[PATCH] nfp: Improve unlocking of a mutex in area_cache_get()

[SF Markus Elfring]

From: Markus Elfring <elfr...@users.sourceforge.net>
Date: Sat, 28 Oct 2017 17:12:10 +0200

Add a jump target so that a call of the function "mutex_unlock" is stored
only once at the end of this function implementation.
Replace four calls by goto statements.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfr...@users.sourceforge.net>
---
 .../ethernet/netronome/nfp/nfpcore/nfp_cppcore.c   | 28 ++++++++++------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c 
b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
index 04dd5758ecf5..e864793b7ca0 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
@@ -822,10 +822,8 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
 
        mutex_lock(&cpp->area_cache_mutex);
 
-       if (list_empty(&cpp->area_cache_list)) {
-               mutex_unlock(&cpp->area_cache_mutex);
-               return NULL;
-       }
+       if (list_empty(&cpp->area_cache_list))
+               goto unlock;
 
        addr += *offset;
 
@@ -843,10 +841,8 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
 
        /* Can we fit in the cache entry? */
        if (round_down(addr + length - 1, cache->size) !=
-           round_down(addr, cache->size)) {
-               mutex_unlock(&cpp->area_cache_mutex);
-               return NULL;
-       }
+           round_down(addr, cache->size))
+               goto unlock;
 
        /* If id != 0, we will need to release it */
        if (cache->id) {
@@ -863,23 +859,23 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
        if (cpp->op->area_init) {
                err = cpp->op->area_init(cache->area,
                                         id, cache->addr, cache->size);
-               if (err < 0) {
-                       mutex_unlock(&cpp->area_cache_mutex);
-                       return NULL;
-               }
+               if (err < 0)
+                       goto unlock;
        }
 
        /* Attempt to acquire */
        err = nfp_cpp_area_acquire(cache->area);
-       if (err < 0) {
-               mutex_unlock(&cpp->area_cache_mutex);
-               return NULL;
-       }
+       if (err < 0)
+               goto unlock;
 
 exit:
        /* Adjust offset */
        *offset = addr - cache->addr;
        return cache;
+
+unlock:
+       mutex_unlock(&cpp->area_cache_mutex);
+       return NULL;
 }
 
 static void
-- 
2.14.3