hwmon: convert idr to ida and use ida_simple interface

hwmon was using an idr with a NULL pointer, so convert to an
ida which then allows use of Rusty's ida_simple_get.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 24 deletions

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index a61e7815a2a..6460487e41b 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -27,8 +27,7 @@
 
 static struct class *hwmon_class;
 
-static DEFINE_IDR(hwmon_idr);
-static DEFINE_SPINLOCK(idr_lock);
+static DEFINE_IDA(hwmon_ida);
 
 /**
  * hwmon_device_register - register w/ hwmon
@@ -42,30 +41,17 @@ static DEFINE_SPINLOCK(idr_lock);
 struct device *hwmon_device_register(struct device *dev)
 {
         struct device *hwdev;
-        int id, err;
-
-again:
-        if (unlikely(idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0))
-                return ERR_PTR(-ENOMEM);
-
-        spin_lock(&idr_lock);
-        err = idr_get_new(&hwmon_idr, NULL, &id);
-        spin_unlock(&idr_lock);
+        int id;
 
-        if (unlikely(err == -EAGAIN))
-                goto again;
-        else if (unlikely(err))
-                return ERR_PTR(err);
+        id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
+        if (id < 0)
+                return ERR_PTR(id);
 
-        id = id & MAX_ID_MASK;
         hwdev = device_create(hwmon_class, dev, MKDEV(0, 0), NULL,
                               HWMON_ID_FORMAT, id);
 
-        if (IS_ERR(hwdev)) {
-                spin_lock(&idr_lock);
-                idr_remove(&hwmon_idr, id);
-                spin_unlock(&idr_lock);
-        }
+        if (IS_ERR(hwdev))
+                ida_simple_remove(&hwmon_ida, id);
 
         return hwdev;
 }
@@ -81,9 +67,7 @@ void hwmon_device_unregister(struct device *dev)
 
         if (likely(sscanf(dev_name(dev), HWMON_ID_FORMAT, &id) == 1)) {
                 device_unregister(dev);
-                spin_lock(&idr_lock);
-                idr_remove(&hwmon_idr, id);
-                spin_unlock(&idr_lock);
+                ida_simple_remove(&hwmon_ida, id);
         } else
                 dev_dbg(dev->parent,
                         "hwmon_device_unregister() failed: bad class ID!\n");