include/linux/memory.h: implement register_hotmemory_notifier() (f02c6968) · Commits · 戴 / test

When CONFIG_MEMORY_HOTPLUG=n, we don't want the memory-hotplug notifier handlers to be included in the .o files, for space reasons. The existing hotplug_memory_notifier() tries to handle this but testing with gcc-4.4.4 shows that it doesn't work - the hotplug functions are still present in the .o files. So implement a new register_hotmemory_notifier() which is a copy of register_hotcpu_notifier(), and which actually works as desired. hotplug_memory_notifier() and register_memory_notifier() callsites should be converted to use this new register_hotmemory_notifier(). While we're there, let's repair the existing hotplug_memory_notifier(): it simply stomps on the register_memory_notifier() return value, so well-behaved code cannot check for errors. Apparently non of the existing callers were well-behaved :( Cc: Andrew Shewmaker <agshew@gmail.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memory.h

+10 −4

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@
		#include <linux/node.h>
		#include <linux/compiler.h>
		#include <linux/mutex.h>
		#include <linux/notifier.h>

		#define MIN_MEMORY_BLOCK_SIZE (1UL << SECTION_SIZE_BITS)

		@@ -127,13 +128,18 @@ enum mem_add_context { BOOT, HOTPLUG };
		#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */

		#ifdef CONFIG_MEMORY_HOTPLUG
		#define hotplug_memory_notifier(fn, pri) { \
		#define hotplug_memory_notifier(fn, pri) ({ \
		static __meminitdata struct notifier_block fn##_mem_nb =\
		{ .notifier_call = fn, .priority = pri };\
		register_memory_notifier(&fn##_mem_nb); \
		}
		})
		#define register_hotmemory_notifier(nb) register_memory_notifier(nb)
		#define unregister_hotmemory_notifier(nb) unregister_memory_notifier(nb)
		#else
		#define hotplug_memory_notifier(fn, pri) do { } while (0)
		#define hotplug_memory_notifier(fn, pri) (0)
		/* These aren't inline functions due to a GCC bug. */
		#define register_hotmemory_notifier(nb) ({ (void)(nb); 0; })
		#define unregister_hotmemory_notifier(nb) ({ (void)(nb); })
		#endif

		/*

include/linux/notifier.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -47,8 +47,11 @@
		* runtime initialization.
		*/

		typedef int (notifier_fn_t)(struct notifier_block nb,
		unsigned long action, void *data);

		struct notifier_block {
		int (notifier_call)(struct notifier_block , unsigned long, void *);
		notifier_fn_t notifier_call;
		struct notifier_block __rcu *next;
		int priority;
		};

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