf)
-               alignf = simple_align_resource;
-
        constraint.min = min;
        constraint.max = max;
        constraint.align = align;