linux-kernel - [PATCH 2/7] uprobes: Fold xol_alloc_area() into get_xol

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20121231175216.GA32091@redhat.com>
Date:	Mon, 31 Dec 2012 18:52:16 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Ingo Molnar <mingo@...e.hu>, Peter Zijlstra <peterz@...radead.org>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anton Arapov <anton@...hat.com>,
	Frank Eigler <fche@...hat.com>,
	Josh Stone <jistone@...hat.com>,
	"Suzuki K. Poulose" <suzuki@...ibm.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/7] uprobes: Fold xol_alloc_area() into get_xol_area()

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@...hat.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.
  */
-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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/