> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 4fa360a13c1e..82f84cfe372f 100644
> +++ b/include/linux/kernel.h
> @@ -217,7 +217,9 @@ extern void __cant_sleep(const char *file, int line, int
> preempt_offset);
> * might_sleep - annotation for functions that can sleep
> *
> * this macro will print a stack trace if it is executed in an atomic
> - * context (spinlock, irq-handler, ...).
> + * context (spinlock, irq-handler, ...). Additional sections where blocking
> is
> + * not allowed can be annotated with non_block_start() and non_block_end()
> + * pairs.
> *
> * This is a useful debugging help to be able to catch problems early and not
> * be bitten later when the calling function happens to sleep when it is not
> @@ -233,6 +235,25 @@ extern void __cant_sleep(const char *file, int line, int
> preempt_offset);
> # define cant_sleep() \
> do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
> # define sched_annotate_sleep() (current->task_state_change = 0)
> +/**
> + * non_block_start - annotate the start of section where sleeping is
> prohibited
> + *
> + * This is on behalf of the oom reaper, specifically when it is calling the
> mmu
> + * notifiers. The problem is that if the notifier were to block on, for
> example,
> + * mutex_lock() and if the process which holds that mutex were to perform a
> + * sleeping memory allocation, the oom reaper is now blocked on completion of
> + * that memory allocation. Other blocking calls like wait_event() pose
> similar
> + * issues.
> + */
> +# define non_block_start() \
> + do { current->non_block_count++; } while (0)
> +/**
> + * non_block_end - annotate the end of section where sleeping is prohibited
> + *
> + * Closes a section opened by non_block_start().
> + */
> +# define non_block_end() \
> + do { WARN_ON(current->non_block_count-- == 0); } while (0)
check-patch does not like these, and I agree
#101: FILE: include/linux/kernel.h:248:
+# define non_block_start() \
+ do { current->non_block_count++; } while (0)
/tmp/tmp1spfxufy/0006-kernel-h-Add-non_block_start-end-.patch:108: WARNING:
Single statement macros should not use a do {} while (0) loop
#108: FILE: include/linux/kernel.h:255:
+# define non_block_end() \
+ do { WARN_ON(current->non_block_count-- == 0); } while (0)
Please use a static inline?
Also, can we get one more ack on this patch?
Jason
