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Date: Tue, 8 Mar 2011 19:42:19 -0500 From: Stephen Wilson <wilsons@...rt.ca> To: linux-mm@...ck.org Cc: Andrew Morton <akpm@...ux-foundation.org>, Alexander Viro <viro@...iv.linux.org.uk>, Rik van Riel <riel@...hat.com>, KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>, Roland McGrath <roland@...hat.com>, Matt Mackall <mpm@...enic.com>, David Rientjes <rientjes@...gle.com>, Nick Piggin <npiggin@...nel.dk>, Andrea Arcangeli <aarcange@...hat.com>, Mel Gorman <mel@....ul.ie>, Ingo Molnar <mingo@...e.hu>, Michel Lespinasse <walken@...gle.com>, Hugh Dickins <hughd@...gle.com>, linux-kernel@...r.kernel.org, Stephen Wilson <wilsons@...rt.ca> Subject: [PATCH 2/6] mm: factor out main logic of access_process_vm Introduce an internal helper __access_remote_vm and base access_process_vm on top of it. This new method may be called with a NULL task_struct if page fault accounting is not desired. This code will be shared with a new address space accessor that is independent of task_struct. Signed-off-by: Stephen Wilson <wilsons@...rt.ca> --- mm/memory.c | 35 +++++++++++++++++++++++++---------- 1 files changed, 25 insertions(+), 10 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 36445e3..68eec4f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3593,20 +3593,15 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, #endif /* - * Access another process' address space. - * Source/target buffer must be kernel space, - * Do not walk the page table directly, use get_user_pages + * Access another process' address space as given in mm. If non-NULL, use the + * given task for page fault accounting. */ -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 mm_struct *mm; struct vm_area_struct *vma; void *old_buf = buf; - mm = get_task_mm(tsk); - if (!mm) - return 0; - down_read(&mm->mmap_sem); /* ignore errors, just check how much was successfully transferred */ while (len) { @@ -3655,12 +3650,32 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in addr += bytes; } up_read(&mm->mmap_sem); - mmput(mm); return buf - old_buf; } /* + * Access another process' address space. + * Source/target buffer must be kernel space, + * Do not walk the page table directly, use get_user_pages + */ +int access_process_vm(struct task_struct *tsk, unsigned long addr, + void *buf, int len, int write) +{ + struct mm_struct *mm; + int ret; + + mm = get_task_mm(tsk); + if (!mm) + return 0; + + ret = __access_remote_vm(tsk, mm, addr, buf, len, write); + mmput(mm); + + return ret; +} + +/* * Print the name of a VMA. */ void print_vma_addr(char *prefix, unsigned long ip) -- 1.7.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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