linux-kernel - [PATCH v2] ipmi: use %*ph to print small buffer

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Message-Id: <20191011155036.36748-1-andriy.shevchenko@linux.intel.com>
Date:   Fri, 11 Oct 2019 18:50:36 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Corey Minyard <minyard@....org>,
        openipmi-developer@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Joe Perches <joe@...ches.com>
Cc:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v2] ipmi: use %*ph to print small buffer

From: Andy Shevchenko <andy.shevchenko@...il.com>

Use %*ph format to print small buffer as hex string.

The change is safe since the specifier can handle up to 64 bytes and taking
into account the buffer size of 100 bytes on stack the function has never been
used to dump more than 32 bytes. Note, this also avoids potential buffer
overflow if the length of the input buffer is bigger.

This completely eliminates ipmi_debug_msg() in favour of Dynamic Debug.

Signed-off-by: Andy Shevchenko <andy.shevchenko@...il.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
- eliminate ipmi_debug_msg() in favour of Dynamic Debug (Joe)
 drivers/char/ipmi/ipmi_msghandler.c | 27 ++++-----------------------
 1 file changed, 4 insertions(+), 23 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 2aab80e19ae0..1768b81aaf78 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -44,25 +44,6 @@ static void need_waiter(struct ipmi_smi *intf);
 static int handle_one_recv_msg(struct ipmi_smi *intf,
 			       struct ipmi_smi_msg *msg);
 
-#ifdef DEBUG
-static void ipmi_debug_msg(const char *title, unsigned char *data,
-			   unsigned int len)
-{
-	int i, pos;
-	char buf[100];
-
-	pos = snprintf(buf, sizeof(buf), "%s: ", title);
-	for (i = 0; i < len; i++)
-		pos += snprintf(buf + pos, sizeof(buf) - pos,
-				" %2.2x", data[i]);
-	pr_debug("%s\n", buf);
-}
-#else
-static void ipmi_debug_msg(const char *title, unsigned char *data,
-			   unsigned int len)
-{ }
-#endif
-
 static bool initialized;
 static bool drvregistered;
 
@@ -2267,7 +2248,7 @@ static int i_ipmi_request(struct ipmi_user     *user,
 		ipmi_free_smi_msg(smi_msg);
 		ipmi_free_recv_msg(recv_msg);
 	} else {
-		ipmi_debug_msg("Send", smi_msg->data, smi_msg->data_size);
+		pr_debug("Send: %*ph\n", smi_msg->data_size, smi_msg->data);
 
 		smi_send(intf, intf->handlers, smi_msg, priority);
 	}
@@ -3730,7 +3711,7 @@ static int handle_ipmb_get_msg_cmd(struct ipmi_smi *intf,
 		msg->data[10] = ipmb_checksum(&msg->data[6], 4);
 		msg->data_size = 11;
 
-		ipmi_debug_msg("Invalid command:", msg->data, msg->data_size);
+		pr_debug("Invalid command: %*ph\n", msg->data_size, msg->data);
 
 		rcu_read_lock();
 		if (!intf->in_shutdown) {
@@ -4217,7 +4198,7 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
 	int requeue;
 	int chan;
 
-	ipmi_debug_msg("Recv:", msg->rsp, msg->rsp_size);
+	pr_debug("Recv: %*ph\n", msg->rsp_size, msg->rsp);
 
 	if ((msg->data_size >= 2)
 	    && (msg->data[0] == (IPMI_NETFN_APP_REQUEST << 2))
@@ -4576,7 +4557,7 @@ smi_from_recv_msg(struct ipmi_smi *intf, struct ipmi_recv_msg *recv_msg,
 	smi_msg->data_size = recv_msg->msg.data_len;
 	smi_msg->msgid = STORE_SEQ_IN_MSGID(seq, seqid);
 
-	ipmi_debug_msg("Resend: ", smi_msg->data, smi_msg->data_size);
+	pr_debug("Resend: %*ph\n", smi_msg->data_size, smi_msg->data);
 
 	return smi_msg;
 }
-- 
2.23.0