cpumask: Add helper cpumask_available()

Matthias Kaehlcke · KAGA-KOKO · commit f7e30f01a9e2 · 2017-04-14T19:50:47.000+02:00
With CONFIG_CPUMASK_OFFSTACK=y cpumask_var_t is a struct cpumask pointer, otherwise a struct cpumask array with a single element. Some code dealing with cpumasks needs to validate that a cpumask_var_t is not a NULL pointer when CONFIG_CPUMASK_OFFSTACK=y. This is typically done by performing the check always, regardless of the underlying type of cpumask_var_t. This works in both cases, however clang raises a warning like this when CONFIG_CPUMASK_OFFSTACK=n: kernel/irq/manage.c:839:28: error: address of array 'desc->irq_common_data.affinity' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion] Add the inline helper cpumask_available() which only performs the pointer check if CONFIG_CPUMASK_OFFSTACK=y. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Cc: Grant Grundler <grundler@chromium.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Greg Hackmann <ghackmann@google.com> Cc: Michael Davidson <md@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20170412182030.83657-1-mka@chromium.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
@@ -667,6 +667,11 @@ void alloc_bootmem_cpumask_var(cpumask_var_t *mask);
 void free_cpumask_var(cpumask_var_t mask);
 void free_bootmem_cpumask_var(cpumask_var_t mask);
 
+static inline bool cpumask_available(cpumask_var_t mask)
+{
+	return mask != NULL;
+}
+
 #else
 typedef struct cpumask cpumask_var_t[1];
 
@@ -708,6 +713,11 @@ static inline void free_cpumask_var(cpumask_var_t mask)
 static inline void free_bootmem_cpumask_var(cpumask_var_t mask)
 {
 }
+
+static inline bool cpumask_available(cpumask_var_t mask)
+{
+	return true;
+}
 #endif /* CONFIG_CPUMASK_OFFSTACK */
 
 /* It's common to want to use cpu_all_mask in struct member initializers,
