[PATCH 1/1] device-dax: avoid an unnecessary check in alloc_dev_dax_range()

[Zhen Lei]

Swap the calling sequence of krealloc() and __request_region(), call the
latter first. In this way, the value of dev_dax->nr_range does not need to
be considered when __request_region() failed.

Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com>
---
 drivers/dax/bus.c | 29 ++++++++++++-----------------
 1 file changed, 12 insertions(+), 17 deletions(-)

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 27513d311242..1efae11d947a 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -763,23 +763,15 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, 
u64 start,
                return 0;
        }
 
-       ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
-                       * (dev_dax->nr_range + 1), GFP_KERNEL);
-       if (!ranges)
-               return -ENOMEM;
-
        alloc = __request_region(res, start, size, dev_name(dev), 0);
-       if (!alloc) {
-               /*
-                * If this was an empty set of ranges nothing else
-                * will release @ranges, so do it now.
-                */
-               if (!dev_dax->nr_range) {
-                       kfree(ranges);
-                       ranges = NULL;
-               }
-               dev_dax->ranges = ranges;
+       if (!alloc)
                return -ENOMEM;
+
+       ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
+                       * (dev_dax->nr_range + 1), GFP_KERNEL);
+       if (!ranges) {
+               rc = -ENOMEM;
+               goto err;
        }
 
        for (i = 0; i < dev_dax->nr_range; i++)
@@ -808,11 +800,14 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, 
u64 start,
                dev_dbg(dev, "delete range[%d]: %pa:%pa\n", dev_dax->nr_range - 
1,
                                &alloc->start, &alloc->end);
                dev_dax->nr_range--;
-               __release_region(res, alloc->start, resource_size(alloc));
-               return rc;
+               goto err;
        }
 
        return 0;
+
+err:
+       __release_region(res, alloc->start, resource_size(alloc));
+       return rc;
 }
 
 static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, 
resource_size_t size)
-- 
2.26.0.106.g9fadedd