diff options
| author | Suren Baghdasaryan <surenb@google.com> | 2023-06-30 14:19:57 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-08-24 16:20:17 -0700 |
| commit | 29a22b9e08d70d6c9b075c12c47b6e895cb65cf0 (patch) | |
| tree | 0eaa40e38ee6729a4ef2102ef4df0010db69f5de /mm | |
| parent | 1235ccd05b6dd6970ff50baea99aa994023fbc4a (diff) | |
mm: handle userfaults under VMA lock
Enable handle_userfault to operate under VMA lock by releasing VMA lock
instead of mmap_lock and retrying. Note that FAULT_FLAG_RETRY_NOWAIT
should never be used when handling faults under per-VMA lock protection
because that would break the assumption that lock is dropped on retry.
[surenb@google.com: fix a lockdep issue in vma_assert_write_locked]
Link: https://lkml.kernel.org/r/20230712195652.969194-1-surenb@google.com
Link: https://lkml.kernel.org/r/20230630211957.1341547-7-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hillf Danton <hdanton@sina.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michel Lespinasse <michel@lespinasse.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 9 |
1 files changed, 1 insertions, 8 deletions
diff --git a/mm/memory.c b/mm/memory.c index 5748a41c164c..2c6f45d18b73 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5471,14 +5471,7 @@ retry: * concurrent mremap() with MREMAP_DONTUNMAP could dissociate the VMA * from its anon_vma. */ - if (vma_is_anonymous(vma) && !vma->anon_vma) - goto inval_end_read; - - /* - * Due to the possibility of userfault handler dropping mmap_lock, avoid - * it for now and fall back to page fault handling under mmap_lock. - */ - if (userfaultfd_armed(vma)) + if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) goto inval_end_read; /* Check since vm_start/vm_end might change before we lock the VMA */ |