[PATCH] Change the spin_lock/unlock_irq interface in proc_alloc_inum() function

[MaJun]

From: Ma Jun <majun...@huawei.com>

The spin_lock/unlock_irq interface is not safe when this function is called
at some case which need irq disabled.

For example:
        spin_lock_irqsave()
        |
        request_irq() --> proc_alloc_inum()
        |
        spin_unlock_irqrestore()

Reported-by: Fan Jinke <fanjin...@huawei.com>
Signed-off-by: Ma Jun <majun...@huawei.com>
---
 fs/proc/generic.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index ff3ffc7..4fc1502 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -191,23 +191,24 @@ int proc_alloc_inum(unsigned int *inum)
 {
        unsigned int i;
        int error;
+       unsigned long flags;
 
 retry:
        if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
                return -ENOMEM;
 
-       spin_lock_irq(&proc_inum_lock);
+       spin_lock_irqsave(&proc_inum_lock, flags);
        error = ida_get_new(&proc_inum_ida, &i);
-       spin_unlock_irq(&proc_inum_lock);
+       spin_unlock_irqrestore(&proc_inum_lock, flags);
        if (error == -EAGAIN)
                goto retry;
        else if (error)
                return error;
 
        if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
-               spin_lock_irq(&proc_inum_lock);
+               spin_lock_irqsave(&proc_inum_lock, flags);
                ida_remove(&proc_inum_ida, i);
-               spin_unlock_irq(&proc_inum_lock);
+               spin_unlock_irqrestore(&proc_inum_lock, flags);
                return -ENOSPC;
        }
        *inum = PROC_DYNAMIC_FIRST + i;
-- 
1.7.1