From e4a5b2f60e0697ad6f4844a76b142764cad3d745 Mon Sep 17 00:00:00 2001 From: Alison Schofield Date: Mon, 13 Nov 2023 14:13:24 -0800 Subject: [PATCH] kernel/resource: Increment by align value in get_free_mem_region() [ Upstream commit 659aa050a53817157b7459529538598a6449c1d3 ] 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. Specifically 'cxl create-region' fails with ERANGE even though capacity of the given size and CXL's expected 256M x InterleaveWays alignment can be satisfied. Replace the total-request-size increment with a next 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 Reported-by: Dan Williams Signed-off-by: Alison Schofield Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/20231113221324.1118092-1-alison.schofield@intel.com Cc: Jason Gunthorpe Reviewed-by: Christoph Hellwig Signed-off-by: Dan Williams Signed-off-by: Sasha Levin --- kernel/resource.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/resource.c b/kernel/resource.c index b1763b2fd7ef..e3f5680a564c 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -1847,8 +1847,8 @@ 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;