git: 3c3a20199ac9 - stable/15 - netmap: silence -Wdefault-const-init-field-unsafe warning

The branch stable/15 has been updated by dim:

URL: https://cgit.FreeBSD.org/src/commit/?id=3c3a20199ac9ef10f2bd90c0bd6e1c862578ab0d

commit 3c3a20199ac9ef10f2bd90c0bd6e1c862578ab0d
Author:     Alex Richardson <arichardson@FreeBSD.org>
AuthorDate: 2025-12-16 18:09:57 +0000
Commit:     Dimitry Andric <dim@FreeBSD.org>
CommitDate: 2026-05-27 21:41:03 +0000

    netmap: silence -Wdefault-const-init-field-unsafe warning
    
    The netmap_ring struct starts with various const members and rencent
    clang warns about leaving them uninitialized. Having them const in the
    first place is highly suspicious since they are updated with various
    macros but using hand-coded __DECONST(). But fixing that is a more
    invasive change that I am unable to test.
    
    ```
    .../freebsd/sys/dev/netmap/netmap_kloop.c:320:21: error: default initialization of an object of type 'struct netmap_ring' with const member leaves the object uninitialized [-Werror,-Wdefault-const-init-field-unsafe]
      320 |         struct netmap_ring shadow_ring; /* shadow copy of the netmap_ring */
          |                            ^
    .../freebsd/sys/net/netmap.h:290:16: note: member 'buf_ofs' declared 'const' here
      290 |         const int64_t   buf_ofs;
          |                         ^
    ```
    
    Test Plan: Compiles
    
    Reviewed by:    vmaffione, jhb
    MFC after:      1 week
    Differential Revision: https://reviews.freebsd.org/D52568
    
    (cherry picked from commit 2ed21f90906b230476d3f12ff9dce0e2c4642af2)
---
 sys/dev/netmap/netmap_kloop.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sys/dev/netmap/netmap_kloop.c b/sys/dev/netmap/netmap_kloop.c
index ba9e67076e72..ac3ca2d8d21f 100644
--- a/sys/dev/netmap/netmap_kloop.c
+++ b/sys/dev/netmap/netmap_kloop.c
@@ -161,7 +161,8 @@ netmap_sync_kloop_tx_ring(const struct sync_kloop_ring_args *a)
 	struct netmap_kring *kring = a->kring;
 	struct nm_csb_atok *csb_atok = a->csb_atok;
 	struct nm_csb_ktoa *csb_ktoa = a->csb_ktoa;
-	struct netmap_ring shadow_ring; /* shadow copy of the netmap_ring */
+	/* shadow copy of the netmap_ring */
+	struct netmap_ring shadow_ring = {0};
 #ifdef SYNC_KLOOP_POLL
 	bool more_txspace = false;
 #endif /* SYNC_KLOOP_POLL */
@@ -317,7 +318,8 @@ netmap_sync_kloop_rx_ring(const struct sync_kloop_ring_args *a)
 	struct netmap_kring *kring = a->kring;
 	struct nm_csb_atok *csb_atok = a->csb_atok;
 	struct nm_csb_ktoa *csb_ktoa = a->csb_ktoa;
-	struct netmap_ring shadow_ring; /* shadow copy of the netmap_ring */
+	/* shadow copy of the netmap_ring */
+	struct netmap_ring shadow_ring = {0};
 	int dry_cycles = 0;
 #ifdef SYNC_KLOOP_POLL
 	bool some_recvd = false;