From 5b56d49fc31dbb0487e14ead790fc81ca9fb2c99 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Wed, 14 Dec 2016 15:06:52 -0800 Subject: mm: add locked parameter to get_user_pages_remote() Patch series "mm: unexport __get_user_pages_unlocked()". This patch series continues the cleanup of get_user_pages*() functions taking advantage of the fact we can now pass gup_flags as we please. It firstly adds an additional 'locked' parameter to get_user_pages_remote() to allow for its callers to utilise VM_FAULT_RETRY functionality. This is necessary as the invocation of __get_user_pages_unlocked() in process_vm_rw_single_vec() makes use of this and no other existing higher level function would allow it to do so. Secondly existing callers of __get_user_pages_unlocked() are replaced with the appropriate higher-level replacement - get_user_pages_unlocked() if the current task and memory descriptor are referenced, or get_user_pages_remote() if other task/memory descriptors are referenced (having acquiring mmap_sem.) This patch (of 2): Add a int *locked parameter to get_user_pages_remote() to allow VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked(). Taking into account the previous adjustments to get_user_pages*() functions allowing for the passing of gup_flags, we are now in a position where __get_user_pages_unlocked() need only be exported for his ability to allow VM_FAULT_RETRY behaviour, this adjustment allows us to subsequently unexport __get_user_pages_unlocked() as well as allowing for future flexibility in the use of get_user_pages_remote(). [sfr@canb.auug.org.au: merge fix for get_user_pages_remote API change] Link: http://lkml.kernel.org/r/20161122210511.024ec341@canb.auug.org.au Link: http://lkml.kernel.org/r/20161027095141.2569-2-lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Acked-by: Michal Hocko Cc: Jan Kara Cc: Hugh Dickins Cc: Dave Hansen Cc: Rik van Riel Cc: Mel Gorman Cc: Paolo Bonzini Cc: Radim Krcmar Signed-off-by: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/gup.c | 12 ++++++++---- mm/memory.c | 2 +- 2 files changed, 9 insertions(+), 5 deletions(-) (limited to 'mm') diff --git a/mm/gup.c b/mm/gup.c index e50178c..b64c907 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -917,6 +917,9 @@ EXPORT_SYMBOL(get_user_pages_unlocked); * only intends to ensure the pages are faulted in. * @vmas: array of pointers to vmas corresponding to each page. * Or NULL if the caller does not require them. + * @locked: pointer to lock flag indicating whether lock is held and + * subsequently whether VM_FAULT_RETRY functionality can be + * utilised. Lock must initially be held. * * Returns number of pages pinned. This may be fewer than the number * requested. If nr_pages is 0 or negative, returns 0. If no pages @@ -960,10 +963,10 @@ EXPORT_SYMBOL(get_user_pages_unlocked); long get_user_pages_remote(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) + struct vm_area_struct **vmas, int *locked) { return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas, - NULL, false, + locked, true, gup_flags | FOLL_TOUCH | FOLL_REMOTE); } EXPORT_SYMBOL(get_user_pages_remote); @@ -971,8 +974,9 @@ EXPORT_SYMBOL(get_user_pages_remote); /* * This is the same as get_user_pages_remote(), just with a * less-flexible calling convention where we assume that the task - * and mm being operated on are the current task's. We also - * obviously don't pass FOLL_REMOTE in here. + * and mm being operated on are the current task's and don't allow + * passing of a locked parameter. We also obviously don't pass + * FOLL_REMOTE in here. */ long get_user_pages(unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, diff --git a/mm/memory.c b/mm/memory.c index c264f7c..3a6a123 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3919,7 +3919,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, struct page *page = NULL; ret = get_user_pages_remote(tsk, mm, addr, 1, - gup_flags, &page, &vma); + gup_flags, &page, &vma, NULL); if (ret <= 0) { #ifndef CONFIG_HAVE_IOREMAP_PROT break; -- cgit v1.1