On 23.01.23 13:44, Jason Gunthorpe wrote:
On Mon, Jan 23, 2023 at 12:35:28PM +0100, David Hildenbrand wrote:
On 17.01.23 16:58, Jason Gunthorpe wrote:
Now that NULL locked doesn't have a special meaning we can just make it
non-NULL in all cases and remove the special tests.
get_user_pages() and pin_user_pages() can safely pass in a locked = 1
get_user_pages_remote) and pin_user_pages_remote() can swap in a local
variable for locked if NULL is passed.
Remove all the NULL checks.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
mm/gup.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
... doesn't really look like a real cleanup. Especially with the
2 files changed, 20 insertions(+), 12 deletions(-)
on the previous patch and a new internal flag ....
What's the benefit?
There are all kinds of unnecessary branches on the faster paths,
inside loops, etc to check for NULL when all we really needed was a
single bit flag.
... call me skeptical that this optimization matters in practice ;)
It isalos much clearer to understand that a FOLL flag changes the
behavior of how GUP works rather than some weirdo NULL argument.
The whole "locked" parameter handling is weird. I don't think adding a
new FOLL_ internal flag on top particularly improves the situation ...
at least before, the logic around that "locked" parameter handling was
self-contained. Self-contained weirdness.
--
Thanks,
David / dhildenb
