[PATCH] spinlock consolidation

This patch (written by me and also containing many suggestions of Arjan van
de Ven) does a major cleanup of the spinlock code.  It does the following
things:

 - consolidates and enhances the spinlock/rwlock debugging code

 - simplifies the asm/spinlock.h files

 - encapsulates the raw spinlock type and moves generic spinlock
   features (such as ->break_lock) into the generic code.

 - cleans up the spinlock code hierarchy to get rid of the spaghetti.

Most notably there's now only a single variant of the debugging code,
located in lib/spinlock_debug.c.  (previously we had one SMP debugging
variant per architecture, plus a separate generic one for UP builds)

Also, i've enhanced the rwlock debugging facility, it will now track
write-owners.  There is new spinlock-owner/CPU-tracking on SMP builds too.
All locks have lockup detection now, which will work for both soft and hard
spin/rwlock lockups.

The arch-level include files now only contain the minimally necessary
subset of the spinlock code - all the rest that can be generalized now
lives in the generic headers:

 include/asm-i386/spinlock_types.h       |   16
 include/asm-x86_64/spinlock_types.h     |   16

I have also split up the various spinlock variants into separate files,
making it easier to see which does what. The new layout is:

   SMP                         |  UP
   ----------------------------|-----------------------------------
   asm/spinlock_types_smp.h    |  linux/spinlock_types_up.h
   linux/spinlock_types.h      |  linux/spinlock_types.h
   asm/spinlock_smp.h          |  linux/spinlock_up.h
   linux/spinlock_api_smp.h    |  linux/spinlock_api_up.h
   linux/spinlock.h            |  linux/spinlock.h

/*
 * here's the role of the various spinlock/rwlock related include files:
 *
 * on SMP builds:
 *
 *  asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
 *                        initializers
 *
 *  linux/spinlock_types.h:
 *                        defines the generic type and initializers
 *
 *  asm/spinlock.h:       contains the __raw_spin_*()/etc. lowlevel
 *                        implementations, mostly inline assembly code
 *
 *   (also included on UP-debug builds:)
 *
 *  linux/spinlock_api_smp.h:
 *                        contains the prototypes for the _spin_*() APIs.
 *
 *  linux/spinlock.h:     builds the final spin_*() APIs.
 *
 * on UP builds:
 *
 *  linux/spinlock_type_up.h:
 *                        contains the generic, simplified UP spinlock type.
 *                        (which is an empty structure on non-debug builds)
 *
 *  linux/spinlock_types.h:
 *                        defines the generic type and initializers
 *
 *  linux/spinlock_up.h:
 *                        contains the __raw_spin_*()/etc. version of UP
 *                        builds. (which are NOPs on non-debug, non-preempt
 *                        builds)
 *
 *   (included on UP-non-debug builds:)
 *
 *  linux/spinlock_api_up.h:
 *                        builds the _spin_*() APIs.
 *
 *  linux/spinlock.h:     builds the final spin_*() APIs.
 */

All SMP and UP architectures are converted by this patch.

arm, i386, ia64, ppc, ppc64, s390/s390x, x64 was build-tested via
crosscompilers.  m32r, mips, sh, sparc, have not been tested yet, but should
be mostly fine.

From: Grant Grundler <grundler@parisc-linux.org>

  Booted and lightly tested on a500-44 (64-bit, SMP kernel, dual CPU).
  Builds 32-bit SMP kernel (not booted or tested).  I did not try to build
  non-SMP kernels.  That should be trivial to fix up later if necessary.

  I converted bit ops atomic_hash lock to raw_spinlock_t.  Doing so avoids
  some ugly nesting of linux/*.h and asm/*.h files.  Those particular locks
  are well tested and contained entirely inside arch specific code.  I do NOT
  expect any new issues to arise with them.

 If someone does ever need to use debug/metrics with them, then they will
  need to unravel this hairball between spinlocks, atomic ops, and bit ops
  that exist only because parisc has exactly one atomic instruction: LDCW
  (load and clear word).

From: "Luck, Tony" <tony.luck@intel.com>

   ia64 fix

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjanv@infradead.org>
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Cc: Matthew Wilcox <willy@debian.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se>
Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 42 insertions, 138 deletions

diff --git a/include/asm-sparc64/spinlock.h b/include/asm-sparc64/spinlock.h
index a02c4370eb42..ec85d12d73b9 100644
--- a/include/asm-sparc64/spinlock.h
+++ b/include/asm-sparc64/spinlock.h
@@ -29,24 +29,13 @@
  * must be pre-V9 branches.
  */
 
-#ifndef CONFIG_DEBUG_SPINLOCK
+#define __raw_spin_is_locked(lp)        ((lp)->lock != 0)
 
