[RFC PATCH 1/1] smp: Change function signatures to use call_single_data_t
From: Leonardo Bras
Date: Thu Aug 31 2023 - 02:50:24 EST
call_single_data_t is a size-aligned typedef of struct __call_single_data.
This alignment is desirable in order to have smp_call_function*() avoid
bouncing an extra cacheline in case of an unaligned csd, given this
would hurt performance.
Since the removal of struct request->csd in commit 660e802c76c8
("blk-mq: use percpu csd to remote complete instead of per-rq csd") there
are no current users of smp_call_function*() with unaligned csd.
Change every 'struct __call_single_data' function parameter to
'call_single_data_t', so we have warnings if any new code tries to
introduce an smp_call_function*() call with unaligned csd.
Signed-off-by: Leonardo Bras <leobras@xxxxxxxxxx>
---
include/linux/smp.h | 2 +-
include/trace/events/csd.h | 8 ++++----
kernel/smp.c | 26 +++++++++++++-------------
kernel/up.c | 2 +-
4 files changed, 19 insertions(+), 19 deletions(-)
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 91ea4a67f8ca..e87520dc2959 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -53,7 +53,7 @@ int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait, const struct cpumask *mask);
-int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
+int smp_call_function_single_async(int cpu, call_single_data_t *csd);
/*
* Cpus stopping functions in panic. All have default weak definitions.
diff --git a/include/trace/events/csd.h b/include/trace/events/csd.h
index 67e9d01f80c2..58cc83b99c34 100644
--- a/include/trace/events/csd.h
+++ b/include/trace/events/csd.h
@@ -12,7 +12,7 @@ TRACE_EVENT(csd_queue_cpu,
TP_PROTO(const unsigned int cpu,
unsigned long callsite,
smp_call_func_t func,
- struct __call_single_data *csd),
+ call_single_data_t *csd),
TP_ARGS(cpu, callsite, func, csd),
@@ -39,7 +39,7 @@ TRACE_EVENT(csd_queue_cpu,
*/
DECLARE_EVENT_CLASS(csd_function,
- TP_PROTO(smp_call_func_t func, struct __call_single_data *csd),
+ TP_PROTO(smp_call_func_t func, call_single_data_t *csd),
TP_ARGS(func, csd),
@@ -57,12 +57,12 @@ DECLARE_EVENT_CLASS(csd_function,
);
DEFINE_EVENT(csd_function, csd_function_entry,
- TP_PROTO(smp_call_func_t func, struct __call_single_data *csd),
+ TP_PROTO(smp_call_func_t func, call_single_data_t *csd),
TP_ARGS(func, csd)
);
DEFINE_EVENT(csd_function, csd_function_exit,
- TP_PROTO(smp_call_func_t func, struct __call_single_data *csd),
+ TP_PROTO(smp_call_func_t func, call_single_data_t *csd),
TP_ARGS(func, csd)
);
diff --git a/kernel/smp.c b/kernel/smp.c
index 8455a53465af..8c714583786b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -127,7 +127,7 @@ send_call_function_ipi_mask(struct cpumask *mask)
}
static __always_inline void
-csd_do_func(smp_call_func_t func, void *info, struct __call_single_data *csd)
+csd_do_func(smp_call_func_t func, void *info, call_single_data_t *csd)
{
trace_csd_function_entry(func, csd);
func(info);
@@ -174,7 +174,7 @@ module_param(csd_lock_timeout, ulong, 0444);
static atomic_t csd_bug_count = ATOMIC_INIT(0);
/* Record current CSD work for current CPU, NULL to erase. */
-static void __csd_lock_record(struct __call_single_data *csd)
+static void __csd_lock_record(call_single_data_t *csd)
{
if (!csd) {
smp_mb(); /* NULL cur_csd after unlock. */
@@ -189,13 +189,13 @@ static void __csd_lock_record(struct __call_single_data *csd)
/* Or before unlock, as the case may be. */
}
-static __always_inline void csd_lock_record(struct __call_single_data *csd)
+static __always_inline void csd_lock_record(call_single_data_t *csd)
{
if (static_branch_unlikely(&csdlock_debug_enabled))
__csd_lock_record(csd);
}
-static int csd_lock_wait_getcpu(struct __call_single_data *csd)
+static int csd_lock_wait_getcpu(call_single_data_t *csd)
{
unsigned int csd_type;
@@ -210,7 +210,7 @@ static int csd_lock_wait_getcpu(struct __call_single_data *csd)
* the CSD_TYPE_SYNC/ASYNC types provide the destination CPU,
* so waiting on other types gets much less information.
*/
-static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *ts1, int *bug_id)
+static bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, int *bug_id)
{
int cpu = -1;
int cpux;
@@ -276,7 +276,7 @@ static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *
* previous function call. For multi-cpu calls its even more interesting
* as we'll have to ensure no other cpu is observing our csd.
*/
-static void __csd_lock_wait(struct __call_single_data *csd)
+static void __csd_lock_wait(call_single_data_t *csd)
{
int bug_id = 0;
u64 ts0, ts1;
@@ -290,7 +290,7 @@ static void __csd_lock_wait(struct __call_single_data *csd)
smp_acquire__after_ctrl_dep();
}
-static __always_inline void csd_lock_wait(struct __call_single_data *csd)
+static __always_inline void csd_lock_wait(call_single_data_t *csd)
{
if (static_branch_unlikely(&csdlock_debug_enabled)) {
__csd_lock_wait(csd);
@@ -300,17 +300,17 @@ static __always_inline void csd_lock_wait(struct __call_single_data *csd)
smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK));
}
#else
-static void csd_lock_record(struct __call_single_data *csd)
+static void csd_lock_record(call_single_data_t *csd)
{
}
-static __always_inline void csd_lock_wait(struct __call_single_data *csd)
+static __always_inline void csd_lock_wait(call_single_data_t *csd)
{
smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK));
}
#endif
-static __always_inline void csd_lock(struct __call_single_data *csd)
+static __always_inline void csd_lock(call_single_data_t *csd)
{
csd_lock_wait(csd);
csd->node.u_flags |= CSD_FLAG_LOCK;
@@ -323,7 +323,7 @@ static __always_inline void csd_lock(struct __call_single_data *csd)
smp_wmb();
}
-static __always_inline void csd_unlock(struct __call_single_data *csd)
+static __always_inline void csd_unlock(call_single_data_t *csd)
{
WARN_ON(!(csd->node.u_flags & CSD_FLAG_LOCK));
@@ -376,7 +376,7 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
* for execution on the given CPU. data must already have
* ->func, ->info, and ->flags set.
*/
-static int generic_exec_single(int cpu, struct __call_single_data *csd)
+static int generic_exec_single(int cpu, call_single_data_t *csd)
{
if (cpu == smp_processor_id()) {
smp_call_func_t func = csd->func;
@@ -667,7 +667,7 @@ EXPORT_SYMBOL(smp_call_function_single);
*
* Return: %0 on success or negative errno value on error
*/
-int smp_call_function_single_async(int cpu, struct __call_single_data *csd)
+int smp_call_function_single_async(int cpu, call_single_data_t *csd)
{
int err = 0;
diff --git a/kernel/up.c b/kernel/up.c
index a38b8b095251..df50828cc2f0 100644
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -25,7 +25,7 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
}
EXPORT_SYMBOL(smp_call_function_single);
-int smp_call_function_single_async(int cpu, struct __call_single_data *csd)
+int smp_call_function_single_async(int cpu, call_single_data_t *csd)
{
unsigned long flags;
--
2.42.0