From 5ba18b186c979283a2bf75a28b7ea325184b0c08 Mon Sep 17 00:00:00 2001
From: Roland Dreier <rolandd@cisco.com>
Date: Thu, 24 Jul 2008 20:36:59 -0700
Subject: [PATCH] RDMA/ucm: BKL is not needed for ib_ucm_open()
Remove explicit cycle_kernel_lock() call and document why the code is safe.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
---
drivers/infiniband/core/ucm.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index 9494005d1c9a62..e603736682bfc6 100644
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -43,7 +43,6 @@
#include <linux/cdev.h>
#include <linux/idr.h>
#include <linux/mutex.h>
-#include <linux/smp_lock.h>
#include <asm/uaccess.h>
@@ -1154,11 +1153,18 @@ static unsigned int ib_ucm_poll(struct file *filp,
return mask;
}
+/*
+ * ib_ucm_open() does not need the BKL:
+ *
+ * - no global state is referred to;
+ * - there is no ioctl method to race against;
+ * - no further module initialization is required for open to work
+ * after the device is registered.
+ */
static int ib_ucm_open(struct inode *inode, struct file *filp)
{
struct ib_ucm_file *file;
- cycle_kernel_lock();
file = kmalloc(sizeof(*file), GFP_KERNEL);
if (!file)
return -ENOMEM;
--
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