mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-01-19 20:05:08 +00:00
b7cb382190
This effectively reverts commit 16c243e99d33 ("udmabuf: Add support for
mapping hugepages (v4)"). Recently, Junxiao Chang found a BUG with page
map counting as described here [1]. This issue pointed out that the
udmabuf driver was making direct use of subpages of hugetlb pages. This
is not a good idea, and no other mm code attempts such use. In addition
to the mapcount issue, this also causes issues with hugetlb vmemmap
optimization and page poisoning.
For now, remove hugetlb support.
If udmabuf wants to be used on hugetlb mappings, it should be changed to
only use complete hugetlb pages. This will require different alignment
and size requirements on the UDMABUF_CREATE API.
[1] https://lore.kernel.org/linux-mm/20230512072036.1027784-1-junxiao.chang@intel.com/
Link: https://lkml.kernel.org/r/20230608204927.88711-1-mike.kravetz@oracle.com
Fixes: 16c243e99d33 ("udmabuf: Add support for mapping hugepages (v4)")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Junxiao Chang <junxiao.chang@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.