lockdep: simplify check_prev_add_irq()
Peter Zijlstra [Thu, 22 Jan 2009 17:10:42 +0000 (18:10 +0100)]
Remove the manual state iteration thingy.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/lockdep.c

index 22ced8d..42dfc28 100644 (file)
@@ -1268,68 +1268,84 @@ check_usage(struct task_struct *curr, struct held_lock *prev,
                        bit_backwards, bit_forwards, irqclass);
 }
 
-static int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
-               struct held_lock *next)
+static const char *state_names[] = {
+#define LOCKDEP_STATE(__STATE) \
+       STR(__STATE),
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static const char *state_rnames[] = {
+#define LOCKDEP_STATE(__STATE) \
+       STR(__STATE)"-READ",
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline const char *state_name(enum lock_usage_bit bit)
 {
-       /*
-        * Prove that the new dependency does not connect a hardirq-safe
-        * lock with a hardirq-unsafe lock - to achieve this we search
-        * the backwards-subgraph starting at <prev>, and the
-        * forwards-subgraph starting at <next>:
-        */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
-                                       LOCK_ENABLED_HARDIRQ, "hard"))
-               return 0;
+       return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
+}
 
+static int exclusive_bit(int new_bit)
+{
        /*
-        * Prove that the new dependency does not connect a hardirq-safe-read
-        * lock with a hardirq-unsafe lock - to achieve this we search
-        * the backwards-subgraph starting at <prev>, and the
-        * forwards-subgraph starting at <next>:
+        * USED_IN
+        * USED_IN_READ
+        * ENABLED
+        * ENABLED_READ
+        *
+        * bit 0 - write/read
+        * bit 1 - used_in/enabled
+        * bit 2+  state
         */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
-                                       LOCK_ENABLED_HARDIRQ, "hard-read"))
-               return 0;
+
+       int state = new_bit & ~3;
+       int dir = new_bit & 2;
 
        /*
-        * Prove that the new dependency does not connect a softirq-safe
-        * lock with a softirq-unsafe lock - to achieve this we search
-        * the backwards-subgraph starting at <prev>, and the
-        * forwards-subgraph starting at <next>:
+        * keep state, bit flip the direction and strip read.
         */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
-                                       LOCK_ENABLED_SOFTIRQ, "soft"))
-               return 0;
+       return state | (dir ^ 2);
+}
+
+static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
+                          struct held_lock *next, enum lock_usage_bit bit)
+{
        /*
-        * Prove that the new dependency does not connect a softirq-safe-read
-        * lock with a softirq-unsafe lock - to achieve this we search
+        * Prove that the new dependency does not connect a hardirq-safe
+        * lock with a hardirq-unsafe lock - to achieve this we search
         * the backwards-subgraph starting at <prev>, and the
         * forwards-subgraph starting at <next>:
         */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
-                                       LOCK_ENABLED_SOFTIRQ, "soft"))
+       if (!check_usage(curr, prev, next, bit,
+                          exclusive_bit(bit), state_name(bit)))
                return 0;
 
+       bit++; /* _READ */
+
        /*
-        * Prove that the new dependency does not connect a reclaim-fs-safe
-        * lock with a reclaim-fs-unsafe lock - to achieve this we search
+        * Prove that the new dependency does not connect a hardirq-safe-read
+        * lock with a hardirq-unsafe lock - to achieve this we search
         * the backwards-subgraph starting at <prev>, and the
         * forwards-subgraph starting at <next>:
         */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_RECLAIM_FS,
-                                       LOCK_ENABLED_RECLAIM_FS, "reclaim-fs"))
+       if (!check_usage(curr, prev, next, bit,
+                          exclusive_bit(bit), state_name(bit)))
                return 0;
 
-       /*
-        * Prove that the new dependency does not connect a reclaim-fs-safe-read
-        * lock with a reclaim-fs-unsafe lock - to achieve this we search
-        * the backwards-subgraph starting at <prev>, and the
-        * forwards-subgraph starting at <next>:
-        */
-       if (!check_usage(curr, prev, next, LOCK_USED_IN_RECLAIM_FS_READ,
-                                       LOCK_ENABLED_RECLAIM_FS, "reclaim-fs-read"))
+       return 1;
+}
+
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+               struct held_lock *next)
+{
+#define LOCKDEP_STATE(__STATE)                                         \
+       if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
                return 0;
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
 
        return 1;
 }
@@ -1984,30 +2000,6 @@ static int RECLAIM_FS_verbose(struct lock_class *class)
 
 #define STRICT_READ_CHECKS     1
 
-static const char *state_names[] = {
-#define LOCKDEP_STATE(__STATE) \
-       STR(__STATE),
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static inline const char *state_name(enum lock_usage_bit bit)
-{
-       return state_names[bit >> 2];
-}
-
-static const char *state_rnames[] = {
-#define LOCKDEP_STATE(__STATE) \
-       STR(__STATE)"-READ",
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
-static inline const char *state_rname(enum lock_usage_bit bit)
-{
-       return state_rnames[bit >> 2];
-}
-
 static int (*state_verbose_f[])(struct lock_class *class) = {
 #define LOCKDEP_STATE(__STATE) \
        __STATE##_verbose,
@@ -2021,37 +2013,12 @@ static inline int state_verbose(enum lock_usage_bit bit,
        return state_verbose_f[bit >> 2](class);
 }
 
-static int exclusive_bit(int new_bit)
-{
-       /*
-        * USED_IN
-        * USED_IN_READ
-        * ENABLED
-        * ENABLED_READ
-        *
-        * bit 0 - write/read
-        * bit 1 - used_in/enabled
-        * bit 2+  state
-        */
-
-       int state = new_bit & ~3;
-       int dir = new_bit & 2;
-
-       /*
-        * keep state, bit flip the direction and strip read.
-        */
-       return state | (dir ^ 2);
-}
-
 typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
                             enum lock_usage_bit bit, const char *name);
 
 static int
 mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
 {
-       const char *name = state_name(new_bit);
-       const char *rname = state_rname(new_bit);
-
        int excl_bit = exclusive_bit(new_bit);
        int read = new_bit & 1;
        int dir = new_bit & 2;
@@ -2078,7 +2045,7 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
         * states.
         */
        if ((!read || !dir || STRICT_READ_CHECKS) &&
-                       !usage(curr, this, excl_bit, name))
+                       !usage(curr, this, excl_bit, state_name(new_bit)))
                return 0;
 
        /*
@@ -2089,7 +2056,8 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
                        return 0;
 
                if (STRICT_READ_CHECKS &&
-                               !usage(curr, this, excl_bit + 1, rname))
+                       !usage(curr, this, excl_bit + 1,
+                               state_name(new_bit + 1)))
                        return 0;
        }