lib: sbi: dbtr: fix potential NULL pointer dereferences

In several dbtr functions, we first check that the dbtr trigger is not
NULL and that its state is what we expect. However, it only makes
sense to perform the second check if the dbtr trigger is not NULL.
Othwerwise we will dereference a NULL pointer. Thus, change the
condition so that it shortcuts to the first check if necessary.

Signed-off-by: Carlos López <[email protected]>
Reviewed-By: Anup Patel <[email protected]>

Author: 00xc

lib/sbi/sbi_dbtr.c

@@ -357,7 +357,7 @@ static void dbtr_trigger_enable(struct sbi_dbtr_trigger *trig)
 	unsigned long state;
 	unsigned long tdata1;
 
-	if (!trig && !(trig->state & RV_DBTR_BIT_MASK(TS, MAPPED)))
+	if (!trig || !(trig->state & RV_DBTR_BIT_MASK(TS, MAPPED)))
 		return;
 
 	state = trig->state;
@@ -403,7 +403,7 @@ static void dbtr_trigger_disable(struct sbi_dbtr_trigger *trig)
 {
 	unsigned long tdata1;
 
-	if (!trig && !(trig->state & RV_DBTR_BIT_MASK(TS, MAPPED)))
+	if (!trig || !(trig->state & RV_DBTR_BIT_MASK(TS, MAPPED)))
 		return;
 
 	tdata1 = trig->tdata1;
@@ -429,7 +429,7 @@ static void dbtr_trigger_disable(struct sbi_dbtr_trigger *trig)
 
 static void dbtr_trigger_clear(struct sbi_dbtr_trigger *trig)
 {
-	if (!trig && !(trig->state & RV_DBTR_BIT_MASK(TS, MAPPED)))
+	if (!trig || !(trig->state & RV_DBTR_BIT_MASK(TS, MAPPED)))
 		return;
 
 	csr_write(CSR_TSELECT, trig->index);