git: 33ba6077b0f1 - main - linuxkpi: Alias `sd` field of `struct kobject`

The branch main has been updated by dumbbell:

URL: https://cgit.FreeBSD.org/src/commit/?id=33ba6077b0f162091bf0871686304916458420d3

commit 33ba6077b0f162091bf0871686304916458420d3
Author:     Jean-Sébastien Pédron <dumbbell@FreeBSD.org>
AuthorDate: 2026-06-12 20:44:43 +0000
Commit:     Jean-Sébastien Pédron <dumbbell@FreeBSD.org>
CommitDate: 2026-09-07 18:27:29 +0000

    linuxkpi: Alias `sd` field of `struct kobject`
    
    On Linux, a `struct kernfs_node *` pointer, representing a directory in
    sysfs, is kept in the `sd` struct field.
    
    We don't have that on FreeBSD because we use sysctls instead. Let's
    alias the sysctl OID pointer to `sd` using an union.
    
    This pointer is checked by the DRM drivers using:
        if (var->kobj.sd) {
            ...
        }
    
    The amdgpu DRM driver started to use these checks in Linux 6.13.
    
    Reviewed by:    bz
    Sponsored by:   The FreeBSD Foundation
    Differential Revision: https://reviews.freebsd.org/D57586
---
 sys/compat/linuxkpi/common/include/linux/kobject.h | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/sys/compat/linuxkpi/common/include/linux/kobject.h b/sys/compat/linuxkpi/common/include/linux/kobject.h
index 3d053212f94e..cce604bdfb4e 100644
--- a/sys/compat/linuxkpi/common/include/linux/kobject.h
+++ b/sys/compat/linuxkpi/common/include/linux/kobject.h
@@ -60,7 +60,22 @@ struct kobject {
 	struct kref		kref;
 	const struct kobj_type	*ktype;
 	struct list_head	entry;
-	struct sysctl_oid	*oidp;
+	union {
+		struct sysctl_oid	*oidp;
+
+		/*
+		 * On Linux, a `struct kernfs_node *` pointer, representing a
+		 * directory in sysfs, is kept in the `sd` struct field.
+		 *
+		 * We don't have that on FreeBSD because we use sysctls
+		 * instead. Let's alias the sysctl OID pointer to `sd`. This
+		 * pointer is checked by the DRM drivers using:
+		 *     if (var->kobj.sd) {
+		 *         ...
+		 *     }
+		 */
+		void			*sd;
+	};
 	struct kset		*kset;
 };