linux-kernel - [PATCH] tty: n_gsm: gsm_print_packet: use scnprintf to avoid pr

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Date:   Mon, 18 May 2020 10:50:15 -0700
From:   Joe Perches <joe@...ches.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Gregory CLEMENT <gregory.clement@...tlin.com>
Cc:     Jiri Slaby <jslaby@...e.com>, linux-kernel@...r.kernel.org,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: [PATCH] tty: n_gsm: gsm_print_packet: use scnprintf to avoid pr_cont

Use a temporary buffer to avoid multiple pr_cont uses.

Signed-off-by: Joe Perches <joe@...ches.com>
---

> > > Ugh, as I already applied this series, should I just revert them all, or
> > > are you going to send fix-ups on top of what I have applied instead?
> > 
> > I was about to send a new series, but I can just send fix-ups. It's up
> > to you.
> 
> fix-ups are less work for me :)

Perhaps use something like this instead?

It does increase object size a tiny bit.

 drivers/tty/n_gsm.c | 71 +++++++++++++++++++++++++++++++----------------------
 1 file changed, 42 insertions(+), 29 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 69200bd411f7..7d7820aeb57b 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -454,58 +454,71 @@ static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
  */
 
 static void gsm_print_packet(const char *hdr, int addr, int cr,
-					u8 control, const u8 *data, int dlen)
+			     u8 control, const u8 *data, int dlen)
 {
+	char buf[100];
+	char *p;
+	char *type;
+
 	if (!(debug & 1))
 		return;
 
-	pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
+	p = buf;
+	p += scnprintf(p, buf - p, "%s %d) %c: ", hdr, addr, "RC"[cr]);
 
 	switch (control & ~PF) {
 	case SABM:
-		pr_cont("SABM");
+		type = "SABM";
 		break;
 	case UA:
-		pr_cont("UA");
+		type = "UA";
 		break;
 	case DISC:
-		pr_cont("DISC");
+		type = "DISC";
 		break;
 	case DM:
-		pr_cont("DM");
+		type = "DM";
 		break;
 	case UI:
-		pr_cont("UI");
+		type = "UI";
 		break;
 	case UIH:
-		pr_cont("UIH");
+		type = "UIH";
 		break;
 	default:
-		if (!(control & 0x01)) {
-			pr_cont("I N(S)%d N(R)%d",
-				(control & 0x0E) >> 1, (control & 0xE0) >> 5);
-		} else switch (control & 0x0F) {
-			case RR:
-				pr_cont("RR(%d)", (control & 0xE0) >> 5);
-				break;
-			case RNR:
-				pr_cont("RNR(%d)", (control & 0xE0) >> 5);
-				break;
-			case REJ:
-				pr_cont("REJ(%d)", (control & 0xE0) >> 5);
-				break;
-			default:
-				pr_cont("[%02X]", control);
+		type = NULL;
+		break;
+	}
+
+	if (type) {
+		p += scnprintf(p, buf - p, "%s", type);
+	} else if (!(control & 0x01)) {
+		p += scnprintf(p, buf - p, "I N(S)%d N(R)%d",
+			       (control & 0x0E) >> 1, (control & 0xE0) >> 5);
+	} else {
+		switch (control & 0x0F) {
+		case RR:
+			p += scnprintf(p, buf - p, "RR(%d)",
+				       (control & 0xE0) >> 5);
+			break;
+		case RNR:
+			p += scnprintf(p, buf - p, "RNR(%d)",
+				       (control & 0xE0) >> 5);
+			break;
+		case REJ:
+			p += scnprintf(p, buf - p, "REJ(%d)",
+				       (control & 0xE0) >> 5);
+			break;
+		default:
+			p += scnprintf(p, buf - p, "[%02X]", control);
+			break;
 		}
 	}
 
-	if (control & PF)
-		pr_cont("(P)");
-	else
-		pr_cont("(F)");
+	p += scnprintf(p, buf - p, "(%c)", control & PF ? 'P' : 'F');
 
-	if (dlen)
-		print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
+	pr_info("%s\n", buf);
+	print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
 }