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SubjectRe: [RESEND PATCH v3 1/2] mm: Introducing arch_remap hook
On Mon, Apr 13, 2015 at 11:56:27AM +0200, Laurent Dufour wrote:
> 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

It would be cleaner to provide dummy arch_remap() for !__HAVE_ARCH_REMAP
in some generic header.


> + arch_remap(mm, old_addr, old_addr+old_len,
> + new_addr, new_addr+new_len);

Spaces around '+'?

> +#endif
> }
>
> /* Conceal VM_ACCOUNT so old reservation is not undone */
> --
> 1.9.1
>
> --
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--
Kirill A. Shutemov


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