From 1b963c81b14509e330e0fe3218b645ece2738dc5 Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Fri, 11 Jan 2013 14:31:56 -0800 Subject: lockdep, rwsem: provide down_write_nest_lock() down_write_nest_lock() provides a means to annotate locking scenario where an outer lock is guaranteed to serialize the order nested locks are being acquired. This is analogoue to already existing mutex_lock_nest_lock() and spin_lock_nest_lock(). Signed-off-by: Jiri Kosina Cc: Rik van Riel Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Mel Gorman Tested-by: Sedat Dilek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/lockdep.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/lockdep.h') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 00e46376e28f..2bca44b0893c 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -524,14 +524,17 @@ static inline void print_irqtrace_events(struct task_struct *curr) #ifdef CONFIG_DEBUG_LOCK_ALLOC # ifdef CONFIG_PROVE_LOCKING # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) +# define rwsem_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i) # else # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) +# define rwsem_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i) # endif # define rwsem_release(l, n, i) lock_release(l, n, i) #else # define rwsem_acquire(l, s, t, i) do { } while (0) +# define rwsem_acquire_nest(l, s, t, n, i) do { } while (0) # define rwsem_acquire_read(l, s, t, i) do { } while (0) # define rwsem_release(l, n, i) do { } while (0) #endif -- cgit v1.2.3 From 5cd3f5affad2109fd1458aab3f6216f2181e26ea Mon Sep 17 00:00:00 2001 From: Paul Bolle Date: Thu, 24 Jan 2013 21:53:17 +0100 Subject: lockdep: Silence warning if CONFIG_LOCKDEP isn't set MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since commit c9a4962881929df7f1ef6e63e1b9da304faca4dd ("nfsd: make client_lock per net") compiling nfs4state.o without CONFIG_LOCKDEP set, triggers this GCC warning: fs/nfsd/nfs4state.c: In function ‘free_client’: fs/nfsd/nfs4state.c:1051:19: warning: unused variable ‘nn’ [-Wunused-variable] The cause of that warning is that lockdep_assert_held() compiles away if CONFIG_LOCKDEP is not set. Silence this warning by using the argument to lockdep_assert_held() as a nop if CONFIG_LOCKDEP is not set. Signed-off-by: Paul Bolle Cc: Peter Zijlstra Cc: Stanislav Kinsbursky Cc: J. Bruce Fields Link: http://lkml.kernel.org/r/1359060797.1325.33.camel@x61.thuisdomein Signed-off-by: Ingo Molnar -- include/linux/lockdep.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- include/linux/lockdep.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/lockdep.h') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 2bca44b0893c..f05631effc73 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -410,7 +410,7 @@ struct lock_class_key { }; #define lockdep_depth(tsk) (0) -#define lockdep_assert_held(l) do { } while (0) +#define lockdep_assert_held(l) do { (void)(l); } while (0) #define lockdep_recursing(tsk) (0) -- cgit v1.2.3 From b1ae345d971664f70cfdc293029c40ccfb093591 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 21 Feb 2013 16:42:47 -0800 Subject: lockdep: make lockdep_assert_held() not have a return value I recently made the mistake of writing: foo = lockdep_dereference_protected(..., lockdep_assert_held(...)); which is clearly bogus. If lockdep is disabled in the config this would cause a compile failure, if it is enabled then it compiles and causes a puzzling warning about dereferencing without the correct protection. Wrap the macro in "do { ... } while (0)" to also fail compile for this when lockdep is enabled. Signed-off-by: Johannes Berg Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/lockdep.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/linux/lockdep.h') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 2bca44b0893c..bfe88c4aa251 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -359,7 +359,9 @@ extern void lockdep_trace_alloc(gfp_t mask); #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) -#define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l)) +#define lockdep_assert_held(l) do { \ + WARN_ON(debug_locks && !lockdep_is_held(l)); \ + } while (0) #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion) -- cgit v1.2.3