The patch titled
Subject: lib/dynamic_debug.c: drop use of bitfields in struct _ddebug
has been added to the -mm tree. Its filename is
dynamic_debug-drop-use-of-bitfields-in-struct-_ddebug.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/dynamic_debug-drop-use-of-bitfields-in-struct-_ddebug.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/dynamic_debug-drop-use-of-bitfields-in-struct-_ddebug.patch
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------------------------------------------------------
From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Subject: lib/dynamic_debug.c: drop use of bitfields in struct _ddebug
Properly initializing a struct containing bitfields in assembly is hard.
Instead, merge lineno and flags to a single unsigned int, which we mask
manually. This should not cause any worse code than what gcc would need
to generate for accessing the bitfields anyway.
Actually, on 64 bit, there is a four byte hole after these fields, so we
could just give flags and lineno each their own u32. But I don't think
that's worth the ifdeffery.
Link: http://lkml.kernel.org/r/20190409212517.7321-6-linux@xxxxxxxxxxxxxxxxxx
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Acked-by: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/dynamic_debug.h | 12 +++-----
lib/dynamic_debug.c | 44 +++++++++++++++++++++-----------
2 files changed, 34 insertions(+), 22 deletions(-)
--- a/include/linux/dynamic_debug.h~dynamic_debug-drop-use-of-bitfields-in-struct-_ddebug
+++ a/include/linux/dynamic_debug.h
@@ -20,7 +20,6 @@ struct _ddebug {
const char *function;
const char *filename;
const char *format;
- unsigned int lineno:18;
/*
* The flags field controls the behaviour at the callsite.
* The bits here are changed dynamically when the user
@@ -37,7 +36,7 @@ struct _ddebug {
#else
#define _DPRINTK_FLAGS_DEFAULT 0
#endif
- unsigned int flags:8;
+ unsigned int flags_lineno; /* flags in lower 8 bits, lineno in upper 24 */
#ifdef CONFIG_JUMP_LABEL
union {
struct static_key_true dd_key_true;
@@ -46,7 +45,7 @@ struct _ddebug {
#endif
} __attribute__((aligned(8)));
-
+#define _DPRINTK_FLAGS_LINENO_INIT (((unsigned)__LINE__ << 8) | _DPRINTK_FLAGS_DEFAULT)
#if defined(CONFIG_DYNAMIC_DEBUG)
int ddebug_add_module(struct _ddebug *tab, unsigned int n,
@@ -78,8 +77,7 @@ void __dynamic_netdev_dbg(struct _ddebug
.function = __func__, \
.filename = __FILE__, \
.format = (fmt), \
- .lineno = __LINE__, \
- .flags = _DPRINTK_FLAGS_DEFAULT, \
+ .flags_lineno = _DPRINTK_FLAGS_LINENO_INIT, \
_DPRINTK_KEY_INIT \
}
@@ -104,10 +102,10 @@ void __dynamic_netdev_dbg(struct _ddebug
#ifdef DEBUG
#define DYNAMIC_DEBUG_BRANCH(descriptor) \
- likely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
+ likely(descriptor.flags_lineno & _DPRINTK_FLAGS_PRINT)
#else
#define DYNAMIC_DEBUG_BRANCH(descriptor) \
- unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
+ unlikely(descriptor.flags_lineno & _DPRINTK_FLAGS_PRINT)
#endif
#endif
--- a/lib/dynamic_debug.c~dynamic_debug-drop-use-of-bitfields-in-struct-_ddebug
+++ a/lib/dynamic_debug.c
@@ -53,6 +53,18 @@ static inline const char *dd_format(cons
{
return dd->format;
}
+static inline unsigned dd_lineno(const struct _ddebug *dd)
+{
+ return dd->flags_lineno >> 8;
+}
+static inline unsigned dd_flags(const struct _ddebug *dd)
+{
+ return dd->flags_lineno & 0xff;
+}
+static inline void dd_set_flags(struct _ddebug *dd, unsigned newflags)
+{
+ dd->flags_lineno = (dd_lineno(dd) << 8) | newflags;
+}
extern struct _ddebug __start___verbose[];
extern struct _ddebug __stop___verbose[];
@@ -111,7 +123,7 @@ static char *ddebug_describe_flags(struc
BUG_ON(maxlen < 6);
for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
