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Subject[RESEND PATCH v3 1/2] mm: Introducing arch_remap hook
Date
Some architecture would like to be triggered when a memory area is moved
through the mremap system call.

This patch is introducing a new arch_remap mm hook which is placed in the
path of mremap, and is called before the old area is unmapped (and the
arch_unmap hook is called).

The architectures which need to call this hook should define
__HAVE_ARCH_REMAP in their asm/mmu_context.h and provide the arch_remap
service with the following prototype:
void arch_remap(struct mm_struct *mm,
unsigned long old_start, unsigned long old_end,
unsigned long new_start, unsigned long new_end);

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
---
mm/mremap.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 2dc44b1cb1df..009db5565893 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -25,6 +25,7 @@

#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>

#include "internal.h"

@@ -286,13 +287,19 @@ static unsigned long move_vma(struct vm_area_struct *vma,
old_len = new_len;
old_addr = new_addr;
new_addr = -ENOMEM;
- } else if (vma->vm_file && vma->vm_file->f_op->mremap) {
- err = vma->vm_file->f_op->mremap(vma->vm_file, new_vma);
- if (err < 0) {
- move_page_tables(new_vma, new_addr, vma, old_addr,
- moved_len, true);
- return err;
+ } else {
+ if (vma->vm_file && vma->vm_file->f_op->mremap) {
+ err = vma->vm_file->f_op->mremap(vma->vm_file, new_vma);
+ if (err < 0) {
+ move_page_tables(new_vma, new_addr, vma,
+ old_addr, moved_len, true);
+ return err;
+ }
}
+#ifdef __HAVE_ARCH_REMAP
+ arch_remap(mm, old_addr, old_addr+old_len,
+ new_addr, new_addr+new_len);
+#endif
}

/* Conceal VM_ACCOUNT so old reservation is not undone */
--
1.9.1


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