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i2c: Update i2c_trace_msg static key to modern api 

No changes in refcount semantics -- key init is false; replace

static_key_slow_inc|dec   with   static_branch_inc|dec
static_key_false          with   static_branch_unlikely

Added a '_key' suffix to i2c_trace_msg, for better self
documentation.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Davidlohr Bueso 2018-03-26 14:09:24 -07:00 committed by Wolfram Sang
parent 4a3f7691e2
commit 50888b015d
1 changed files with 7 additions and 6 deletions
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13
drivers/i2c/i2c-core-base.c
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@ -69,18 +69,18 @@ static DEFINE_IDR(i2c_adapter_idr);
static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
static bool is_registered;
int i2c_transfer_trace_reg(void)
{
static_key_slow_inc(&i2c_trace_msg);
static_branch_inc(&i2c_trace_msg_key);
return 0;
}
void i2c_transfer_trace_unreg(void)
{
static_key_slow_dec(&i2c_trace_msg);
static_branch_dec(&i2c_trace_msg_key);
}
const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
@ -1848,11 +1848,12 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
return -EOPNOTSUPP;
/* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
/*
* i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
* enabled. This is an efficient way of keeping the for-loop from
* being executed when not needed.
*/
if (static_key_false(&i2c_trace_msg)) {
if (static_branch_unlikely(&i2c_trace_msg_key)) {
int i;
for (i = 0; i < num; i++)
if (msgs[i].flags & I2C_M_RD)
@ -1871,7 +1872,7 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
break;
}
if (static_key_false(&i2c_trace_msg)) {
if (static_branch_unlikely(&i2c_trace_msg_key)) {
int i;
for (i = 0; i < ret; i++)
if (msgs[i].flags & I2C_M_RD)