Commit-ID: 608e7427c0a06de0d70374a9fd7defc8eb228b7e
Gitweb: http://git.kernel.org/tip/608e7427c0a06de0d70374a9fd7defc8eb228b7e
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Mon, 31 Dec 2012 18:20:42 +0100
Committer: Oleg Nesterov <oleg@xxxxxxxxxx>
CommitDate: Fri, 8 Feb 2013 17:47:12 +0100
uprobes: Do not allocate current->utask unnecessary
handle_swbp() does get_utask() before can_skip_sstep() for no reason,
we do not need ->utask if can_skip_sstep() succeeds.
Move get_utask() to pre_ssout() who actually starts to use it. Move
the initialization of utask->active_uprobe/state as well. This way
the whole initialization is consolidated in pre_ssout().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Anton Arapov <anton@xxxxxxxxxx>
---
kernel/events/uprobes.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 0527379..071edcb 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1308,7 +1308,9 @@ pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
unsigned long xol_vaddr;
int err;
- utask = current->utask;
+ utask = get_utask();
+ if (!utask)
+ return -ENOMEM;
xol_vaddr = xol_get_insn_slot(uprobe);
if (!xol_vaddr)
@@ -1323,6 +1325,8 @@ pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
return err;
}
+ utask->active_uprobe = uprobe;
+ utask->state = UTASK_SSTEP;
return 0;
}
@@ -1474,7 +1478,6 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
*/
static void handle_swbp(struct pt_regs *regs)
{
- struct uprobe_task *utask;
struct uprobe *uprobe;
unsigned long bp_vaddr;
int uninitialized_var(is_swbp);
@@ -1512,19 +1515,12 @@ static void handle_swbp(struct pt_regs *regs)
if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))
goto out;
- utask = get_utask();
- if (!utask)
- goto out; /* re-execute the instruction. */
-
handler_chain(uprobe, regs);
if (can_skip_sstep(uprobe, regs))
goto out;
- if (!pre_ssout(uprobe, regs, bp_vaddr)) {
- utask->active_uprobe = uprobe;
- utask->state = UTASK_SSTEP;
+ if (!pre_ssout(uprobe, regs, bp_vaddr))
return;
- }
/* can_skip_sstep() succeeded, or restart if can't singlestep */
out:
--
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