git: 168c7580c632 - main - file: add fo_cmp method

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=168c7580c6328342945db0e19a0791466bb07624

commit 168c7580c6328342945db0e19a0791466bb07624
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2024-01-19 21:01:35 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2024-01-24 05:11:26 +0000

    file: add fo_cmp method
    
    The method should return 0 if the file' underlying objects are same.  In
    other words, if 0 is returned, io from either of file causes
    modifications of the same object.
    
    Reviewed by:    brooks, markj
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D43518
---
 sys/sys/file.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sys/sys/file.h b/sys/sys/file.h
index 83da5105ad2b..80ed0e2db3bf 100644
--- a/sys/sys/file.h
+++ b/sys/sys/file.h
@@ -129,6 +129,7 @@ typedef int fo_fallocate_t(struct file *fp, off_t offset, off_t len,
 typedef int fo_fspacectl_t(struct file *fp, int cmd,
 		    off_t *offset, off_t *length, int flags,
 		    struct ucred *active_cred, struct thread *td);
+typedef int fo_cmp_t(struct file *fp, struct file *fp1, struct thread *td);
 typedef int fo_spare_t(struct file *fp);
 typedef	int fo_flags_t;
 
@@ -152,6 +153,7 @@ struct fileops {
 	fo_get_seals_t	*fo_get_seals;
 	fo_fallocate_t	*fo_fallocate;
 	fo_fspacectl_t	*fo_fspacectl;
+	fo_cmp_t	*fo_cmp;
 	fo_spare_t	*fo_spares[8];	/* Spare slots */
 	fo_flags_t	fo_flags;	/* DFLAG_* below */
 };
@@ -491,6 +493,15 @@ fo_fspacectl(struct file *fp, int cmd, off_t *offset, off_t *length,
 	    active_cred, td));
 }
 
+static __inline int
+fo_cmp(struct file *fp1, struct file *fp2, struct thread *td)
+{
+
+	if (fp1->f_ops->fo_cmp == NULL)
+		return (ENODEV);
+	return ((*fp1->f_ops->fo_cmp)(fp1, fp2, td));
+}
+
 #endif /* _KERNEL */
 
 #endif /* !SYS_FILE_H */