From 14b80582c43e4f550acfd93c2b2cadbe36ea0874 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 20 May 2022 13:41:24 -0700 Subject: resource: Introduce alloc_free_mem_region() The core of devm_request_free_mem_region() is a helper that searches for free space in iomem_resource and performs __request_region_locked() on the result of that search. The policy choices of the implementation conform to what CONFIG_DEVICE_PRIVATE users want which is memory that is immediately marked busy, and a preference to search for the first-fit free range in descending order from the top of the physical address space. CXL has a need for a similar allocator, but with the following tweaks: 1/ Search for free space in ascending order 2/ Search for free space relative to a given CXL window 3/ 'insert' rather than 'request' the new resource given downstream drivers from the CXL Region driver (like the pmem or dax drivers) are responsible for request_mem_region() when they activate the memory range. Rework __request_free_mem_region() into get_free_mem_region() which takes a set of GFR_* (Get Free Region) flags to control the allocation policy (ascending vs descending), and "busy" policy (insert_resource() vs request_region()). As part of the consolidation of the legacy GFR_REQUEST_REGION case with the new default of just inserting a new resource into the free space some minor cleanups like not checking for NULL before calling devres_free() (which does its own check) is included. Suggested-by: Jason Gunthorpe Link: https://lore.kernel.org/linux-cxl/20220420143406.GY2120790@nvidia.com/ Cc: Matthew Wilcox Cc: Christoph Hellwig Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/165784333333.1758207.13703329337805274043.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams --- include/linux/ioport.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 79d1ad6d6275..616b683563a9 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -330,6 +330,8 @@ struct resource *devm_request_free_mem_region(struct device *dev, struct resource *base, unsigned long size); struct resource *request_free_mem_region(struct resource *base, unsigned long size, const char *name); +struct resource *alloc_free_mem_region(struct resource *base, + unsigned long size, unsigned long align, const char *name); static inline void irqresource_disabled(struct resource *res, u32 irq) { -- cgit v1.2.3