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2039e6acaf
Using mremap() to shrink the map size of a VM_PFNMAP range causes the following error message, and leaves the pfn range allocated. x86/PAT: test:3493 freeing invalid memtype [mem 0x483200000-0x4863fffff] This is because rbt_memtype_erase(), called from free_memtype() with spin_lock held, only supports to free a whole memtype node in memtype_rbroot. Therefore, this patch changes rbt_memtype_erase() to support a request that shrinks the size of a memtype node for mremap(). memtype_rb_exact_match() is renamed to memtype_rb_match(), and is enhanced to support EXACT_MATCH and END_MATCH in @match_type. Since the memtype_rbroot tree allows overlapping ranges, rbt_memtype_erase() checks with EXACT_MATCH first, i.e. free a whole node for the munmap case. If no such entry is found, it then checks with END_MATCH, i.e. shrink the size of a node from the end for the mremap case. On the mremap case, rbt_memtype_erase() proceeds in two steps, 1) remove the node, and then 2) insert the updated node. This allows proper update of augmented values, subtree_max_end, in the tree. Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Borislav Petkov <bp@suse.de> Cc: stsp@list.ru Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/1450832064-10093-3-git-send-email-toshi.kani@hpe.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>