Commit 56f434f4 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

mm/mmu_notifier: define the header pre-processor parts even if disabled 

Now that we have KERNEL_HEADER_TEST all headers are generally compile
tested, so relying on makefile tricks to avoid compiling code that depends
on CONFIG_MMU_NOTIFIER is more annoying.

Instead follow the usual pattern and provide most of the header with only
the functions stubbed out when CONFIG_MMU_NOTIFIER is disabled. This
ensures code compiles no matter what the config setting is.

While here, struct mmu_notifier_mm is private to mmu_notifier.c, move it.

Link: https://lore.kernel.org/r/20191112202231.3856-2-jgg@ziepe.ca


Reviewed-by: default avatarJérôme Glisse <jglisse@redhat.com>
Tested-by: default avatarRalph Campbell <rcampbell@nvidia.com>
Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent 0e64e5b3

include/linux/mmu_notifier.h

+17 −29
Original line number Diff line number Diff line
@@ -7,8 +7,9 @@ 
#include <linux/mm_types.h>

#include <linux/srcu.h>



struct mmu_notifier_mm;

struct mmu_notifier;

struct mmu_notifier_ops;

struct mmu_notifier_range;



/**

 * enum mmu_notifier_event - reason for the mmu notifier callback
@@ -40,36 +41,8 @@ enum mmu_notifier_event { 
	MMU_NOTIFY_SOFT_DIRTY,

};



#ifdef CONFIG_MMU_NOTIFIER



#ifdef CONFIG_LOCKDEP

extern struct lockdep_map __mmu_notifier_invalidate_range_start_map;

#endif



/*

 * The mmu notifier_mm structure is allocated and installed in

 * mm->mmu_notifier_mm inside the mm_take_all_locks() protected

 * critical section and it's released only when mm_count reaches zero

 * in mmdrop().

 */

struct mmu_notifier_mm {

	/* all mmu notifiers registerd in this mm are queued in this list */

	struct hlist_head list;

	/* to serialize the list modifications and hlist_unhashed */

	spinlock_t lock;

};



#define MMU_NOTIFIER_RANGE_BLOCKABLE (1 << 0)



struct mmu_notifier_range {

	struct vm_area_struct *vma;

	struct mm_struct *mm;

	unsigned long start;

	unsigned long end;

	unsigned flags;

	enum mmu_notifier_event event;

};



struct mmu_notifier_ops {

	/*

	 * Called either by mmu_notifier_unregister or when the mm is
@@ -249,6 +222,21 @@ struct mmu_notifier { 
	unsigned int users;

};



#ifdef CONFIG_MMU_NOTIFIER



#ifdef CONFIG_LOCKDEP

extern struct lockdep_map __mmu_notifier_invalidate_range_start_map;

#endif



struct mmu_notifier_range {

	struct vm_area_struct *vma;

	struct mm_struct *mm;

	unsigned long start;

	unsigned long end;

	unsigned flags;

	enum mmu_notifier_event event;

};



static inline int mm_has_notifiers(struct mm_struct *mm)

{

	return unlikely(mm->mmu_notifier_mm);

mm/mmu_notifier.c

+13 −0
Original line number Diff line number Diff line
@@ -27,6 +27,19 @@ struct lockdep_map __mmu_notifier_invalidate_range_start_map = { 
};

#endif



/*

 * The mmu notifier_mm structure is allocated and installed in

 * mm->mmu_notifier_mm inside the mm_take_all_locks() protected

 * critical section and it's released only when mm_count reaches zero

 * in mmdrop().

 */

struct mmu_notifier_mm {

	/* all mmu notifiers registered in this mm are queued in this list */

	struct hlist_head list;

	/* to serialize the list modifications and hlist_unhashed */

	spinlock_t lock;

};



/*

 * This function can't run concurrently against mmu_notifier_register

 * because mm->mm_users > 0 during mmu_notifier_register and exit_mmap

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