In order to support the RDMA reg_remote_mr function, we must have the ability to get memory pages for an indeterminate amount of time from a remote process. In this case, 'remote' simply means a process that is different from the caller. Functions for getting longterm pages (get_user_pages_longterm) and remote pages (get_user_pages_remote) already exist - this new function combines the functionality of both of them.
Signed-off-by: Joel Nider <jo...@il.ibm.com> Reviewed-by: Mike Rapoport <r...@linux.ibm.com> --- include/linux/mm.h | 28 +++++++++++++++++++++++++--- mm/gup.c | 15 ++++++++++----- 2 files changed, 35 insertions(+), 8 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 80bb640..1f5c72472 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1537,9 +1537,21 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags); #ifdef CONFIG_FS_DAX -long get_user_pages_longterm(unsigned long start, unsigned long nr_pages, - unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas); +long get_user_pages_remote_longterm(struct task_struct *tsk, + struct mm_struct *mm, unsigned long start, + unsigned long nr_pages, unsigned int gup_flags, + struct page **pages, struct vm_area_struct **vmas); + +static inline long get_user_pages_longterm(unsigned long start, + unsigned long nr_pages, + unsigned int gup_flags, + struct page **pages, + struct vm_area_struct **vmas) +{ + return get_user_pages_remote_longterm(current, current->mm, start, + nr_pages, gup_flags, pages, + vmas); +} #else static inline long get_user_pages_longterm(unsigned long start, unsigned long nr_pages, unsigned int gup_flags, @@ -1547,6 +1559,16 @@ static inline long get_user_pages_longterm(unsigned long start, { return get_user_pages(start, nr_pages, gup_flags, pages, vmas); } + +static inline long get_user_pages_remote_longterm(struct task_struct *tsk, + struct mm_struct *mm, unsigned long start, + unsigned long nr_pages, unsigned int gup_flags, + struct page **pages, struct vm_area_struct **vmas) +{ + return get_user_pages_remote(tsk, mm, start, nr_pages, + gup_flags, pages, vmas); +} + #endif /* CONFIG_FS_DAX */ int get_user_pages_fast(unsigned long start, int nr_pages, int write, diff --git a/mm/gup.c b/mm/gup.c index 05acd7e..bcfe5a6 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1139,9 +1139,11 @@ EXPORT_SYMBOL(get_user_pages); * "longterm" == userspace controlled elevated page count lifetime. * Contrast this to iov_iter_get_pages() usages which are transient. */ -long get_user_pages_longterm(unsigned long start, unsigned long nr_pages, - unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas_arg) +long get_user_pages_remote_longterm(struct task_struct *tsk, + struct mm_struct *mm, unsigned long start, + unsigned long nr_pages, unsigned int gup_flags, + struct page **pages, + struct vm_area_struct **vmas_arg) { struct vm_area_struct **vmas = vmas_arg; struct vm_area_struct *vma_prev = NULL; @@ -1157,7 +1159,9 @@ long get_user_pages_longterm(unsigned long start, unsigned long nr_pages, return -ENOMEM; } - rc = get_user_pages(start, nr_pages, gup_flags, pages, vmas); + rc = __get_user_pages_locked(tsk, mm, start, nr_pages, + pages, vmas, NULL, + gup_flags | FOLL_TOUCH | FOLL_REMOTE); for (i = 0; i < rc; i++) { struct vm_area_struct *vma = vmas[i]; @@ -1187,7 +1191,8 @@ long get_user_pages_longterm(unsigned long start, unsigned long nr_pages, kfree(vmas); return rc; } -EXPORT_SYMBOL(get_user_pages_longterm); +EXPORT_SYMBOL(get_user_pages_remote_longterm); + #endif /* CONFIG_FS_DAX */ /** -- 2.7.4