env: Explicitly fail calls to spdk_malloc with flags of 0

Passing no flags to spdk_malloc is not a valid usage. Instead,
just call POSIX malloc.

Change-Id: I759e2c0c0befeb4983df953edd1529d6359b4c55
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/410479
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>

include/spdk/env.h

@@ -94,6 +94,7 @@ struct spdk_env_opts {
  * \param socket_id Socket ID to allocate memory on, or SPDK_ENV_SOCKET_ID_ANY
  * for any socket.
  * \param flags Combination of SPDK_MALLOC flags (\ref SPDK_MALLOC_DMA, \ref SPDK_MALLOC_SHARE).
+ * At least one flag must be specified.
  *
  * \return a pointer to the allocated memory buffer.
  */

lib/env_dpdk/env.c

@@ -65,6 +65,10 @@ virt_to_phys(void *vaddr)
 void *
 spdk_malloc(size_t size, size_t align, uint64_t *phys_addr, int socket_id, uint32_t flags)
 {
+	if (flags == 0) {
+		return NULL;
+	}
+
 	void *buf = rte_malloc_socket(NULL, size, align, socket_id);
 	if (buf && phys_addr) {
 		*phys_addr = virt_to_phys(buf);