[PATCH] kernel/resource: Increment by align value in get_free_mem_region()

[alison.schofield@intel.com]

From: Alison Schofield <alison.schofield@intel.com>

Currently get_free_mem_region() searches for available capacity
in increments equal to the region size being requested. This can
cause the search to take giant steps through the resource leaving
needless gaps and missing available space.

Replace the size increment with an alignment increment so that the
next possible address is always examined for availability.

Fixes: 14b80582c43e ("resource: Introduce alloc_free_mem_region()")
Reported-by: Dmytro Adamenko <dmytro.adamenko@intel.com>
Reported-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---

A couple of below the line items:

The MAINTAINERS file and get_maintainers script did not emit a clear
recipient list for this one. Start with CXL folks and I can expand
it in a v2 with your help.

I considered, but didn't, change the parameter naming in gfr_continue(),
gfr_next(). It's a choice as get_free_mem_region() is the only caller.
Thoughts?


 kernel/resource.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 866ef3663a0b..91be1bc50b60 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1844,8 +1844,8 @@ get_free_mem_region(struct device *dev, struct resource *base,
 
 	write_lock(&resource_lock);
 	for (addr = gfr_start(base, size, align, flags);
-	     gfr_continue(base, addr, size, flags);
-	     addr = gfr_next(addr, size, flags)) {
+	     gfr_continue(base, addr, align, flags);
+	     addr = gfr_next(addr, align, flags)) {
 		if (__region_intersects(base, addr, size, 0, IORES_DESC_NONE) !=
 		    REGION_DISJOINT)
 			continue;

base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86
-- 
2.37.3