iwlwifi: mvm: avoid harmless -Wmaybe-uninialized warning

gcc is apparently unablel to track the state of the local 'resp_v2'
variable across the kzalloc() function, and warns about the response
variable being used without an initialization:

drivers/net/wireless/intel/iwlwifi/mvm/nvm.c: In function ‘iwl_mvm_update_mcc’:
drivers/net/wireless/intel/iwlwifi/mvm/nvm.c:727:36: warning: ‘mcc_resp_v1’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   resp_cp->n_channels = mcc_resp_v1->n_channels;
drivers/net/wireless/intel/iwlwifi/mvm/nvm.c:721:3: warning: ‘mcc_resp’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   memcpy(resp_cp, mcc_resp, resp_len);

The warning showed up in x86 allmodconfig after my patch to
unhide -Wmaybe-uninitialized warnings by default was merged,
though it always existed in randconfig builds. I did not
catch the warning earlier because I was testing on ARM, which
never produced the warning.

This rearranges the code in a way that improves readability for
both humans and the compiler, and that avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 6fa52430f0b3 ("iwlwifi: mvm: change mcc update API")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c b/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
index 182ec20..7a686f6 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
@@ -666,8 +666,7 @@ iwl_mvm_update_mcc(struct iwl_mvm *mvm, const char *alpha2,
                .mcc = cpu_to_le16(alpha2[0] << 8 | alpha2[1]),
                .source_id = (u8)src_id,
        };
-       struct iwl_mcc_update_resp *mcc_resp, *resp_cp = NULL;
-       struct iwl_mcc_update_resp_v1 *mcc_resp_v1 = NULL;
+       struct iwl_mcc_update_resp *resp_cp;
        struct iwl_rx_packet *pkt;
        struct iwl_host_cmd cmd = {
                .id = MCC_UPDATE_CMD,
@@ -700,34 +699,36 @@ iwl_mvm_update_mcc(struct iwl_mvm *mvm, const char *alpha2,
 
        /* Extract MCC response */
        if (resp_v2) {
-               mcc_resp = (void *)pkt->data;
+               struct iwl_mcc_update_resp *mcc_resp = (void *)pkt->data;
+
                n_channels =  __le32_to_cpu(mcc_resp->n_channels);
+               resp_len = sizeof(struct iwl_mcc_update_resp) +
+                          n_channels * sizeof(__le32);
+               resp_cp = kmemdup(mcc_resp, resp_len, GFP_KERNEL);
        } else {
-               mcc_resp_v1 = (void *)pkt->data;
+               struct iwl_mcc_update_resp_v1 *mcc_resp_v1 = (void *)pkt->data;
+
                n_channels =  __le32_to_cpu(mcc_resp_v1->n_channels);
+               resp_len = sizeof(struct iwl_mcc_update_resp) +
+                          n_channels * sizeof(__le32);
+               resp_cp = kzalloc(resp_len, GFP_KERNEL);
+
+               if (resp_cp) {
+                       resp_cp->status = mcc_resp_v1->status;
+                       resp_cp->mcc = mcc_resp_v1->mcc;
+                       resp_cp->cap = mcc_resp_v1->cap;
+                       resp_cp->source_id = mcc_resp_v1->source_id;
+                       resp_cp->n_channels = mcc_resp_v1->n_channels;
+                       memcpy(resp_cp->channels, mcc_resp_v1->channels,
+                              n_channels * sizeof(__le32));
+               }
        }
 
-       resp_len = sizeof(struct iwl_mcc_update_resp) + n_channels *
-               sizeof(__le32);
-
-       resp_cp = kzalloc(resp_len, GFP_KERNEL);
        if (!resp_cp) {
                ret = -ENOMEM;
                goto exit;
        }
 
-       if (resp_v2) {
-               memcpy(resp_cp, mcc_resp, resp_len);
-       } else {
-               resp_cp->status = mcc_resp_v1->status;
-               resp_cp->mcc = mcc_resp_v1->mcc;
-               resp_cp->cap = mcc_resp_v1->cap;
-               resp_cp->source_id = mcc_resp_v1->source_id;
-               resp_cp->n_channels = mcc_resp_v1->n_channels;
-               memcpy(resp_cp->channels, mcc_resp_v1->channels,
-                      n_channels * sizeof(__le32));
-       }
-
        status = le32_to_cpu(resp_cp->status);
 
        mcc = le16_to_cpu(resp_cp->mcc);