git: 99efa2c88d93 - main - netmap: Ignore errors in CSB_WRITE()

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=99efa2c88d93c6272a8f54b18d18d0fd9d60f137

commit 99efa2c88d93c6272a8f54b18d18d0fd9d60f137
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2023-12-27 15:13:29 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2023-12-27 15:13:29 +0000

    netmap: Ignore errors in CSB_WRITE()
    
    The CSB_WRITE() and _READ() macros respectively write to and read from
    userspace memory and so can in principle fault.  However, we do not
    check for errors and will proceed blindly if they fail.  Add assertions
    to verify that they do not.
    
    This is in preparation for annotating copyin() and related functions
    with __result_use_check.
    
    Reviewed by:    vmaffione
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D43200
---
 sys/dev/netmap/netmap_kern.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/sys/dev/netmap/netmap_kern.h b/sys/dev/netmap/netmap_kern.h
index 24f741084a8d..8618aaf82299 100644
--- a/sys/dev/netmap/netmap_kern.h
+++ b/sys/dev/netmap/netmap_kern.h
@@ -2450,8 +2450,19 @@ void netmap_uninit_bridges(void);
 #define CSB_READ(csb, field, r) (get_user(r, &csb->field))
 #define CSB_WRITE(csb, field, v) (put_user(v, &csb->field))
 #else  /* ! linux */
-#define CSB_READ(csb, field, r) (r = fuword32(&csb->field))
-#define CSB_WRITE(csb, field, v) (suword32(&csb->field, v))
+#define CSB_READ(csb, field, r) do {				\
+	int32_t v __diagused;					\
+								\
+	v = fuword32(&csb->field);				\
+	KASSERT(v != -1, ("%s: fuword32 failed", __func__));	\
+	r = v;							\
+} while (0)
+#define CSB_WRITE(csb, field, v) do {				\
+	int error __diagused;					\
+								\
+	error = suword32(&csb->field, v);			\
+	KASSERT(error == 0, ("%s: suword32 failed", __func__));	\
+} while (0)
 #endif /* ! linux */
 
 /* some macros that may not be defined */