mm/gup: Switch all callers of get_user_pages() to not pass tsk/mm

We will soon modify the vanilla get_user_pages() so it can no
longer be used on mm/tasks other than 'current/current->mm',
which is by far the most common way it is called.  For now,
we allow the old-style calls, but warn when they are used.
(implemented in previous patch)

This patch switches all callers of:

	get_user_pages()
	get_user_pages_unlocked()
	get_user_pages_locked()

to stop passing tsk/mm so they will no longer see the warnings.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: jack@suse.cz
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210156.113E9407@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

4 files changed, 9 insertions, 7 deletions

diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index 7cf2b71..381bb07 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -58,7 +58,7 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
 	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
 		vec->got_ref = true;
 		vec->is_pfns = false;
-		ret = get_user_pages_locked(current, mm, start, nr_frames,
+		ret = get_user_pages_locked(start, nr_frames,
 			write, force, (struct page **)(vec->ptrs), &locked);
 		goto out;
 	}
diff --git a/mm/gup.c b/mm/gup.c
index 8a035e0..de24ef4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -936,8 +936,10 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
 EXPORT_SYMBOL(get_user_pages_remote);
 
 /*
- * This is the same as get_user_pages_remote() for the time
- * being.
+ * 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.
  */
 long get_user_pages6(unsigned long start, unsigned long nr_pages,
 		int write, int force, struct page **pages,
diff --git a/mm/ksm.c b/mm/ksm.c
index ca6d2a0..c2013f6 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -352,7 +352,7 @@ static inline bool ksm_test_exit(struct mm_struct *mm)
 /*
  * We use break_ksm to break COW on a ksm page: it's a stripped down
  *
- *	if (get_user_pages(current, mm, addr, 1, 1, 1, &page, NULL) == 1)
+ *	if (get_user_pages(addr, 1, 1, 1, &page, NULL) == 1)
  *		put_page(page);
  *
  * but taking great care only to touch a ksm page, in a VM_MERGEABLE vma,
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4c4187c..dd0ce7f 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -844,12 +844,12 @@ static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
 	}
 }
 
-static int lookup_node(struct mm_struct *mm, unsigned long addr)
+static int lookup_node(unsigned long addr)
 {
 	struct page *p;
 	int err;
 
-	err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
+	err = get_user_pages(addr & PAGE_MASK, 1, 0, 0, &p, NULL);
 	if (err >= 0) {
 		err = page_to_nid(p);
 		put_page(p);
@@ -904,7 +904,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 
 	if (flags & MPOL_F_NODE) {
 		if (flags & MPOL_F_ADDR) {
-			err = lookup_node(mm, addr);
+			err = lookup_node(addr);
 			if (err < 0)
 				goto out;
 			*policy = err;