git: 636bb42e6c55 - stable/14 - LinuxKPI: 802.11: deal with the error paths for lkpi_xmit()

The branch stable/14 has been updated by bz:

URL: https://cgit.FreeBSD.org/src/commit/?id=636bb42e6c5556beb8a79541cf0d60c0832450c9

commit 636bb42e6c5556beb8a79541cf0d60c0832450c9
Author:     Bjoern A. Zeeb <bz@FreeBSD.org>
AuthorDate: 2025-04-13 16:59:56 +0000
Commit:     Bjoern A. Zeeb <bz@FreeBSD.org>
CommitDate: 2025-04-18 14:36:02 +0000

    LinuxKPI: 802.11: deal with the error paths for lkpi_xmit()
    
    Rename lkpi_ic_raw_xmit() to lkpi_xmit() as we need a wrapper to add
    an extra argument as (*ic_raw_xmit) and (*ic_transmit) have different
    invariants.  Based on the caller free the mbuf in the error case or
    not to satisfy the requirements of the caller.  For more information
    see the comment in the code.
    
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit 9a45c3ca850110c5871742fadbf7355c1085c725)
---
 sys/compat/linuxkpi/common/src/linux_80211.c | 44 ++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 9 deletions(-)

diff --git a/sys/compat/linuxkpi/common/src/linux_80211.c b/sys/compat/linuxkpi/common/src/linux_80211.c
index a5f22046b55c..19ad12d73d12 100644
--- a/sys/compat/linuxkpi/common/src/linux_80211.c
+++ b/sys/compat/linuxkpi/common/src/linux_80211.c
@@ -4514,9 +4514,20 @@ lkpi_ic_node_free(struct ieee80211_node *ni)
 		lhw->ic_node_free(ni);
 }
 
+/*
+ * lkpi_xmit() called from both the (*ic_raw_xmit) as well as the (*ic_transmit)
+ * call path.
+ * Unfortunately they have slightly different invariants.  See
+ * ieee80211_raw_output() and ieee80211_parent_xmitpkt().
+ * Both take care of the ni reference in case of error, and otherwise during
+ * the callback after transmit.
+ * The difference is that in case of error (*ic_raw_xmit) needs us to release
+ * the mbuf, while (*ic_transmit) will free the mbuf itself.
+ */
 static int
-lkpi_ic_raw_xmit(struct ieee80211_node *ni, struct mbuf *m,
-        const struct ieee80211_bpf_params *params __unused)
+lkpi_xmit(struct ieee80211_node *ni, struct mbuf *m,
+    const struct ieee80211_bpf_params *params __unused,
+    bool freem)
 {
 	struct lkpi_sta *lsta;
 
@@ -4533,16 +4544,24 @@ lkpi_ic_raw_xmit(struct ieee80211_node *ni, struct mbuf *m,
 	if (!lsta->txq_ready) {
 #endif
 		LKPI_80211_LSTA_TXQ_UNLOCK(lsta);
-		/*
-		 * Free the mbuf (do NOT release ni ref for the m_pkthdr.rcvif!
-		 * ieee80211_raw_output() does that in case of error).
-		 */
-		m_free(m);
+		if (freem)
+			m_free(m);
 		return (ENETDOWN);
 	}
 
 	/* Queue the packet and enqueue the task to handle it. */
-	mbufq_enqueue(&lsta->txq, m);
+	error = mbufq_enqueue(&lsta->txq, m);
+	if (error != 0) {
+		LKPI_80211_LSTA_TXQ_UNLOCK(lsta);
+		if (freem)
+			m_free(m);
+#ifdef LINUXKPI_DEBUG_80211
+		if (linuxkpi_debug_80211 & D80211_TRACE_TX)
+			ic_printf(ni->ni_ic, "%s: mbufq_enqueue failed: %d\n",
+			    __func__, error);
+#endif
+		return (ENETDOWN);
+	}
 	taskqueue_enqueue(taskqueue_thread, &lsta->txq_task);
 	LKPI_80211_LSTA_TXQ_UNLOCK(lsta);
 
@@ -4556,6 +4575,13 @@ lkpi_ic_raw_xmit(struct ieee80211_node *ni, struct mbuf *m,
 	return (0);
 }
 
+static int
+lkpi_ic_raw_xmit(struct ieee80211_node *ni, struct mbuf *m,
+        const struct ieee80211_bpf_params *params __unused)
+{
+	return (lkpi_xmit(ni, m, NULL, true));
+}
+
 #ifdef LKPI_80211_HW_CRYPTO
 static int
 lkpi_hw_crypto_prepare(struct lkpi_sta *lsta, struct ieee80211_key *k,
@@ -4914,7 +4940,7 @@ lkpi_ic_transmit(struct ieee80211com *ic, struct mbuf *m)
 	struct ieee80211_node *ni;
 
 	ni = (struct ieee80211_node *)m->m_pkthdr.rcvif;
-	return (lkpi_ic_raw_xmit(ni, m, NULL));
+	return (lkpi_xmit(ni, m, NULL, false));
 }
 
 #ifdef LKPI_80211_HT