x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 244 insertions, 0 deletions

diff --git a/drivers/media/firewire/firedtv-dvb.c b/drivers/media/firewire/firedtv-dvb.c
new file mode 100644
index 000000000..3b7e2f1ec
--- /dev/null
+++ b/drivers/media/firewire/firedtv-dvb.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * FireDTV driver (formerly known as FireSAT)
+ *
+ * Copyright (C) 2004 Andreas Monitzer <andy@monitzer.com>
+ * Copyright (C) 2008 Henrik Kurelid <henrik@kurelid.se>
+ */
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+#include <media/dmxdev.h>
+#include <media/dvb_demux.h>
+#include <media/dvbdev.h>
+#include <media/dvb_frontend.h>
+
+#include "firedtv.h"
+
+static int alloc_channel(struct firedtv *fdtv)
+{
+	int i;
+
+	for (i = 0; i < 16; i++)
+		if (!__test_and_set_bit(i, &fdtv->channel_active))
+			break;
+	return i;
+}
+
+static void collect_channels(struct firedtv *fdtv, int *pidc, u16 pid[])
+{
+	int i, n;
+
+	for (i = 0, n = 0; i < 16; i++)
+		if (test_bit(i, &fdtv->channel_active))
+			pid[n++] = fdtv->channel_pid[i];
+	*pidc = n;
+}
+
+static inline void dealloc_channel(struct firedtv *fdtv, int i)
+{
+	__clear_bit(i, &fdtv->channel_active);
+}
+
+int fdtv_start_feed(struct dvb_demux_feed *dvbdmxfeed)
+{
+	struct firedtv *fdtv = dvbdmxfeed->demux->priv;
+	int pidc, c, ret;
+	u16 pids[16];
+
+	switch (dvbdmxfeed->type) {
+	case DMX_TYPE_TS:
+	case DMX_TYPE_SEC:
+		break;
+	default:
+		dev_err(fdtv->device, "can't start dmx feed: invalid type %u\n",
+			dvbdmxfeed->type);
+		return -EINVAL;
+	}
+
+	if (mutex_lock_interruptible(&fdtv->demux_mutex))
+		return -EINTR;
+
+	if (dvbdmxfeed->type == DMX_TYPE_TS) {
+		switch (dvbdmxfeed->pes_type) {
+		case DMX_PES_VIDEO:
+		case DMX_PES_AUDIO:
+		case DMX_PES_TELETEXT:
+		case DMX_PES_PCR:
+		case DMX_PES_OTHER:
+			c = alloc_channel(fdtv);
+			break;
+		default:
+			dev_err(fdtv->device,
+				"can't start dmx feed: invalid pes type %u\n",
+				dvbdmxfeed->pes_type);
+			ret = -EINVAL;
+			goto out;
+		}
+	} else {
+		c = alloc_channel(fdtv);
+	}
+
+	if (c > 15) {
+		dev_err(fdtv->device, "can't start dmx feed: busy\n");
+		ret = -EBUSY;
+		goto out;
+	}
+
+	dvbdmxfeed->priv = (typeof(dvbdmxfeed->priv))(unsigned long)c;
+	fdtv->channel_pid[c] = dvbdmxfeed->pid;
+	collect_channels(fdtv, &pidc, pids);
+
+	if (dvbdmxfeed->pid == 8192) {
+		ret = avc_tuner_get_ts(fdtv);
+		if (ret) {
+			dealloc_channel(fdtv, c);
+			dev_err(fdtv->device, "can't get TS\n");
+			goto out;
+		}
+	} else {
+		ret = avc_tuner_set_pids(fdtv, pidc, pids);
+		if (ret) {
+			dealloc_channel(fdtv, c);
+			dev_err(fdtv->device, "can't set PIDs\n");
+			goto out;
+		}
+	}
+out:
+	mutex_unlock(&fdtv->demux_mutex);
+
+	return ret;
+}
+
+int fdtv_stop_feed(struct dvb_demux_feed *dvbdmxfeed)
+{
+	struct dvb_demux *demux = dvbdmxfeed->demux;
+	struct firedtv *fdtv = demux->priv;
+	int pidc, c, ret;
+	u16 pids[16];
+
+	if (dvbdmxfeed->type == DMX_TYPE_TS &&
+	    !((dvbdmxfeed->ts_type & TS_PACKET) &&
+	      (demux->dmx.frontend->source != DMX_MEMORY_FE))) {
