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Subject[PATCH v7 0/2] lockdep: add support for queued rwlock
Date
v6->v7:
- Add recursive read-lock with interrupt test in locking-selftest.c.

v5->v6:
- Unconditionally disallow the use of recursive read-lock in process
context.
- Promote read state 3 to 2 when in interrupt context instead of
doing additional check in check_deadlock().
- Fix some comments in locking-selftest.c.

v4->v5:
- Add patch 2 to update the locking selftest code to handle recursive
read_lock correctly. Patch 1 has no change.

v3->v4:
- Document the new read state and move the conditional compilation code
to lockdep.h.

v2->v3:
- Add a new read mode (3) for rwlock (used in
lock_acquire_shared_cond_recursive()) to avoid conflict with other
use cases of lock_acquire_shared_recursive().

v1->v2:
- Use less conditional & make it easier to read

With the merging of qrwlock into 3.16, it was found that the btrfs
filesystem hanged readily. A fix was devised and merged into rc2 and
the use of recursive read_lock call was part of the problem.

This patch series addes code to the lockdep subsystem to catch this
kind of recursive read_lock calls in kernel code. It also updates
the locking selftest to handle recursive read_lock correctly so that
it won't complain about test failures.

Waiman Long (2):
locking/lockdep: Restrict the use of recursive read_lock() with
qrwlock
locking/selftest: Support queued rwlock

include/linux/lockdep.h | 10 +++++++-
kernel/locking/lockdep.c | 6 +++++
lib/locking-selftest.c | 56 ++++++++++++++++++++++++++++++++++++++++-----
3 files changed, 64 insertions(+), 8 deletions(-)



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