PR/60980 CVS commit: src/sys/external/bsd/common/include/linux

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

The following reply was made to PR kern/60980; it has been noted by GNATS.

From: "Taylor R Campbell" <riastradh%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/60980 CVS commit: src/sys/external/bsd/common/include/linux
Date: Sat, 7 Nov 2026 10:08:16 +0000

 Module Name:	src
 Committed By:	riastradh
 Date:		Sat Nov  7 10:08:16 UTC 2026
 
 Modified Files:
 	src/sys/external/bsd/common/include/linux: rcupdate.h
 
 Log Message:
 drm: Fix rcu_replace_pointer.
 
 This Linux API macro takes an _lvalue_ expression for an object, not
 a pointer to the object -- unlike, e.g., the atomic_load/store
 functions.  So we can't copy its value into a local variable (to
 avoid duplicate macro argument expansion) and then assign the local
 variable with rcu_assign_pointer because that will only modify the
 local copy, not the caller's lvalue!
 
 Rename the macro parameters to make this clearer so it doesn't trip
 me up again next time I read this.
 
 Probably fixes dozens of graphics problems on a generation of Intel
 hardware.  Derp!
 
 PR kern/60980: rcu_replace_pointer() fails to update the original pointer
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.8 -r1.9 src/sys/external/bsd/common/include/linux/rcupdate.h
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.