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SubjectRe: [PATCH] NOMMU: implement access_remote_vm
On 26/03/11 06:32, Mike Frysinger wrote:
> Recent vm changes brought in a new function which the core procfs code
> utilizes. So implement it for nommu systems too to avoid link failures.
>
> Signed-off-by: Mike Frysinger<vapier@gentoo.org>

Looks good.

Acked-by: Greg Ungerer <gerg@uclinux.org>


> ---
> mm/nommu.c | 52 +++++++++++++++++++++++++++++++++++++++-------------
> 1 files changed, 39 insertions(+), 13 deletions(-)
>
> diff --git a/mm/nommu.c b/mm/nommu.c
> index cb86e7d..c4c542c 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -1971,21 +1971,10 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> }
> EXPORT_SYMBOL(filemap_fault);
>
> -/*
> - * Access another process' address space.
> - * - source/target buffer must be kernel space
> - */
> -int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
> +static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
> + unsigned long addr, void *buf, int len, int write)
> {
> struct vm_area_struct *vma;
> - struct mm_struct *mm;
> -
> - if (addr + len< addr)
> - return 0;
> -
> - mm = get_task_mm(tsk);
> - if (!mm)
> - return 0;
>
> down_read(&mm->mmap_sem);
>
> @@ -2010,6 +1999,43 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
> }
>
> up_read(&mm->mmap_sem);
> +
> + return len;
> +}
> +
> +/**
> + * @access_remote_vm - access another process' address space
> + * @mm: the mm_struct of the target address space
> + * @addr: start address to access
> + * @buf: source or destination buffer
> + * @len: number of bytes to transfer
> + * @write: whether the access is a write
> + *
> + * The caller must hold a reference on @mm.
> + */
> +int access_remote_vm(struct mm_struct *mm, unsigned long addr,
> + void *buf, int len, int write)
> +{
> + return __access_remote_vm(NULL, mm, addr, buf, len, write);
> +}
> +
> +/*
> + * Access another process' address space.
> + * - source/target buffer must be kernel space
> + */
> +int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
> +{
> + struct mm_struct *mm;
> +
> + if (addr + len< addr)
> + return 0;
> +
> + mm = get_task_mm(tsk);
> + if (!mm)
> + return 0;
> +
> + len = __access_remote_vm(tsk, mm, addr, buf, len, write);
> +
> mmput(mm);
> return len;
> }


--
------------------------------------------------------------------------
Greg Ungerer -- Principal Engineer EMAIL: gerg@snapgear.com
SnapGear Group, McAfee PHONE: +61 7 3435 2888
8 Gardner Close FAX: +61 7 3217 5323
Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com


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