qcacmn: Use atomic allocation for all scheduler context scan allocations

In low memory environments using GFP_KERNEL flag may cause
scheduler thread to sleep. Scheduler thread callback handlers
are expected to be atomic in nature to ensure timely execution
of different commands. Move all allocations done by scan module
in scheduler thread context to atomic allocation.

Change-Id: Iee3eafbc00a3afea0687ba67b3041ec0816094cc
CRs-Fixed: 2232553

qdf/linux/src/qdf_mem.c

@@ -1061,7 +1061,7 @@ static void qdf_mem_debug_exit(void)
 }
 
 void *qdf_mem_malloc_debug(size_t size, const char *file, uint32_t line,
-			   void *caller)
+			   void *caller, uint32_t flag)
 {
 	QDF_STATUS status;
 	enum qdf_debug_domain current_domain = qdf_debug_domain_get();
@@ -1079,8 +1079,11 @@ void *qdf_mem_malloc_debug(size_t size, const char *file, uint32_t line,
 	if (ptr)
 		return ptr;
 
+	if (!flag)
+		flag = qdf_mem_malloc_flags();
+
 	start = qdf_mc_timer_get_system_time();
-	header = kzalloc(size + QDF_MEM_DEBUG_SIZE, qdf_mem_malloc_flags());
+	header = kzalloc(size + QDF_MEM_DEBUG_SIZE, flag);
 	duration = qdf_mc_timer_get_system_time() - start;
 
 	if (duration > QDF_MEM_WARN_THRESHOLD)
@@ -1193,6 +1196,37 @@ void *qdf_mem_malloc(size_t size)
 }
 qdf_export_symbol(qdf_mem_malloc);
 
+/**
+ * qdf_mem_malloc_atomic() - allocation QDF memory atomically
+ * @size: Number of bytes of memory to allocate.
+ *
+ * This function will dynamicallly allocate the specified number of bytes of
+ * memory.
+ *
+ * Return:
+ * Upon successful allocate, returns a non-NULL pointer to the allocated
+ * memory.  If this function is unable to allocate the amount of memory
+ * specified (for any reason) it returns NULL.
+ */
+void *qdf_mem_malloc_atomic(size_t size)
+{
+	void *ptr;
+
+	ptr = qdf_mem_prealloc_get(size);
+	if (ptr)
+		return ptr;
+
+	ptr = kzalloc(size, GFP_ATOMIC);
+	if (!ptr)
+		return NULL;
+
+	qdf_mem_kmalloc_inc(ksize(ptr));
+
+	return ptr;
+}
+
+qdf_export_symbol(qdf_mem_malloc_atomic);
+
 /**
  * qdf_mem_free() - free QDF memory
  * @ptr: Pointer to the starting address of the memory to be free'd.