If the preprocessor constant ESP_MAX_DNS is defined as 0,
Coverity reports a condition that can never be true, and some
dead code as well. This also violates MISRA rules on dead code.
This is caused by this segment in drivers/wifi/esp_at/esp.h:
#if defined(CONFIG_WIFI_ESP_AT_DNS_USE)
#define ESP_MAX_DNS MIN(3, CONFIG_DNS_RESOLVER_MAX_SERVERS)
#else
#define ESP_MAX_DNS 0
#endif
Fix this by never setting ESP_MAX_DNS to 0, as is the currently
case. Define ESP_MAX_DNS only if it is configured through
CONFIG_WIFI_ESP_AT_DNS_USE and CONFIG_DNS_RESOLVER_MAX_SERVERS:
#if defined(CONFIG_WIFI_ESP_AT_DNS_USE)
#define ESP_MAX_DNS MIN(3, CONFIG_DNS_RESOLVER_MAX_SERVERS)
#endif
Since CONFIG_DNS_RESOLVER_MAX_SERVERS is 1 or greater, ESP_MAX_DNS
will always be greater than 0.
If, on the other hand, ESP_MAX_DNS is not defined, relevant
functions will be reduced to empty stubs, since in that case
they do not make sense.
There could be a cleaner solution to this, but this one is the
least intrusive (involves less code changes).
Coverity-CID: 219490
Coverity-CID: 219513
Coverity-CID: 219520
Coverity-CID: 219524
Signed-off-by: Aleksandar Markovic <aleksandar.markovic.sa@gmail.com>