4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matthias Kaehlcke mka@chromium.org
commit f7e30f01a9e221067bb4b579e3cfc25cd2617467 upstream.
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 Cc: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/linux/cpumask.h | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -680,6 +680,11 @@ void alloc_bootmem_cpumask_var(cpumask_v 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];
@@ -720,6 +725,11 @@ static inline void free_cpumask_var(cpum 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,