Messages in this thread Patch in this message |  | | Date | Wed, 9 Jan 2013 11:16:54 +0100 | From | Anton Arapov <> | Subject | Re: [PATCH 2/7] uprobes: Fold xol_alloc_area() into get_xol_area() |
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On Mon, Dec 31, 2012 at 06:52:16PM +0100, Oleg Nesterov wrote: > Currently only xol_get_insn_slot() does get_xol_area() + xol_alloc_area(), > but this will have more users and we do not want to copy-and-paste this > code. This patch simply moves xol_alloc_area() into get_xol_area() to > simplify the current and future code. > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > --- > kernel/events/uprobes.c | 38 ++++++++++++++++---------------------- > 1 files changed, 16 insertions(+), 22 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index 1456f7d..ef81162 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -1070,27 +1070,21 @@ static int xol_add_vma(struct xol_area *area) > return ret; > } > > -static struct xol_area *get_xol_area(struct mm_struct *mm) > -{ > - struct xol_area *area; > - > - area = mm->uprobes_state.xol_area; > - smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */ > - > - return area; > -} > - > /* > - * xol_alloc_area - Allocate process's xol_area. > - * This area will be used for storing instructions for execution out of > - * line. > + * get_alloc_area - Allocate process's xol_area if necessary. > + * This area will be used for storing instructions for execution out of line. > * > * Returns the allocated area or NULL. > */
+ * get_xol_area ....
Anton.
> -static struct xol_area *xol_alloc_area(void) > +static struct xol_area *get_xol_area(void) > { > + struct mm_struct *mm = current->mm; > struct xol_area *area; > > + area = mm->uprobes_state.xol_area; > + if (area) > + goto ret; > + > area = kzalloc(sizeof(*area), GFP_KERNEL); > if (unlikely(!area)) > goto out; > @@ -1113,7 +1107,10 @@ static struct xol_area *xol_alloc_area(void) > free_area: > kfree(area); > out: > - return get_xol_area(current->mm); > + area = mm->uprobes_state.xol_area; > + ret: > + smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */ > + return area; > } > > /* > @@ -1189,14 +1186,11 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot > unsigned long offset; > void *vaddr; > > - area = get_xol_area(current->mm); > - if (!area) { > - area = xol_alloc_area(); > - if (!area) > - return 0; > - } > - current->utask->xol_vaddr = xol_take_insn_slot(area); > + area = get_xol_area(); > + if (!area) > + return 0; > > + current->utask->xol_vaddr = xol_take_insn_slot(area); > /* > * Initialize the slot if xol_vaddr points to valid > * instruction slot. > -- > 1.5.5.1 >
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