net: add sparse annotation to ptype_seq_start/stop

Get rid of some more sparse warnings.

Signed-off-by Stephen Hemminger <[email protected]>

net/core/dev.c +2 -1

@@ -2543,6 +2543,7 @@ static void *ptype_get_idx(loff_t pos)
 }
 
 static void *ptype_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(rcu)
 {
 	rcu_read_lock();
 	return *pos ? ptype_get_idx(*pos - 1) : SEQ_START_TOKEN;

@@ -2578,6 +2579,7 @@ found:
 }
 
 static void ptype_seq_stop(struct seq_file *seq, void *v)
+	__releases(rcu)
 {
 	rcu_read_unlock();
 }
--

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Quoted 3 lines · Stephen Hemminger

Get rid of some more sparse warnings.

Signed-off-by Stephen Hemminger <[email protected]>

Adding Josh to CC -- is __acquires() case-insensitive? If not, this needs to be __acquires(RCU) and __releases(RCU).

Quoted 7 lines · Paul E. McKenney

Quoted 3 lines · Stephen Hemminger

Get rid of some more sparse warnings.

Signed-off-by Stephen Hemminger <[email protected]>

Adding Josh to CC -- is __acquires() case-insensitive? If not, this needs to be __acquires(RCU) and __releases(RCU).

__acquires(whatever_the_helk_you_put_as_its_argument) is all the same.

Quoted 3 lines · Stephen Hemminger

Get rid of some more sparse warnings.

Signed-off-by Stephen Hemminger <[email protected]>

Adding Josh to CC -- is __acquires() case-insensitive? If not, this needs to be __acquires(RCU) and __releases(RCU).

Quoted 13 lines

net/core/dev.c +1 -0

@@ -2543,6 +2543,7 @@ static void *ptype_get_idx(loff_t pos)
 }
 
 static void *ptype_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(rcu)
 {
 	rcu_read_lock();
 	return *pos ? ptype_get_idx(*pos - 1) : SEQ_START_TOKEN;

@@ -2578,6 +2579,7 @@ found:
 }
 

net/core/dev.c found: · line 2585

Quoted 5 lines

net/core/dev.c +1 -0

 static void ptype_seq_stop(struct seq_file *seq, void *v)
+	__releases(rcu)
 {
 	rcu_read_unlock();
 }

At the moment, Sparse doesn't actually use the context expression. In the ideal case when it does, all references to the same lock should use a context expression which resolves to that lock (whatever that may mean; hence why Sparse doesn't handle it yet). For mechanisms like RCU without a lock variable, this will likely entail some sort of fake lock expression, which again needs to match between all users of the same mechanism. Like any expression in C, case matters; thus, please match the existing references to "RCU" rather than "rcu".