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| author | Stephen Wilson <wilsons@start.ca> | 2011-03-13 15:49:19 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2011-03-23 16:36:56 -0400 |
| commit | 206cb636576b969e9b471cdedeaea7752e6acb33 (patch) | |
| tree | 252a1b5e9ce41521fb93b519265d4a1dbd18cfe9 /mm/memory.c | |
| parent | e7f22e207bacdba5b73f2893a3abe935a5373e2e (diff) | |
| download | kernel-common-206cb636576b969e9b471cdedeaea7752e6acb33.tar.gz kernel-common-206cb636576b969e9b471cdedeaea7752e6acb33.tar.bz2 kernel-common-206cb636576b969e9b471cdedeaea7752e6acb33.zip | |
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@start.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/mm/memory.c b/mm/memory.c index 5f585b65d734..820b4c4810f0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3650,20 +3650,15 @@ 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) { @@ -3712,12 +3707,32 @@ 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) |