git: 52d2fc702b85 - main - linuxkpi: Fix an off-by-one error in the kfifo implementation

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=52d2fc702b85d56b35f8828fe7efca3cde0d25b7

commit 52d2fc702b85d56b35f8828fe7efca3cde0d25b7
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2026-04-15 13:33:04 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-04-15 13:33:04 +0000

    linuxkpi: Fix an off-by-one error in the kfifo implementation
    
    "total" is the number of slots in the array, so wraparound needs to be
    done when "first" or "last" is greater than or equal to the number of
    slots.
    
    Note that no consumers of the code are currently connected to the kernel
    build.
    
    Reported by:    Stanislav Fort <stanislav.fort@aisle.com>
    Reviewed by:    bz, emaste
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D56371
---
 sys/compat/linuxkpi/common/include/linux/kfifo.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sys/compat/linuxkpi/common/include/linux/kfifo.h b/sys/compat/linuxkpi/common/include/linux/kfifo.h
index fbe16e22683e..b0d0c17f07e4 100644
--- a/sys/compat/linuxkpi/common/include/linux/kfifo.h
+++ b/sys/compat/linuxkpi/common/include/linux/kfifo.h
@@ -89,7 +89,7 @@
 		(_kf)->head[(_kf)->last] = (_e);			\
 		(_kf)->count++;						\
 		(_kf)->last++;						\
-		if ((_kf)->last > (_kf)->total)				\
+		if ((_kf)->last >= (_kf)->total)			\
 			(_kf)->last = 0;				\
 		_rc = true;						\
 	}								\
@@ -107,7 +107,7 @@
 		*(_e) = (_kf)->head[(_kf)->first];			\
 		(_kf)->count--;						\
 		(_kf)->first++;						\
-		if ((_kf)->first > (_kf)->total)			\
+		if ((_kf)->first >= (_kf)->total)			\
 			(_kf)->first = 0;				\
 		_rc = true;						\
 	}								\