From: Arnd Bergmann <arnd@xxxxxxxx> Subject: mm: add dummy can_do_mlock() helper On kernels without CONFIG_MMU, we get a link error for the siw driver: drivers/infiniband/sw/siw/siw_mem.o: In function `siw_umem_get': siw_mem.c:(.text+0x4c8): undefined reference to `can_do_mlock' This is probably not the only driver that needs the function and could otherwise build correctly without CONFIG_MMU, so add a dummy variant that always returns false. Link: http://lkml.kernel.org/r/20190909204201.931830-1-arnd@xxxxxxxx Fixes: 2251334dcac9 ("rdma/siw: application buffer management") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Bernard Metzler <bmt@xxxxxxxxxxxxxx> Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mm.h | 4 ++++ 1 file changed, 4 insertions(+) --- a/include/linux/mm.h~mm-add-dummy-can_do_mlock-helper +++ a/include/linux/mm.h @@ -1405,7 +1405,11 @@ extern void pagefault_out_of_memory(void extern void show_free_areas(unsigned int flags, nodemask_t *nodemask); +#ifdef CONFIG_MMU extern bool can_do_mlock(void); +#else +static inline bool can_do_mlock(void) { return false; } +#endif extern int user_shm_lock(size_t, struct user_struct *); extern void user_shm_unlock(size_t, struct user_struct *); _