-typedef struct {
-        volatile unsigned char lock;
-#ifdef CONFIG_PREEMPT
-        unsigned int break_lock;
-#endif
-} spinlock_t;
-#define SPIN_LOCK_UNLOCKED      (spinlock_t) {0,}
+#define __raw_spin_unlock_wait(lp)      \
+        do {    rmb();                  \
+        } while((lp)->lock)
 
-#define spin_lock_init(lp)      do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
-#define spin_is_locked(lp)  ((lp)->lock != 0)
-
-#define spin_unlock_wait(lp)    \
-do {    rmb();                  \
-} while((lp)->lock)
-
-static inline void _raw_spin_lock(spinlock_t *lock)
+static inline void __raw_spin_lock(raw_spinlock_t *lock)
 {
         unsigned long tmp;
 
@@ -67,7 +56,7 @@ static inline void _raw_spin_lock(spinlock_t *lock)
         : "memory");
 }
 
-static inline int _raw_spin_trylock(spinlock_t *lock)
+static inline int __raw_spin_trylock(raw_spinlock_t *lock)
 {
         unsigned long result;
 
@@ -81,7 +70,7 @@ static inline int _raw_spin_trylock(spinlock_t *lock)
         return (result == 0UL);
 }
 
-static inline void _raw_spin_unlock(spinlock_t *lock)
+static inline void __raw_spin_unlock(raw_spinlock_t *lock)
 {
         __asm__ __volatile__(
 "       membar          #StoreStore | #LoadStore\n"
@@ -91,7 +80,7 @@ static inline void _raw_spin_unlock(spinlock_t *lock)
         : "memory");
 }
 
-static inline void _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags)
+static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
 {
         unsigned long tmp1, tmp2;
 
@@ -115,51 +104,9 @@ static inline void _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags)
         : "memory");
 }
 
-#else /* !(CONFIG_DEBUG_SPINLOCK) */
-
-typedef struct {
-        volatile unsigned char lock;
-        unsigned int owner_pc, owner_cpu;
-#ifdef CONFIG_PREEMPT
-        unsigned int break_lock;
-#endif
-} spinlock_t;
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
-#define spin_lock_init(lp)      do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
-#define spin_is_locked(__lock)  ((__lock)->lock != 0)
-#define spin_unlock_wait(__lock)        \
-do { \
-        rmb(); \
-} while((__lock)->lock)
-
-extern void _do_spin_lock(spinlock_t *lock, char *str, unsigned long caller);
-extern void _do_spin_unlock(spinlock_t *lock);
-extern int _do_spin_trylock(spinlock_t *lock, unsigned long caller);
-
-#define _raw_spin_trylock(lp)   \
-        _do_spin_trylock(lp, (unsigned long) __builtin_return_address(0))
-#define _raw_spin_lock(lock)    \
-        _do_spin_lock(lock, "spin_lock", \
-                      (unsigned long) __builtin_return_address(0))
-#define _raw_spin_unlock(lock)  _do_spin_unlock(lock)
-#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
-
-#endif /* CONFIG_DEBUG_SPINLOCK */
-
 /* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
 
-#ifndef CONFIG_DEBUG_SPINLOCK
-
-typedef struct {
-        volatile unsigned int lock;
-#ifdef CONFIG_PREEMPT
-        unsigned int break_lock;
-#endif
-} rwlock_t;
-#define RW_LOCK_UNLOCKED        (rwlock_t) {0,}
-#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
-
-static void inline __read_lock(rwlock_t *lock)
+static void inline __read_lock(raw_rwlock_t *lock)
 {
         unsigned long tmp1, tmp2;
 
@@ -184,7 +131,7 @@ static void inline __read_lock(rwlock_t *lock)
         : "memory");
 }
 
-static void inline __read_unlock(rwlock_t *lock)
+static void inline __read_unlock(raw_rwlock_t *lock)
 {
         unsigned long tmp1, tmp2;
 
@@ -201,7 +148,7 @@ static void inline __read_unlock(rwlock_t *lock)
         : "memory");
 }
 
-static void inline __write_lock(rwlock_t *lock)
+static void inline __write_lock(raw_rwlock_t *lock)
 {
         unsigned long mask, tmp1, tmp2;
 
@@ -228,7 +175,7 @@ static void inline __write_lock(rwlock_t *lock)
         : "memory");
 }
 
-static void inline __write_unlock(rwlock_t *lock)
+static void inline __write_unlock(raw_rwlock_t *lock)
 {
         __asm__ __volatile__(
 "       membar          #LoadStore | #StoreStore\n"
@@ -238,7 +185,7 @@ static void inline __write_unlock(rwlock_t *lock)
         : "memory");
 }
 
