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Date: Thu, 13 Oct 2016 01:20:14 +0100 From: Lorenzo Stoakes <lstoakes@...il.com> To: linux-mm@...ck.org Cc: Linus Torvalds <torvalds@...ux-foundation.org>, Jan Kara <jack@...e.cz>, Hugh Dickins <hughd@...gle.com>, Dave Hansen <dave.hansen@...ux.intel.com>, Rik van Riel <riel@...hat.com>, Mel Gorman <mgorman@...hsingularity.net>, Andrew Morton <akpm@...ux-foundation.org>, adi-buildroot-devel@...ts.sourceforge.net, ceph-devel@...r.kernel.org, dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org, kvm@...r.kernel.org, linux-alpha@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-cris-kernel@...s.com, linux-fbdev@...r.kernel.org, linux-fsdevel@...r.kernel.org, linux-ia64@...r.kernel.org, linux-kernel@...r.kernel.org, linux-media@...r.kernel.org, linux-mips@...ux-mips.org, linux-rdma@...r.kernel.org, linux-s390@...r.kernel.org, linux-samsung-soc@...r.kernel.org, linux-scsi@...r.kernel.org, linux-security-module@...r.kernel.org, linux-sh@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org, netdev@...r.kernel.org, sparclinux@...r.kernel.org, x86@...nel.org, Lorenzo Stoakes <lstoakes@...il.com> Subject: [PATCH 04/10] mm: replace get_user_pages_locked() write/force parameters with gup_flags This patch removes the write and force parameters from get_user_pages_locked() and replaces them with a gup_flags parameter to make the use of FOLL_FORCE explicit in callers as use of this flag can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes <lstoakes@...il.com> --- include/linux/mm.h | 2 +- mm/frame_vector.c | 8 +++++++- mm/gup.c | 12 +++--------- mm/nommu.c | 5 ++++- 4 files changed, 15 insertions(+), 12 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 6adc4bc..27ab538 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1282,7 +1282,7 @@ long get_user_pages(unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages, struct vm_area_struct **vmas); long get_user_pages_locked(unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, int *locked); + unsigned int gup_flags, struct page **pages, int *locked); long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags); diff --git a/mm/frame_vector.c b/mm/frame_vector.c index 381bb07..81b6749 100644 --- a/mm/frame_vector.c +++ b/mm/frame_vector.c @@ -41,10 +41,16 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, int ret = 0; int err; int locked; + unsigned int gup_flags = 0; if (nr_frames == 0) return 0; + if (write) + gup_flags |= FOLL_WRITE; + if (force) + gup_flags |= FOLL_FORCE; + if (WARN_ON_ONCE(nr_frames > vec->nr_allocated)) nr_frames = vec->nr_allocated; @@ -59,7 +65,7 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, vec->got_ref = true; vec->is_pfns = false; ret = get_user_pages_locked(start, nr_frames, - write, force, (struct page **)(vec->ptrs), &locked); + gup_flags, (struct page **)(vec->ptrs), &locked); goto out; } diff --git a/mm/gup.c b/mm/gup.c index cfcb014..7a0d033 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -838,18 +838,12 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, * up_read(&mm->mmap_sem); */ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, + unsigned int gup_flags, struct page **pages, int *locked) { - unsigned int flags = FOLL_TOUCH; - - if (write) - flags |= FOLL_WRITE; - if (force) - flags |= FOLL_FORCE; - return __get_user_pages_locked(current, current->mm, start, nr_pages, - pages, NULL, locked, true, flags); + pages, NULL, locked, true, + gup_flags | FOLL_TOUCH); } EXPORT_SYMBOL(get_user_pages_locked); diff --git a/mm/nommu.c b/mm/nommu.c index 7e27add..842cfdd 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -176,9 +176,12 @@ long get_user_pages(unsigned long start, unsigned long nr_pages, EXPORT_SYMBOL(get_user_pages); long get_user_pages_locked(unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, + unsigned int gup_flags, struct page **pages, int *locked) { + int write = gup_flags & FOLL_WRITE; + int force = gup_flags & FOLL_FORCE; + return get_user_pages(start, nr_pages, write, force, pages, NULL); } EXPORT_SYMBOL(get_user_pages_locked); -- 2.10.0
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