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

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: 14b80582c4 ("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>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20231113221324.1118092-1-alison.schofield@intel.com
Cc: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Alison Schofield 2023-11-13 14:13:24 -08:00 committed by Dan Williams
parent e05501e8a8
commit 659aa050a5
1 changed files with 2 additions and 2 deletions
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4
kernel/resource.c
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@ -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;