1. 31 May, 2023 1 commit
    • David Howells's avatar
      mm: Don't pin ZERO_PAGE in pin_user_pages() · c8070b78
      David Howells authored
      Make pin_user_pages*() leave a ZERO_PAGE unpinned if it extracts a pointer
      to it from the page tables and make unpin_user_page*() correspondingly
      ignore a ZERO_PAGE when unpinning.  We don't want to risk overrunning a
      zero page's refcount as we're only allowed ~2 million pins on it -
      something that userspace can conceivably trigger.
      
      Add a pair of functions to test whether a page or a folio is a ZERO_PAGE.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      cc: Christoph Hellwig <hch@infradead.org>
      cc: David Hildenbrand <david@redhat.com>
      cc: Lorenzo Stoakes <lstoakes@gmail.com>
      cc: Andrew Morton <akpm@linux-foundation.org>
      cc: Jens Axboe <axboe@kernel.dk>
      cc: Al Viro <viro@zeniv.linux.org.uk>
      cc: Matthew Wilcox <willy@infradead.org>
      cc: Jan Kara <jack@suse.cz>
      cc: Jeff Layton <jlayton@kernel.org>
      cc: Jason Gunthorpe <jgg@nvidia.com>
      cc: Logan Gunthorpe <logang@deltatee.com>
      cc: Hillf Danton <hdanton@sina.com>
      cc: Christian Brauner <brauner@kernel.org>
      cc: Linus Torvalds <torvalds@linux-foundation.org>
      cc: linux-fsdevel@vger.kernel.org
      cc: linux-block@vger.kernel.org
      cc: linux-kernel@vger.kernel.org
      cc: linux-mm@kvack.org
      Reviewed-by: default avatarLorenzo Stoakes <lstoakes@gmail.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
      Link: https://lore.kernel.org/r/20230526214142.958751-2-dhowells@redhat.comSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
      c8070b78
  2. 30 May, 2023 4 commits
  3. 24 May, 2023 35 commits