From: Jason Gunthorpe jgg@mellanox.com
Only the function calls are stubbed out with static inlines that always fail. This is the standard way to write a header for an optional component and makes it easier for drivers that only optionally need HMM_MIRROR.
Reviewed-by: Jérôme Glisse jglisse@redhat.com Tested-by: Ralph Campbell rcampbell@nvidia.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com --- include/linux/hmm.h | 59 ++++++++++++++++++++++++++++++++++++--------- kernel/fork.c | 1 - 2 files changed, 47 insertions(+), 13 deletions(-)
diff --git a/include/linux/hmm.h b/include/linux/hmm.h index fbb35c78637e57..cb69bf10dc788c 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -62,8 +62,6 @@ #include <linux/kconfig.h> #include <asm/pgtable.h>
-#ifdef CONFIG_HMM_MIRROR - #include <linux/device.h> #include <linux/migrate.h> #include <linux/memremap.h> @@ -374,6 +372,15 @@ struct hmm_mirror { struct list_head list; };
+/* + * Retry fault if non-blocking, drop mmap_sem and return -EAGAIN in that case. + */ +#define HMM_FAULT_ALLOW_RETRY (1 << 0) + +/* Don't fault in missing PTEs, just snapshot the current state. */ +#define HMM_FAULT_SNAPSHOT (1 << 1) + +#ifdef CONFIG_HMM_MIRROR int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm); void hmm_mirror_unregister(struct hmm_mirror *mirror);
@@ -383,14 +390,6 @@ void hmm_mirror_unregister(struct hmm_mirror *mirror); int hmm_range_register(struct hmm_range *range, struct hmm_mirror *mirror); void hmm_range_unregister(struct hmm_range *range);
-/* - * Retry fault if non-blocking, drop mmap_sem and return -EAGAIN in that case. - */ -#define HMM_FAULT_ALLOW_RETRY (1 << 0) - -/* Don't fault in missing PTEs, just snapshot the current state. */ -#define HMM_FAULT_SNAPSHOT (1 << 1) - long hmm_range_fault(struct hmm_range *range, unsigned int flags);
long hmm_range_dma_map(struct hmm_range *range, @@ -401,6 +400,44 @@ long hmm_range_dma_unmap(struct hmm_range *range, struct device *device, dma_addr_t *daddrs, bool dirty); +#else +int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm) +{ + return -EOPNOTSUPP; +} + +void hmm_mirror_unregister(struct hmm_mirror *mirror) +{ +} + +int hmm_range_register(struct hmm_range *range, struct hmm_mirror *mirror) +{ + return -EOPNOTSUPP; +} + +void hmm_range_unregister(struct hmm_range *range) +{ +} + +static inline long hmm_range_fault(struct hmm_range *range, unsigned int flags) +{ + return -EOPNOTSUPP; +} + +static inline long hmm_range_dma_map(struct hmm_range *range, + struct device *device, dma_addr_t *daddrs, + unsigned int flags) +{ + return -EOPNOTSUPP; +} + +static inline long hmm_range_dma_unmap(struct hmm_range *range, + struct device *device, + dma_addr_t *daddrs, bool dirty) +{ + return -EOPNOTSUPP; +} +#endif
/* * HMM_RANGE_DEFAULT_TIMEOUT - default timeout (ms) when waiting for a range @@ -411,6 +448,4 @@ long hmm_range_dma_unmap(struct hmm_range *range, */ #define HMM_RANGE_DEFAULT_TIMEOUT 1000
-#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */ - #endif /* LINUX_HMM_H */ diff --git a/kernel/fork.c b/kernel/fork.c index bcdf5312521036..ca39cfc404e3db 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -40,7 +40,6 @@ #include <linux/binfmts.h> #include <linux/mman.h> #include <linux/mmu_notifier.h> -#include <linux/hmm.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/vmacache.h>