ipmi: Fix __scan_channels() failing to rescan channels

channel_handler() sets intf->channels_ready to true but never
clears it, so __scan_channels() skips any rescan. When the BMC
firmware changes a rescan is required. Allow it by clearing
the flag before starting a new scan.

Signed-off-by: Jinhui Guo <guojinhui.liam@bytedance.com>
Message-ID: <20250930074239.2353-3-guojinhui.liam@bytedance.com>
Signed-off-by: Corey Minyard <corey@minyard.net>

Author: guojinhui-liam

drivers/char/ipmi/ipmi_msghandler.c

@@ -599,7 +599,8 @@ static void __ipmi_bmc_unregister(struct ipmi_smi *intf);
 static int __ipmi_bmc_register(struct ipmi_smi *intf,
 			       struct ipmi_device_id *id,
 			       bool guid_set, guid_t *guid, int intf_num);
-static int __scan_channels(struct ipmi_smi *intf, struct ipmi_device_id *id);
+static int __scan_channels(struct ipmi_smi *intf,
+				struct ipmi_device_id *id, bool rescan);
 
 static void free_ipmi_user(struct kref *ref)
 {
@@ -2668,7 +2669,7 @@ static int __bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc,
 		if (__ipmi_bmc_register(intf, &id, guid_set, &guid, intf_num))
 			need_waiter(intf); /* Retry later on an error. */
 		else
-			__scan_channels(intf, &id);
+			__scan_channels(intf, &id, false);
 
 
 		if (!intf_set) {
@@ -2688,7 +2689,7 @@ static int __bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc,
 		goto out_noprocessing;
 	} else if (memcmp(&bmc->fetch_id, &bmc->id, sizeof(bmc->id)))
 		/* Version info changes, scan the channels again. */
-		__scan_channels(intf, &bmc->fetch_id);
+		__scan_channels(intf, &bmc->fetch_id, true);
 
 	bmc->dyn_id_expiry = jiffies + IPMI_DYN_DEV_ID_EXPIRY;
 
@@ -3438,10 +3439,17 @@ channel_handler(struct ipmi_smi *intf, struct ipmi_recv_msg *msg)
 /*
  * Must be holding intf->bmc_reg_mutex to call this.
  */
-static int __scan_channels(struct ipmi_smi *intf, struct ipmi_device_id *id)
+static int __scan_channels(struct ipmi_smi *intf,
+				struct ipmi_device_id *id,
+				bool rescan)
 {
 	int rv;
 
+	if (rescan) {
+		/* Clear channels_ready to force channels rescan. */
+		intf->channels_ready = false;
+	}
+
 	if (ipmi_version_major(id) > 1
 			|| (ipmi_version_major(id) == 1
 			    && ipmi_version_minor(id) >= 5)) {
@@ -3656,7 +3664,7 @@ int ipmi_add_smi(struct module         *owner,
 	}
 
 	mutex_lock(&intf->bmc_reg_mutex);
-	rv = __scan_channels(intf, &id);
+	rv = __scan_channels(intf, &id, false);
 	mutex_unlock(&intf->bmc_reg_mutex);
 	if (rv)
 		goto out_err_bmc_reg;