-static int inline __write_trylock(rwlock_t *lock)
+static int inline __write_trylock(raw_rwlock_t *lock)
 {
         unsigned long mask, tmp1, tmp2, result;
 
@@ -263,78 +210,15 @@ static int inline __write_trylock(rwlock_t *lock)
         return result;
 }
 
-#define _raw_read_lock(p)       __read_lock(p)
-#define _raw_read_unlock(p)     __read_unlock(p)
-#define _raw_write_lock(p)      __write_lock(p)
-#define _raw_write_unlock(p)    __write_unlock(p)
-#define _raw_write_trylock(p)   __write_trylock(p)
-
-#else /* !(CONFIG_DEBUG_SPINLOCK) */
-
-typedef struct {
-        volatile unsigned long lock;
-        unsigned int writer_pc, writer_cpu;
-        unsigned int reader_pc[NR_CPUS];
-#ifdef CONFIG_PREEMPT
-        unsigned int break_lock;
-#endif
-} rwlock_t;
-#define RW_LOCK_UNLOCKED        (rwlock_t) { 0, 0, 0xff, { } }
-#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
-
-extern void _do_read_lock(rwlock_t *rw, char *str, unsigned long caller);
-extern void _do_read_unlock(rwlock_t *rw, char *str, unsigned long caller);
-extern void _do_write_lock(rwlock_t *rw, char *str, unsigned long caller);
-extern void _do_write_unlock(rwlock_t *rw, unsigned long caller);
-extern int _do_write_trylock(rwlock_t *rw, char *str, unsigned long caller);
-
-#define _raw_read_lock(lock) \
-do {    unsigned long flags; \
-        local_irq_save(flags); \
-        _do_read_lock(lock, "read_lock", \
-                      (unsigned long) __builtin_return_address(0)); \
-        local_irq_restore(flags); \
-} while(0)
-
-#define _raw_read_unlock(lock) \
-do {    unsigned long flags; \
-        local_irq_save(flags); \
-        _do_read_unlock(lock, "read_unlock", \
-                      (unsigned long) __builtin_return_address(0)); \
-        local_irq_restore(flags); \
-} while(0)
-
-#define _raw_write_lock(lock) \
-do {    unsigned long flags; \
-        local_irq_save(flags); \
-        _do_write_lock(lock, "write_lock", \
-                      (unsigned long) __builtin_return_address(0)); \
-        local_irq_restore(flags); \
-} while(0)
-
-#define _raw_write_unlock(lock) \
-do {    unsigned long flags; \
-        local_irq_save(flags); \
-        _do_write_unlock(lock, \
-                      (unsigned long) __builtin_return_address(0)); \
-        local_irq_restore(flags); \
-} while(0)
-
-#define _raw_write_trylock(lock) \
-({      unsigned long flags; \
-        int val; \
-        local_irq_save(flags); \
-        val = _do_write_trylock(lock, "write_trylock", \
-                                (unsigned long) __builtin_return_address(0)); \
-        local_irq_restore(flags); \
-        val; \
-})
-
-#endif /* CONFIG_DEBUG_SPINLOCK */
-
-#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
-#define read_can_lock(rw)       (!((rw)->lock & 0x80000000UL))
-#define write_can_lock(rw)      (!(rw)->lock)
+#define __raw_read_lock(p)      __read_lock(p)
+#define __raw_read_unlock(p)    __read_unlock(p)
+#define __raw_write_lock(p)     __write_lock(p)
+#define __raw_write_unlock(p)   __write_unlock(p)
+#define __raw_write_trylock(p)  __write_trylock(p)
+
+#define __raw_read_trylock(lock)        generic__raw_read_trylock(lock)
+#define __raw_read_can_lock(rw)         (!((rw)->lock & 0x80000000UL))
+#define __raw_write_can_lock(rw)        (!(rw)->lock)
 
 #endif /* !(__ASSEMBLY__) */
 
diff --git a/include/asm-sparc64/spinlock_types.h b/include/asm-sparc64/spinlock_types.h
new file mode 100644
index 000000000000..e128112a0d7c
--- /dev/null
+++ b/include/asm-sparc64/spinlock_types.h
@@ -0,0 +1,20 @@
+#ifndef __SPARC64_SPINLOCK_TYPES_H
+#define __SPARC64_SPINLOCK_TYPES_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+# error "please don't include this file directly"
+#endif
+
+typedef struct {
+        volatile unsigned char lock;
+} raw_spinlock_t;
+
+#define __RAW_SPIN_LOCK_UNLOCKED        { 0 }
+
+typedef struct {
+        volatile unsigned int lock;
+} raw_rwlock_t;
+
+#define __RAW_RW_LOCK_UNLOCKED          { 0 }
+
+#endif