Change the definition of dprintk() to generate an array of records in
a special new .dprintk section, which describe the module, filename,
line number, function, and printk format of each dprintk.
Signed-off-by: Greg Banks <gnb@xxxxxxx>
---
include/linux/dprintk.h | 91 ++++++++++++++++++++++++++++++
include/linux/lockd/debug.h | 6 -
include/linux/nfs_fs.h | 18 -----
include/linux/nfsd/debug.h | 12 +--
include/linux/sunrpc/debug.h | 29 +++++++--
net/sunrpc/cache.c | 2
net/sunrpc/xprtrdma/rpc_rdma.c | 2
7 files changed, 124 insertions(+), 36 deletions(-)
Index: bfields/include/linux/dprintk.h
===================================================================
--- /dev/null
+++ bfields/include/linux/dprintk.h
@@ -0,0 +1,91 @@
+/*
+ * dprintk.h - a generic /proc interface for enabling individual debugging printks.
+ *
+ * By Greg Banks <gnb@xxxxxxxxxxxxxxxxx>
+ * Copyright (c) 2008 Silicon Graphics Inc. All Rights Reserved.
+ * $Id: dprintk.h,v 1.1 2008/09/04 04:46:06 gnb Exp $
+ */
+#ifndef _LINUX_DPRINTK_H_
+#define _LINUX_DPRINTK_H_ 1
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+/*
+ * An instance of this structure is created in a special
+ * ELF section at every dprintk() callsite. At runtime,
+ * the special section is treated as an array of these.
+ */
+struct _dprintk
+{
+ /*
+ * These fields are used to drive the /proc user interface
+ * for selecting and displaying dprintk() callsites.
+ */
+ const char *function;
+ const char *filename;
+ const char *format;
+ unsigned int lineno;
+ /*
+ * This magic number helps finding the bound of the special
+ * ELF section (for various stupid reasons we don't have an
+ * accurate idea of the end of the loaded section).
+ */
+#define _DPRINTK_MAGIC 0xc0ffee
+ unsigned int magic:24;
+ /*
+ * The flags field controls the behaviour at the callsite.
+ * The bits here are changed dynamically when the user
+ * writes commands to /proc/dprintk.
+ */
+#define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
+#define _DPRINTK_FLAGS_STACK (1<<1) /* print a kernel stack using dump_stack() */
+#define _DPRINTK_FLAGS_CRASH (1<<2) /* cause a kernel crash for debugging */
+#define _DPRINTK_FLAGS_DEFAULT 0
+ unsigned int flags:8;
+};
+
+
+/*
+ * Basic callsite functionality. The `cond' argument allows
+ * the caller to add an extra logical condition to the check
+ * for printk(). The NFS code uses that to implement a
+ * dfprintk() macro which is dprintk() with an additional
+ * check of the NFS global debug bitmasks.
+ */
+#define __dprintk(cond, fmt, ...) \
+do { \
+ static struct _dprintk \
+ __attribute__((section(".dprintk"))) _dp = { \
+ .function = __FUNCTION__, \
+ .filename = __FILE__, \
+ .format = fmt, \
+ .lineno = __LINE__, \
+ .magic = _DPRINTK_MAGIC, \
+ .flags = _DPRINTK_FLAGS_DEFAULT \
+ }; \
+ if (unlikely(_dp.flags || (cond))) \
+ printk(_dp.format, ## __VA_ARGS__); \
+ if (unlikely(_dp.flags & _DPRINTK_FLAGS_STACK)) \
+ dump_stack(); \
+ BUG_ON(_dp.flags & _DPRINTK_FLAGS_CRASH); \
+} while(0)
+
+/*
+ * Default definition of dprintk_check. This macro exists
+ * only to allow calling code to redefine it to add extra
+ * logic which enables dprintk() callsites in ways other
+ * than the individual callsite flags. For example, NFS
+ * uses this to implement backwards-compatible global debug
+ * bitmasks.
+ */
+#ifndef dprintk_check
+#define dprintk_check 0
+#endif
+
+/*
+ * This is the macro that most calling code should be using.
+ */
+#define dprintk(fmt, ...) __dprintk(dprintk_check, fmt, ## __VA_ARGS__)
+
+#endif /* _LINUX_DPRINTK_H_ */
Index: bfields/include/linux/lockd/debug.h
===================================================================
--- bfields.orig/include/linux/lockd/debug.h
+++ bfields/include/linux/lockd/debug.h
@@ -21,11 +21,9 @@
# define LOCKD_DEBUG 1
#endif
-#undef ifdebug
#if defined(RPC_DEBUG) && defined(LOCKD_DEBUG)
-# define ifdebug(flag) if (unlikely(nlm_debug & NLMDBG_##flag))
-#else
-# define ifdebug(flag) if (0)
+# undef debugcheck
+# define debugcheck(fac) (nlm_debug & NLMDBG_##fac)
#endif
#endif /* __KERNEL__ */
Index: bfields/include/linux/nfsd/debug.h
===================================================================
--- bfields.orig/include/linux/nfsd/debug.h
+++ bfields/include/linux/nfsd/debug.h
@@ -36,13 +36,9 @@
#define NFSDDBG_NOCHANGE 0xFFFF
-#ifdef __KERNEL__
-# undef ifdebug
-# ifdef NFSD_DEBUG
-# define ifdebug(flag) if (nfsd_debug & NFSDDBG_##flag)
-# else
-# define ifdebug(flag) if (0)
-# endif
-#endif /* __KERNEL__ */
+#if defined(__KERNEL__) && defined(NFSD_DEBUG)
+# undef debugcheck
+# define debugcheck(fac) (nfsd_debug & NFSDDBG_##fac)
+#endif
#endif /* LINUX_NFSD_DEBUG_H */
Index: bfields/include/linux/nfs_fs.h
===================================================================
--- bfields.orig/include/linux/nfs_fs.h
+++ bfields/include/linux/nfs_fs.h
@@ -598,22 +598,10 @@ extern void * nfs_root_data(void);
#define NFSDBG_FSCACHE 0x0800
#define NFSDBG_ALL 0xFFFF
-#ifdef __KERNEL__
-
-/*
- * Enable debugging support for nfs client.
