[PATCH net-next 06/15] nfp: lock area cache earlier

[Jakub Kicinski]

We shouldn't access area_cache_list without its lock even
to check if it's empty.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c 
b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
index 4e08362d8c97..5189fedb0f4f 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
@@ -821,10 +821,7 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
         * the need for special case code below when
         * checking against available cache size.
         */
-       if (length == 0)
-               return NULL;
-
-       if (list_empty(&cpp->area_cache_list) || id == 0)
+       if (length == 0 || id == 0)
                return NULL;
 
        /* Remap from cpp_island to cpp_target */
@@ -832,10 +829,15 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
        if (err < 0)
                return NULL;
 
-       addr += *offset;
-
        mutex_lock(&cpp->area_cache_mutex);
 
+       if (list_empty(&cpp->area_cache_list)) {
+               mutex_unlock(&cpp->area_cache_mutex);
+               return NULL;
+       }
+
+       addr += *offset;
+
        /* See if we have a match */
        list_for_each_entry(cache, &cpp->area_cache_list, entry) {
                if (id == cache->id &&
-- 
2.11.0