+
+		if (dvbdmxfeed->ts_type & TS_DECODER) {
+			if (dvbdmxfeed->pes_type >= DMX_PES_OTHER ||
+			    !demux->pesfilter[dvbdmxfeed->pes_type])
+				return -EINVAL;
+
+			demux->pids[dvbdmxfeed->pes_type] |= 0x8000;
+			demux->pesfilter[dvbdmxfeed->pes_type] = NULL;
+		}
+
+		if (!(dvbdmxfeed->ts_type & TS_DECODER &&
+		      dvbdmxfeed->pes_type < DMX_PES_OTHER))
+			return 0;
+	}
+
+	if (mutex_lock_interruptible(&fdtv->demux_mutex))
+		return -EINTR;
+
+	c = (unsigned long)dvbdmxfeed->priv;
+	dealloc_channel(fdtv, c);
+	collect_channels(fdtv, &pidc, pids);
+
+	ret = avc_tuner_set_pids(fdtv, pidc, pids);
+
+	mutex_unlock(&fdtv->demux_mutex);
+
+	return ret;
+}
+
+DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
+
+int fdtv_dvb_register(struct firedtv *fdtv, const char *name)
+{
+	int err;
+
+	err = dvb_register_adapter(&fdtv->adapter, name,
+				   THIS_MODULE, fdtv->device, adapter_nr);
+	if (err < 0)
+		goto fail_log;
+
+	/*DMX_TS_FILTERING | DMX_SECTION_FILTERING*/
+	fdtv->demux.dmx.capabilities = 0;
+
+	fdtv->demux.priv	= fdtv;
+	fdtv->demux.filternum	= 16;
+	fdtv->demux.feednum	= 16;
+	fdtv->demux.start_feed	= fdtv_start_feed;
+	fdtv->demux.stop_feed	= fdtv_stop_feed;
+	fdtv->demux.write_to_decoder = NULL;
+
+	err = dvb_dmx_init(&fdtv->demux);
+	if (err)
+		goto fail_unreg_adapter;
+
+	fdtv->dmxdev.filternum    = 16;
+	fdtv->dmxdev.demux        = &fdtv->demux.dmx;
+	fdtv->dmxdev.capabilities = 0;
+
+	err = dvb_dmxdev_init(&fdtv->dmxdev, &fdtv->adapter);
+	if (err)
+		goto fail_dmx_release;
+
+	fdtv->frontend.source = DMX_FRONTEND_0;
+
+	err = fdtv->demux.dmx.add_frontend(&fdtv->demux.dmx, &fdtv->frontend);
+	if (err)
+		goto fail_dmxdev_release;
+
+	err = fdtv->demux.dmx.connect_frontend(&fdtv->demux.dmx,
+					       &fdtv->frontend);
+	if (err)
+		goto fail_rem_frontend;
+
+	err = dvb_net_init(&fdtv->adapter, &fdtv->dvbnet, &fdtv->demux.dmx);
+	if (err)
+		goto fail_disconnect_frontend;
+
+	fdtv_frontend_init(fdtv, name);
+	err = dvb_register_frontend(&fdtv->adapter, &fdtv->fe);
+	if (err)
+		goto fail_net_release;
+
+	err = fdtv_ca_register(fdtv);
+	if (err)
+		dev_info(fdtv->device,
+			 "Conditional Access Module not enabled\n");
+	return 0;
+
+fail_net_release:
+	dvb_net_release(&fdtv->dvbnet);
+fail_disconnect_frontend:
+	fdtv->demux.dmx.close(&fdtv->demux.dmx);
+fail_rem_frontend:
+	fdtv->demux.dmx.remove_frontend(&fdtv->demux.dmx, &fdtv->frontend);
+fail_dmxdev_release:
+	dvb_dmxdev_release(&fdtv->dmxdev);
+fail_dmx_release:
+	dvb_dmx_release(&fdtv->demux);
+fail_unreg_adapter:
+	dvb_unregister_adapter(&fdtv->adapter);
+fail_log:
+	dev_err(fdtv->device, "DVB initialization failed\n");
+	return err;
+}
+
+void fdtv_dvb_unregister(struct firedtv *fdtv)
+{
+	fdtv_ca_release(fdtv);
+	dvb_unregister_frontend(&fdtv->fe);
+	dvb_net_release(&fdtv->dvbnet);
+	fdtv->demux.dmx.close(&fdtv->demux.dmx);
+	fdtv->demux.dmx.remove_frontend(&fdtv->demux.dmx, &fdtv->frontend);
+	dvb_dmxdev_release(&fdtv->dmxdev);
+	dvb_dmx_release(&fdtv->demux);
+	dvb_unregister_adapter(&fdtv->adapter);
+}