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Commit 268364a0 authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

IO resources: add reserve_region_with_split() 



add reserve_region_with_split() to not lose e820 reserved entries if
they overlap with existing IO regions:

with test case by extend 0xe0000000 - 0xeffffff to 0xdd800000 -
we get:
	e0000000-efffffff : PCI MMCONFIG 0
		 e0000000-efffffff : reserved

and in /proc/iomem we get:
	found conflict for reserved [dd800000, efffffff], try to reserve with split
	    __reserve_region_with_split: (PCI Bus #80) [dd000000, ddffffff], res: (reserved) [dd800000, efffffff]
	    __reserve_region_with_split: (PCI Bus #00) [de000000, dfffffff], res: (reserved) [de000000, efffffff]
	initcall pci_subsys_init+0x0/0x121 returned 0 after 381 msecs
in dmesg

various fixes and improvements suggested by Linus.

Signed-off-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d210baf5

include/linux/ioport.h

+3 −0
Original line number Diff line number Diff line
@@ -108,6 +108,9 @@ extern struct resource iomem_resource; 


extern int request_resource(struct resource *root, struct resource *new);

extern int release_resource(struct resource *new);

extern void reserve_region_with_split(struct resource *root,

			     resource_size_t start, resource_size_t end,

			     const char *name);

extern int insert_resource(struct resource *parent, struct resource *new);

extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new);

extern int allocate_resource(struct resource *root, struct resource *new,

kernel/resource.c

+68 −0
Original line number Diff line number Diff line
@@ -516,6 +516,74 @@ int adjust_resource(struct resource *res, resource_size_t start, resource_size_t 
	return result;

}



static void __init __reserve_region_with_split(struct resource *root,

		resource_size_t start, resource_size_t end,

		const char *name)

{

	struct resource *parent = root;

	struct resource *conflict;

	struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);



	if (!res)

		return;



	res->name = name;

	res->start = start;

	res->end = end;

	res->flags = IORESOURCE_BUSY;



	for (;;) {

		conflict = __request_resource(parent, res);

		if (!conflict)

			break;

		if (conflict != parent) {

			parent = conflict;

			if (!(conflict->flags & IORESOURCE_BUSY))

				continue;

		}



		/* Uhhuh, that didn't work out.. */

		kfree(res);

		res = NULL;

		break;

	}



	if (!res) {

		printk(KERN_DEBUG "    __reserve_region_with_split: (%s) [%llx, %llx], res: (%s) [%llx, %llx]\n",

			 conflict->name, conflict->start, conflict->end,

			 name, start, end);



		/* failed, split and try again */



		/* conflict coverred whole area */

		if (conflict->start <= start && conflict->end >= end)

			return;



		if (conflict->start > start)

			__reserve_region_with_split(root, start, conflict->start-1, name);

		if (!(conflict->flags & IORESOURCE_BUSY)) {

			resource_size_t common_start, common_end;



			common_start = max(conflict->start, start);

			common_end = min(conflict->end, end);

			if (common_start < common_end)

				__reserve_region_with_split(root, common_start, common_end, name);

		}

		if (conflict->end < end)

			__reserve_region_with_split(root, conflict->end+1, end, name);

	}



}



void reserve_region_with_split(struct resource *root,

		resource_size_t start, resource_size_t end,

		const char *name)

{

	write_lock(&resource_lock);

	__reserve_region_with_split(root, start, end, name);

	write_unlock(&resource_lock);

}



EXPORT_SYMBOL(adjust_resource);



/**