On Thu, Sep 03, 2020 at 05:43:25PM +0200, Christophe Leroy wrote:

Le 03/09/2020 à 16:22, Christoph Hellwig a écrit :

quoted

Stop providing the possibility to override the address space using
set_fs() now that there is no need for that any more.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---

quoted

  -static inline int __access_ok(unsigned long addr, unsigned long size,
-			mm_segment_t seg)
+static inline bool __access_ok(unsigned long addr, unsigned long size)
  {
-	if (addr > seg.seg)
-		return 0;
-	return (size == 0 || size - 1 <= seg.seg - addr);
+	if (addr >= TASK_SIZE_MAX)
+		return false;
+	return size == 0 || size <= TASK_SIZE_MAX - addr;
  }

You don't need to test size == 0 anymore. It used to be necessary because 
of the 'size - 1', as size is unsigned.

Now you can directly do

	return size <= TASK_SIZE_MAX - addr;

If size is 0, this will always be true (because you already know that addr 
is not >= TASK_SIZE_MAX

True.  What do you think of Linus' comment about always using the
ppc32 version on ppc64 as well with this?