svn commit: r314965 - head/sys/compat/linuxkpi/common/include/linux
Hans Petter Selasky
hselasky at FreeBSD.org
Thu Mar 9 17:01:01 UTC 2017
Author: hselasky
Date: Thu Mar 9 17:01:00 2017
New Revision: 314965
URL: https://svnweb.freebsd.org/changeset/base/314965
Log:
Cleanup the LinuxKPI mutex wrappers.
Add support for using mutexes during KDB and shutdown. This is also
required for doing mode-switching during panic for drm-next.
Add new mutex functions mutex_init_witness() and mutex_destroy()
allowing LinuxKPI mutexes to be tracked by witness.
Declare mutex_is_locked() and mutex_is_owned() like inline functions
to get cleaner warnings. These functions are used inside WARN_ON()
statements which might look a bit odd if these functions get fully
expanded.
Give mutexes better debug names through the mutex_name() macro when
WITNESS_ALL is defined. The mutex_name() macro can prefix parts of the
filename and line number before the mutex name.
MFC after: 1 week
Sponsored by: Mellanox Technologies
Modified:
head/sys/compat/linuxkpi/common/include/linux/mutex.h
Modified: head/sys/compat/linuxkpi/common/include/linux/mutex.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/linux/mutex.h Thu Mar 9 16:34:55 2017 (r314964)
+++ head/sys/compat/linuxkpi/common/include/linux/mutex.h Thu Mar 9 17:01:00 2017 (r314965)
@@ -2,7 +2,7 @@
* Copyright (c) 2010 Isilon Systems, Inc.
* Copyright (c) 2010 iX Systems, Inc.
* Copyright (c) 2010 Panasas, Inc.
- * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
+ * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -32,6 +32,7 @@
#define _LINUX_MUTEX_H_
#include <sys/param.h>
+#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/sx.h>
@@ -41,24 +42,90 @@ typedef struct mutex {
struct sx sx;
} mutex_t;
-#define mutex_lock(_m) sx_xlock(&(_m)->sx)
+/*
+ * By defining CONFIG_NO_MUTEX_SKIP LinuxKPI mutexes and asserts will
+ * not be skipped during panic().
+ */
+#ifdef CONFIG_NO_MUTEX_SKIP
+#define MUTEX_SKIP(void) 0
+#else
+#define MUTEX_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active)
+#endif
+
+#define mutex_lock(_m) do { \
+ if (MUTEX_SKIP()) \
+ break; \
+ sx_xlock(&(_m)->sx); \
+} while (0)
+
#define mutex_lock_nested(_m, _s) mutex_lock(_m)
-#define mutex_lock_interruptible(_m) ({ mutex_lock((_m)); 0; })
-#define mutex_unlock(_m) sx_xunlock(&(_m)->sx)
-#define mutex_trylock(_m) !!sx_try_xlock(&(_m)->sx)
+#define mutex_lock_nest_lock(_m, _s) mutex_lock(_m)
+
+#define mutex_lock_interruptible(_m) ({ \
+ MUTEX_SKIP() ? 0 : \
+ (sx_xlock_sig(&(_m)->sx) ? -EINTR : 0); \
+})
+
+#define mutex_unlock(_m) do { \
+ if (MUTEX_SKIP()) \
+ break; \
+ sx_xunlock(&(_m)->sx); \
+} while (0)
+
+#define mutex_trylock(_m) ({ \
+ MUTEX_SKIP() ? 1 : \
+ !!sx_try_xlock(&(_m)->sx); \
+})
+
+#define mutex_init(_m) \
+ linux_mutex_init(_m, mutex_name(#_m), SX_NOWITNESS)
+
+#define mutex_init_witness(_m) \
+ linux_mutex_init(_m, mutex_name(#_m), SX_DUPOK)
+
+#define mutex_destroy(_m) \
+ linux_mutex_destroy(_m)
+
+static inline bool
+mutex_is_locked(mutex_t *m)
+{
+ return ((struct thread *)SX_OWNER(m->sx.sx_lock) != NULL);
+}
-#define DEFINE_MUTEX(lock) \
+static inline bool
+mutex_is_owned(mutex_t *m)
+{
+ return (sx_xlocked(&m->sx));
+}
+
+#ifdef WITNESS_ALL
+/* NOTE: the maximum WITNESS name is 64 chars */
+#define __mutex_name(name, file, line) \
+ (((const char *){file ":" #line "-" name}) + \
+ (sizeof(file) > 16 ? sizeof(file) - 16 : 0))
+#else
+#define __mutex_name(name, file, line) name
+#endif
+#define _mutex_name(...) __mutex_name(__VA_ARGS__)
+#define mutex_name(name) _mutex_name(name, __FILE__, __LINE__)
+
+#define DEFINE_MUTEX(lock) \
mutex_t lock; \
- SX_SYSINIT_FLAGS(lock, &(lock).sx, "lnxmtx", SX_NOWITNESS)
+ SX_SYSINIT_FLAGS(lock, &(lock).sx, mutex_name(#lock), SX_DUPOK)
static inline void
-linux_mutex_init(mutex_t *m)
+linux_mutex_init(mutex_t *m, const char *name, int flags)
{
-
- memset(&m->sx, 0, sizeof(m->sx));
- sx_init_flags(&m->sx, "lnxmtx", SX_NOWITNESS);
+ memset(m, 0, sizeof(*m));
+ sx_init_flags(&m->sx, name, flags);
}
-#define mutex_init(m) linux_mutex_init(m)
+static inline void
+linux_mutex_destroy(mutex_t *m)
+{
+ if (mutex_is_owned(m))
+ mutex_unlock(m);
+ sx_destroy(&m->sx);
+}
-#endif /* _LINUX_MUTEX_H_ */
+#endif /* _LINUX_MUTEX_H_ */
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