- if (dp->flags & opt_array[i].flag)
+ if (dd_flags(dp) & opt_array[i].flag)
*p++ = opt_array[i].opt_char;
if (p == buf)
*p++ = '_';
@@ -157,7 +169,7 @@ static int ddebug_change(const struct dd
{
int i;
struct ddebug_table *dt;
- unsigned int newflags;
+ unsigned int newflags, oldflags;
unsigned int nfound = 0;
char flagbuf[10];
@@ -194,27 +206,28 @@ static int ddebug_change(const struct dd
/* match against the line number range */
if (query->first_lineno &&
- dp->lineno < query->first_lineno)
+ dd_lineno(dp) < query->first_lineno)
continue;
if (query->last_lineno &&
- dp->lineno > query->last_lineno)
+ dd_lineno(dp) > query->last_lineno)
continue;
nfound++;
- newflags = (dp->flags & mask) | flags;
- if (newflags == dp->flags)
+ oldflags = dd_flags(dp);
+ newflags = (oldflags & mask) | flags;
+ if (newflags == oldflags)
continue;
#ifdef CONFIG_JUMP_LABEL
- if (dp->flags & _DPRINTK_FLAGS_PRINT) {
+ if (oldflags & _DPRINTK_FLAGS_PRINT) {
if (!(flags & _DPRINTK_FLAGS_PRINT))
static_branch_disable(&dp->key.dd_key_true);
} else if (flags & _DPRINTK_FLAGS_PRINT)
static_branch_enable(&dp->key.dd_key_true);
#endif
- dp->flags = newflags;
+ dd_set_flags(dp, newflags);
vpr_info("changed %s:%d [%s]%s =%s\n",
- trim_prefix(dd_filename(dp)), dp->lineno,
+ trim_prefix(dd_filename(dp)), dd_lineno(dp),
dt->mod_name, dd_function(dp),
ddebug_describe_flags(dp, flagbuf,
sizeof(flagbuf)));
@@ -537,10 +550,11 @@ static char *dynamic_emit_prefix(const s
{
int pos_after_tid;
int pos = 0;
+ unsigned flags = dd_flags(desc);
*buf = '\0';
- if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
+ if (flags & _DPRINTK_FLAGS_INCL_TID) {
if (in_interrupt())
pos += snprintf(buf + pos, remaining(pos), "<intr> ");
else
@@ -548,15 +562,15 @@ static char *dynamic_emit_prefix(const s
task_pid_vnr(current));
}
pos_after_tid = pos;
- if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
+ if (flags & _DPRINTK_FLAGS_INCL_MODNAME)
pos += snprintf(buf + pos, remaining(pos), "%s:",
dd_modname(desc));
- if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
+ if (flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
pos += snprintf(buf + pos, remaining(pos), "%s:",
dd_function(desc));
- if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
+ if (flags & _DPRINTK_FLAGS_INCL_LINENO)
pos += snprintf(buf + pos, remaining(pos), "%d:",
- desc->lineno);
+ dd_lineno(desc));
if (pos - pos_after_tid)
pos += snprintf(buf + pos, remaining(pos), " ");
if (pos >= PREFIX_SIZE)
@@ -807,7 +821,7 @@ static int ddebug_proc_show(struct seq_f
}
seq_printf(m, "%s:%u [%s]%s =%s \"",
- trim_prefix(dd_filename(dp)), dp->lineno,
+ trim_prefix(dd_filename(dp)), dd_lineno(dp),
iter->table->mod_name, dd_function(dp),
ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
seq_escape(m, dd_format(dp), "\t\r\n\"");
_
Patches currently in -mm which might be from linux@xxxxxxxxxxxxxxxxxx are
linux-deviceh-use-unique-identifier-for-each-struct-_ddebug.patch
linux-neth-use-unique-identifier-for-each-struct-_ddebug.patch
linux-printkh-use-unique-identifier-for-each-struct-_ddebug.patch
dynamic_debug-introduce-accessors-for-string-members-of-struct-_ddebug.patch
dynamic_debug-drop-use-of-bitfields-in-struct-_ddebug.patch
dynamic_debug-introduce-config_dynamic_debug_relative_pointers.patch
dynamic_debug-add-asm-generic-implementation-for-dynamic_debug_relative_pointers.patch
x86-64-select-dynamic_debug_relative_pointers.patch
arm64-select-dynamic_debug_relative_pointers.patch
powerpc-select-dynamic_debug_relative_pointers-for-ppc64.patch
lib-bitmapc-remove-unused-export_symbols.patch
lib-bitmapc-guard-exotic-bitmap-functions-by-config_numa.patch
bitopsh-sanitize-rotate-primitives.patch