- * Requires RPC_DEBUG.
- */
-#ifdef RPC_DEBUG
+#if defined(__KERNEL__) && defined(RPC_DEBUG)
# define NFS_DEBUG
+# undef debugcheck
+# define debugcheck(fac) (nfs_debug & NFSDBG_##fac)
#endif
-# undef ifdebug
-# ifdef NFS_DEBUG
-# define ifdebug(fac) if (unlikely(nfs_debug & NFSDBG_##fac))
-# else
-# define ifdebug(fac) if (0)
-# endif
-#endif /* __KERNEL */
-
#endif
Index: bfields/include/linux/sunrpc/debug.h
===================================================================
--- bfields.orig/include/linux/sunrpc/debug.h
+++ bfields/include/linux/sunrpc/debug.h
@@ -30,6 +30,7 @@
#include <linux/timer.h>
#include <linux/workqueue.h>
+#include <linux/dprintk.h>
/*
* Enable RPC debugging/profiling.
@@ -41,6 +42,20 @@
/*
* Debugging macros etc
+ *
+ * The RPC (and NFS etc) code can do the following:
+ *
+ * a) at the start of a .c file set up the default
+ * debug bit to be used for all dprintk()s, e.g.
+ * #define RPCDBG_FACILITY RPCDBG_MISC
+ *
+ * b) call dprintk(), to do a debug print conditional
+ * on the default debug bit, e.g.
+ * dprintk("nfsd: write complete err=%d\n", err);
+ *
+ * c) call dfprintk(), to do a debug print conditional
+ * on a specified non-default debug bit, e.g.
+ * dfprintk(VFS, "NFS: find_dirent_index() returns %d\n", status);
*/
#ifdef RPC_DEBUG
extern unsigned int rpc_debug;
@@ -49,15 +64,15 @@ extern unsigned int nfsd_debug;
extern unsigned int nlm_debug;
#endif
-#define dprintk(args...) dfprintk(FACILITY, ## args)
-
-#undef ifdebug
-#ifdef RPC_DEBUG
-# define ifdebug(fac) if (unlikely(rpc_debug & RPCDBG_##fac))
-# define dfprintk(fac, args...) do { ifdebug(fac) printk(args); } while(0)
+#ifdef RPC_DEBUG
+# define debugcheck(fac) (rpc_debug & RPCDBG_##fac)
+# undef dprintk_check
+# define dprintk_check debugcheck(FACILITY)
+# define dfprintk(fac, args...) __dprintk(debugcheck(fac), args)
# define RPC_IFDEBUG(x) x
#else
-# define ifdebug(fac) if (0)
+# undef dprintk
+# define dprintk(args...) do ; while (0)
# define dfprintk(fac, args...) do ; while (0)
# define RPC_IFDEBUG(x)
#endif
Index: bfields/net/sunrpc/cache.c
===================================================================
--- bfields.orig/net/sunrpc/cache.c
+++ bfields/net/sunrpc/cache.c
@@ -1236,7 +1236,7 @@ static int c_show(struct seq_file *m, vo
if (p == SEQ_START_TOKEN)
return cd->cache_show(m, cd, NULL);
- ifdebug(CACHE)
+ if (unlikely(debugcheck(CACHE)))
seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
h->expiry_time, atomic_read(&h->ref.refcount), h->flags);
cache_get(h);
Index: bfields/net/sunrpc/xprtrdma/rpc_rdma.c
===================================================================
--- bfields.orig/net/sunrpc/xprtrdma/rpc_rdma.c
+++ bfields/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -568,7 +568,7 @@ rpcrdma_count_chunks(struct rpcrdma_rep
total_len = 0;
while (i--) {
struct rpcrdma_segment *seg = &cur_wchunk->wc_target;
- ifdebug(FACILITY) {
+ if (unlikely(debugcheck(FACILITY))) {
u64 off;
xdr_decode_hyper((__be32 *)&seg->rs_offset, &off);
dprintk("RPC: %s: chunk %d@0x%llx:0x%x\n",
--
--
Greg Banks, P.Engineer, SGI Australian Software Group.
the brightly coloured sporks of revolution.
I don't speak for SGI.
--
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