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uprobes: Turn add_utask() into get_utask()

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Rename add_utask() into get_utask() and change it to allocate on
demand to simplify the caller. Like get_xol_area() it will have
more users.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
This commit is contained in:
Oleg Nesterov 2012-12-31 17:03:32 +01:00
parent 9b545df809
commit 5a2df662aa
1 changed files with 9 additions and 18 deletions
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27
kernel/events/uprobes.c
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@ -1290,23 +1290,18 @@ void uprobe_copy_process(struct task_struct *t)
} }
/* /*
* Allocate a uprobe_task object for the task. * Allocate a uprobe_task object for the task if if necessary.
* Called when the thread hits a breakpoint for the first time. * Called when the thread hits a breakpoint.
* *
* Returns: * Returns:
* - pointer to new uprobe_task on success * - pointer to new uprobe_task on success
* - NULL otherwise * - NULL otherwise
*/ */
static struct uprobe_task *add_utask(void) static struct uprobe_task *get_utask(void)
{ {
struct uprobe_task *utask; if (!current->utask)
current->utask = kzalloc(sizeof(struct uprobe_task), GFP_KERNEL);
utask = kzalloc(sizeof *utask, GFP_KERNEL); return current->utask;
if (unlikely(!utask))
return NULL;
current->utask = utask;
return utask;
} }
/* Prepare to single-step probed instruction out of line. */ /* Prepare to single-step probed instruction out of line. */
@ -1505,13 +1500,9 @@ static void handle_swbp(struct pt_regs *regs)
if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags))) if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))
goto out; goto out;
utask = current->utask; utask = get_utask();
if (!utask) { if (!utask)
utask = add_utask(); goto out; /* re-execute the instruction. */
/* Cannot allocate; re-execute the instruction. */
if (!utask)
goto out;
}
handler_chain(uprobe, regs); handler_chain(uprobe, regs);
if (can_skip_sstep(uprobe, regs)) if (can_skip_sstep(uprobe, regs))