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Commit 9943242c authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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mremap: simplify the "overlap" check in mremap_to() 



Minor, but this check is overcomplicated.  Two half-intervals do NOT
overlap if END1 <= START2 || END2 <= START1, mremap_to() just needs to
negate this check.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1d391686

mm/mremap.c

+2 −7
Original line number Diff line number Diff line
@@ -407,13 +407,8 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len, 
	if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)

		goto out;



	/* Check if the location we're moving into overlaps the

	 * old location at all, and fail if it does.

	 */

	if ((new_addr <= addr) && (new_addr+new_len) > addr)

		goto out;



	if ((addr <= new_addr) && (addr+old_len) > new_addr)

	/* Ensure the old/new locations do not overlap */

	if (addr + old_len > new_addr && new_addr + new_len > addr)

		goto out;



	ret = do_munmap(mm, new_addr, new_len);