MFC r303151:

Provide counter_warning(9) KPI.

MFC r303155:
Hide counted_warning(9) under #ifdef _KERNEL braces.

Approved by:	re (gjb)

3 files changed, 27 insertions, 9 deletions

diff --git a/sys/dev/pty/pty.c b/sys/dev/pty/pty.c
index 5036cb2..ad34e11 100644
--- a/sys/dev/pty/pty.c
+++ b/sys/dev/pty/pty.c
@@ -52,10 +52,10 @@ __FBSDID("$FreeBSD$");
  * binary emulation.
  */
 
-static unsigned int pty_warningcnt = 1;
+static unsigned pty_warningcnt = 1;
 SYSCTL_UINT(_kern, OID_AUTO, tty_pty_warningcnt, CTLFLAG_RW,
-	&pty_warningcnt, 0,
-	"Warnings that will be triggered upon legacy PTY allocation");
+    &pty_warningcnt, 0,
+    "Warnings that will be triggered upon legacy PTY allocation");
 
 static int
 ptydev_fdopen(struct cdev *dev, int fflags, struct thread *td, struct file *fp)
@@ -77,12 +77,7 @@ ptydev_fdopen(struct cdev *dev, int fflags, struct thread *td, struct file *fp)
 	}
 
 	/* Raise a warning when a legacy PTY has been allocated. */
-	if (pty_warningcnt > 0) {
-		pty_warningcnt--;
-		log(LOG_INFO, "pid %d (%s) is using legacy pty devices%s\n",
-		    td->td_proc->p_pid, td->td_name,
-		    pty_warningcnt ? "" : " - not logging anymore");
-	}
+	counted_warning(&pty_warningcnt, "is using legacy pty devices");
 
 	return (0);
 }
diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c
index 5bcf39b..3784ffd 100644
--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -1196,3 +1196,24 @@ sbuf_hexdump(struct sbuf *sb, const void *ptr, int length, const char *hdr,
 	}
 }
 
+#ifdef _KERNEL
+void
+counted_warning(unsigned *counter, const char *msg)
+{
+	struct thread *td;
+	unsigned c;
+
+	for (;;) {
+		c = *counter;
+		if (c == 0)
+			break;
+		if (atomic_cmpset_int(counter, c, c - 1)) {
+			td = curthread;
+			log(LOG_INFO, "pid %d (%s) %s%s\n",
+			    td->td_proc->p_pid, td->td_name, msg,
+			    c > 1 ? "" : " - not logging anymore");
+			break;
+		}
+	}
+}
+#endif
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index dae6adc..f47ba2d 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -447,4 +447,6 @@ void	intr_prof_stack_use(struct thread *td, struct trapframe *frame);
 
 extern void (*softdep_ast_cleanup)(void);
 
+void counted_warning(unsigned *counter, const char *msg);
+
 #endif /* !_SYS_SYSTM_H_ */