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SubjectRe: [rfc 1/2] x86, bts, mm: buffer allocation
On Fri, 24 Apr 2009 09:51:43 +0200 Markus Metzger <markus.t.metzger@intel.com> wrote:

> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -629,38 +629,36 @@ void user_shm_unlock(size_t size, struct
> free_uid(user);
> }
>
> -void *alloc_locked_buffer(size_t size)
> +int account_locked_memory(struct mm_struct *mm, struct rlimit *rlim,
> + size_t size)
> {
> - unsigned long rlim, vm, pgsz;
> - void *buffer = NULL;
> + unsigned long lim, vm, pgsz;
> + int error = -ENOMEM;
>
> pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT;
>
> - down_write(&current->mm->mmap_sem);
> -
> - rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
> - vm = current->mm->total_vm + pgsz;
> - if (rlim < vm)
> - goto out;
> + down_write(&mm->mmap_sem);
>
> - rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
> - vm = current->mm->locked_vm + pgsz;
> - if (rlim < vm)
> + lim = rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
> + vm = mm->total_vm + pgsz;
> + if (lim < vm)
> goto out;
>
> - buffer = kzalloc(size, GFP_KERNEL);
> - if (!buffer)
> + lim = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
> + vm = mm->locked_vm + pgsz;
> + if (lim < vm)
> goto out;
>
> - current->mm->total_vm += pgsz;
> - current->mm->locked_vm += pgsz;
> + mm->total_vm += pgsz;
> + mm->locked_vm += pgsz;
>
> + error = 0;
> out:
> - up_write(&current->mm->mmap_sem);
> - return buffer;
> + up_write(&mm->mmap_sem);
> + return error;
> }

Looks OK to me. Getting that GFP_KERNEL allocation out from inside
mmap_sem can only be good.



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