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Message-ID: <20250424165020.627193-23-corey@minyard.net>
Date: Thu, 24 Apr 2025 11:49:59 -0500
From: Corey Minyard <corey@...yard.net>
To: linux-kernel@...r.kernel.org,
openipmi-developer@...ts.sourceforge.net,
Rik van Riel <riel@...riel.com>
Cc: "Paul E . McKenney" <paulmck@...nel.org>,
Breno Leitao <leitao@...ian.org>,
Corey Minyard <corey@...yard.net>,
Corey Minyard <cminyard@...sta.com>
Subject: [PATCH 22/23] ipmi:msghandler: Export and fix panic messaging capability
Don't have the other users that do things at panic time (the watchdog)
do all this themselves, provide a function to do it.
Also, with the new design where most stuff happens at thread context,
a few things needed to be fixed to avoid doing locking in a panic
context.
Signed-off-by: Corey Minyard <cminyard@...sta.com>
---
drivers/char/ipmi/ipmi_msghandler.c | 50 ++++++++++++++++++-----------
include/linux/ipmi.h | 10 ++++++
2 files changed, 41 insertions(+), 19 deletions(-)
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 938c566624d9..ece6aa95fbb5 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -2284,6 +2284,7 @@ static int i_ipmi_request(struct ipmi_user *user,
{
struct ipmi_smi_msg *smi_msg;
struct ipmi_recv_msg *recv_msg;
+ int run_to_completion = READ_ONCE(intf->run_to_completion);
int rv = 0;
if (user) {
@@ -2317,7 +2318,8 @@ static int i_ipmi_request(struct ipmi_user *user,
}
}
- mutex_lock(&intf->users_mutex);
+ if (!run_to_completion)
+ mutex_lock(&intf->users_mutex);
if (intf->in_shutdown) {
rv = -ENODEV;
goto out_err;
@@ -2363,7 +2365,8 @@ static int i_ipmi_request(struct ipmi_user *user,
smi_send(intf, intf->handlers, smi_msg, priority);
}
- mutex_unlock(&intf->users_mutex);
+ if (!run_to_completion)
+ mutex_unlock(&intf->users_mutex);
out:
if (rv && user)
@@ -4559,7 +4562,7 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
&& (msg->data[1] == IPMI_SEND_MSG_CMD)
&& (msg->user_data == NULL)) {
- if (intf->in_shutdown)
+ if (intf->in_shutdown || intf->run_to_completion)
goto out;
/*
@@ -4631,6 +4634,9 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
*/
struct ipmi_recv_msg *recv_msg;
+ if (intf->run_to_completion)
+ goto out;
+
chan = msg->data[2] & 0x0f;
if (chan >= IPMI_MAX_CHANNELS)
/* Invalid channel number */
@@ -4653,6 +4659,9 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
&& (msg->rsp[1] == IPMI_GET_MSG_CMD)) {
struct ipmi_channel *chans;
+ if (intf->run_to_completion)
+ goto out;
+
/* It's from the receive queue. */
chan = msg->rsp[3] & 0xf;
if (chan >= IPMI_MAX_CHANNELS) {
@@ -4727,6 +4736,9 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
} else if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
&& (msg->rsp[1] == IPMI_READ_EVENT_MSG_BUFFER_CMD)) {
/* It's an asynchronous event. */
+ if (intf->run_to_completion)
+ goto out;
+
requeue = handle_read_event_rsp(intf, msg);
} else {
/* It's a response from the local BMC. */
@@ -4855,15 +4867,6 @@ static void smi_work(struct work_struct *t)
list_del(&msg->link);
- /*
- * I would like for this check (and user->destroyed)
- * to go away, but it's possible that an interface is
- * processing a message that belongs to the user while
- * the user is being deleted. When that response
- * comes back, it could be queued after the user is
- * destroyed. This is simpler than handling it in the
- * interface.
- */
if (refcount_read(&user->destroyed) == 0) {
ipmi_free_recv_msg(msg);
} else {
@@ -5222,9 +5225,9 @@ static void dummy_recv_done_handler(struct ipmi_recv_msg *msg)
/*
* Inside a panic, send a message and wait for a response.
*/
-static void ipmi_panic_request_and_wait(struct ipmi_smi *intf,
- struct ipmi_addr *addr,
- struct kernel_ipmi_msg *msg)
+static void _ipmi_panic_request_and_wait(struct ipmi_smi *intf,
+ struct ipmi_addr *addr,
+ struct kernel_ipmi_msg *msg)
{
struct ipmi_smi_msg smi_msg;
struct ipmi_recv_msg recv_msg;
@@ -5254,6 +5257,15 @@ static void ipmi_panic_request_and_wait(struct ipmi_smi *intf,
ipmi_poll(intf);
}
+void ipmi_panic_request_and_wait(struct ipmi_user *user,
+ struct ipmi_addr *addr,
+ struct kernel_ipmi_msg *msg)
+{
+ user->intf->run_to_completion = 1;
+ _ipmi_panic_request_and_wait(user->intf, addr, msg);
+}
+EXPORT_SYMBOL(ipmi_panic_request_and_wait);
+
static void event_receiver_fetcher(struct ipmi_smi *intf,
struct ipmi_recv_msg *msg)
{
@@ -5322,7 +5334,7 @@ static void send_panic_events(struct ipmi_smi *intf, char *str)
}
/* Send the event announcing the panic. */
- ipmi_panic_request_and_wait(intf, &addr, &msg);
+ _ipmi_panic_request_and_wait(intf, &addr, &msg);
/*
* On every interface, dump a bunch of OEM event holding the
@@ -5358,7 +5370,7 @@ static void send_panic_events(struct ipmi_smi *intf, char *str)
msg.data = NULL;
msg.data_len = 0;
intf->null_user_handler = device_id_fetcher;
- ipmi_panic_request_and_wait(intf, &addr, &msg);
+ _ipmi_panic_request_and_wait(intf, &addr, &msg);
if (intf->local_event_generator) {
/* Request the event receiver from the local MC. */
@@ -5367,7 +5379,7 @@ static void send_panic_events(struct ipmi_smi *intf, char *str)
msg.data = NULL;
msg.data_len = 0;
intf->null_user_handler = event_receiver_fetcher;
- ipmi_panic_request_and_wait(intf, &addr, &msg);
+ _ipmi_panic_request_and_wait(intf, &addr, &msg);
}
intf->null_user_handler = NULL;
@@ -5419,7 +5431,7 @@ static void send_panic_events(struct ipmi_smi *intf, char *str)
memcpy_and_pad(data+5, 11, p, size, '\0');
p += size;
- ipmi_panic_request_and_wait(intf, &addr, &msg);
+ _ipmi_panic_request_and_wait(intf, &addr, &msg);
}
}
diff --git a/include/linux/ipmi.h b/include/linux/ipmi.h
index 27cd5980bb27..7da6602eab71 100644
--- a/include/linux/ipmi.h
+++ b/include/linux/ipmi.h
@@ -344,4 +344,14 @@ extern int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *data);
/* Helper function for computing the IPMB checksum of some data. */
unsigned char ipmb_checksum(unsigned char *data, int size);
+/*
+ * For things that must send messages at panic time, like the IPMI watchdog
+ * driver that extends the reset time on a panic, use this to send messages
+ * from panic context. Note that this puts the driver into a mode that
+ * only works at panic time, so only use it then.
+ */
+void ipmi_panic_request_and_wait(struct ipmi_user *user,
+ struct ipmi_addr *addr,
+ struct kernel_ipmi_msg *msg);
+
#endif /* __LINUX_IPMI_H */
--
2.43.0
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