Remove 'type' argument from access_ok() function

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 6 deletions

diff --git a/mm/gup.c b/mm/gup.c
index 8cb68a50dbdf..6f591ccb8eca 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1813,8 +1813,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
 	len = (unsigned long) nr_pages << PAGE_SHIFT;
 	end = start + len;
 
-	if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
-					(void __user *)start, len)))
+	if (unlikely(!access_ok((void __user *)start, len)))
 		return 0;
 
 	/*
@@ -1868,8 +1867,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 	if (nr_pages <= 0)
 		return 0;
 
-	if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
-					(void __user *)start, len)))
+	if (unlikely(!access_ok((void __user *)start, len)))
 		return -EFAULT;
 
 	if (gup_fast_permitted(start, nr_pages, write)) {
diff --git a/mm/mincore.c b/mm/mincore.c
index 4985965aa20a..218099b5ed31 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -233,14 +233,14 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
 		return -EINVAL;
 
 	/* ..and we need to be passed a valid user-space range */
-	if (!access_ok(VERIFY_READ, (void __user *) start, len))
+	if (!access_ok((void __user *) start, len))
 		return -ENOMEM;
 
 	/* This also avoids any overflows on PAGE_ALIGN */
 	pages = len >> PAGE_SHIFT;
 	pages += (offset_in_page(len)) != 0;
 
-	if (!access_ok(VERIFY_WRITE, vec, pages))
+	if (!access_ok(vec, pages))
 		return -EFAULT;
 
 	tmp = (void *) __get_free_page(GFP_USER);