git: 42061b62cc58 - stable/12 - Fix false device_set_unit() error.

[Alexander Motin]

The branch stable/12 has been updated by mav:

URL: https://cgit.FreeBSD.org/src/commit/?id=42061b62cc58b42396d394c69bf958f9e05dc959

commit 42061b62cc58b42396d394c69bf958f9e05dc959
Author:     Alexander Motin <mav at FreeBSD.org>
AuthorDate: 2021-09-22 12:42:36 +0000
Commit:     Alexander Motin <mav at FreeBSD.org>
CommitDate: 2021-09-29 00:44:40 +0000

    Fix false device_set_unit() error.
    
    It should silently succeed if the current unit number is the same as
    requested, not fail immediately.
    
    MFC after:      1 week
    
    (cherry picked from commit 884f38590c3cc0b1a2c00904c1f1f6c791376308)
---
 sys/kern/subr_bus.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index 46c098237f48..92c9eb4dd6d5 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -3089,6 +3089,8 @@ device_set_unit(device_t dev, int unit)
 	devclass_t dc;
 	int err;
 
+	if (unit == dev->unit)
+		return (0);
 	dc = device_get_devclass(dev);
 	if (unit < dc->maxunit && dc->devices[unit])
 		return (EBUSY);