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Commit 78a8b35b authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

x86: make e820_update_range() handle small range update 



Impact: enhance e820 code to handle more cases

Try to handle new range which could be covered by one entry.

Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Cc: jbeulich@novell.com
LKML-Reference: <49B9F0C1.10402@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 773e673d

arch/x86/kernel/e820.c

+19 −4
Original line number Diff line number Diff line
@@ -427,6 +427,7 @@ static u64 __init __e820_update_range(struct e820map *e820x, u64 start, 
					u64 size, unsigned old_type,

					unsigned new_type)

{

	u64 end;

	unsigned int i;

	u64 real_updated_size = 0;
@@ -435,21 +436,35 @@ static u64 __init __e820_update_range(struct e820map *e820x, u64 start, 
	if (size > (ULLONG_MAX - start))

		size = ULLONG_MAX - start;



	end = start + size;

	for (i = 0; i < e820x->nr_map; i++) {

		struct e820entry *ei = &e820x->map[i];

		u64 final_start, final_end;

		u64 ei_end;



		if (ei->type != old_type)

			continue;

		/* totally covered? */

		if (ei->addr >= start &&

		    (ei->addr + ei->size) <= (start + size)) {



		ei_end = ei->addr + ei->size;

		/* totally covered by new range? */

		if (ei->addr >= start && ei_end <= end) {

			ei->type = new_type;

			real_updated_size += ei->size;

			continue;

		}



		/* new range is totally covered? */

		if (ei->addr < start && ei_end > end) {

			__e820_add_region(e820x, start, size, new_type);

			__e820_add_region(e820x, end, ei_end - end, ei->type);

			ei->size = start - ei->addr;

			real_updated_size += size;

			continue;

		}



		/* partially covered */

		final_start = max(start, ei->addr);

		final_end = min(start + size, ei->addr + ei->size);

		final_end = min(end, ei_end);

		if (final_start >= final_end)

			continue;