uprobes: Introduce get_uprobe()

Cosmetic. Add the new trivial helper, get_uprobe(). It matches
put_uprobe() we already have and we can simplify a couple of its
users.

Tested-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Anton Arapov <arapov@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150721134003.GA4736@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 20 insertions, 19 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index cb346f26a22d..a9847b4ec1e7 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -366,6 +366,18 @@ set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long v
         return uprobe_write_opcode(mm, vaddr, *(uprobe_opcode_t *)&auprobe->insn);
 }
 
+static struct uprobe *get_uprobe(struct uprobe *uprobe)
+{
+        atomic_inc(&uprobe->ref);
+        return uprobe;
+}
+
+static void put_uprobe(struct uprobe *uprobe)
+{
+        if (atomic_dec_and_test(&uprobe->ref))
+                kfree(uprobe);
+}
+
 static int match_uprobe(struct uprobe *l, struct uprobe *r)
 {
         if (l->inode < r->inode)
@@ -393,10 +405,8 @@ static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset)
         while (n) {
                 uprobe = rb_entry(n, struct uprobe, rb_node);
                 match = match_uprobe(&u, uprobe);
-                if (!match) {
-                        atomic_inc(&uprobe->ref);
-                        return uprobe;
-                }
+                if (!match)
+                        return get_uprobe(uprobe);
 
                 if (match < 0)
                         n = n->rb_left;
@@ -432,10 +442,8 @@ static struct uprobe *__insert_uprobe(struct uprobe *uprobe)
                 parent = *p;
                 u = rb_entry(parent, struct uprobe, rb_node);
                 match = match_uprobe(uprobe, u);
-                if (!match) {
-                        atomic_inc(&u->ref);
-                        return u;
-                }
+                if (!match)
+                        return get_uprobe(u);
 
                 if (match < 0)
                         p = &parent->rb_left;
@@ -472,12 +480,6 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe)
         return u;
 }
 
-static void put_uprobe(struct uprobe *uprobe)
-{
-        if (atomic_dec_and_test(&uprobe->ref))
-                kfree(uprobe);
-}
-
 static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
 {
         struct uprobe *uprobe, *cur_uprobe;
@@ -1039,14 +1041,14 @@ static void build_probe_list(struct inode *inode,
                         if (u->inode != inode || u->offset < min)
                                 break;
                         list_add(&u->pending_list, head);
-                        atomic_inc(&u->ref);
+                        get_uprobe(u);
                 }
                 for (t = n; (t = rb_next(t)); ) {
                         u = rb_entry(t, struct uprobe, rb_node);
                         if (u->inode != inode || u->offset > max)
                                 break;
                         list_add(&u->pending_list, head);
-                        atomic_inc(&u->ref);
+                        get_uprobe(u);
                 }
         }
         spin_unlock(&uprobes_treelock);
@@ -1437,7 +1439,7 @@ static int dup_utask(struct task_struct *t, struct uprobe_task *o_utask)
                         return -ENOMEM;
 
                 *n = *o;
-                atomic_inc(&n->uprobe->ref);
+                get_uprobe(n->uprobe);
                 n->next = NULL;
 
                 *p = n;
@@ -1565,8 +1567,7 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
                 orig_ret_vaddr = utask->return_instances->orig_ret_vaddr;
         }
 
-        atomic_inc(&uprobe->ref);
-        ri->uprobe = uprobe;
+        ri->uprobe = get_uprobe(uprobe);
         ri->func = instruction_pointer(regs);
         ri->orig_ret_vaddr = orig_ret_vaddr;
         ri->chained = chained;