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>

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index cb346f26a22de1d618edc19f2c10300a5850c4c9..a9847b4ec1e7cb961fae293e85ee2ee147802b80 100644 (file)
--- 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;