diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2013-05-26 17:32:23 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-05-28 09:41:11 +0200 |
| commit | 662bbcb2747c2422cf98d3d97619509379eee466 (patch) | |
| tree | d733c7257e59bde654d963cce0e26454a134d787 /COPYING | |
| parent | 114276ac0a3beb9c391a410349bd770653e185ce (diff) | |
| download | linux-662bbcb2747c2422cf98d3d97619509379eee466.tar.bz2 | |
mm, sched: Allow uaccess in atomic with pagefault_disable()
This changes might_fault() so that it does not
trigger a false positive diagnostic for e.g. the following
sequence:
spin_lock_irqsave()
pagefault_disable()
copy_to_user()
pagefault_enable()
spin_unlock_irqrestore()
In particular vhost wants to do this, to call
socket ops from under a lock.
There are 3 cases to consider:
- CONFIG_PROVE_LOCKING - might_fault is non-inline
so it's easy to move the in_atomic test to fix
up the false positive warning.
- CONFIG_DEBUG_ATOMIC_SLEEP - might_fault
is currently inline, but we are calling a
non-inline __might_sleep anyway,
so let's use the non-line version of might_fault
that does the right thing.
- !CONFIG_DEBUG_ATOMIC_SLEEP && !CONFIG_PROVE_LOCKING
__might_sleep is a nop so might_fault is a nop.
Make this explicit.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1369577426-26721-11-git-send-email-mst@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'COPYING')
0 files changed, 0 insertions, 0 deletions