linux-kernel - [PATCH v2 17/28] vsprintf: Refactor mac_address

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Date:   Thu, 19 May 2022 13:24:10 -0400
From:   Kent Overstreet <kent.overstreet@...il.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...r.kernel.org,
        pmladek@...e.com, rostedt@...dmis.org, senozhatsky@...omium.org
Cc:     Kent Overstreet <kent.overstreet@...il.com>,
        andriy.shevchenko@...ux.intel.com, willy@...radead.org
Subject: [PATCH v2 17/28] vsprintf: Refactor mac_address_string()

 - We're attempting to consolidate printf_spec and format string
   handling in the top level vpr_buf(), this changes mac_address_string() to
   not take printf_spec

 - With the new printbuf helpers there's no need to use a separate stack
   allocated buffer, so this patch deletes it.

Signed-off-by: Kent Overstreet <kent.overstreet@...il.com>
---
 lib/vsprintf.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 62a221522c..76947e0d30 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1233,15 +1233,13 @@ void bitmap_list_string(struct printbuf *out, unsigned long *bitmap,
 
 static noinline_for_stack
 void mac_address_string(struct printbuf *out, u8 *addr,
-			struct printf_spec spec, const char *fmt)
+			const char *fmt)
 {
-	char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
-	char *p = mac_addr;
 	int i;
 	char separator;
 	bool reversed = false;
 
-	if (check_pointer_spec(out, addr, spec))
+	if (check_pointer(out, addr))
 		return;
 
 	switch (fmt[1]) {
@@ -1260,16 +1258,13 @@ void mac_address_string(struct printbuf *out, u8 *addr,
 
 	for (i = 0; i < 6; i++) {
 		if (reversed)
-			p = hex_byte_pack(p, addr[5 - i]);
+			pr_hex_byte(out, addr[5 - i]);
 		else
-			p = hex_byte_pack(p, addr[i]);
+			pr_hex_byte(out, addr[i]);
 
 		if (fmt[0] == 'M' && i != 5)
-			*p++ = separator;
+			pr_char(out, separator);
 	}
-	*p = '\0';
-
-	string_nocheck(out, mac_addr, spec);
 }
 
 static noinline_for_stack
@@ -2270,7 +2265,8 @@ void pointer(struct printbuf *out, const char *fmt,
 	case 'm':			/* Contiguous: 000102030405 */
 					/* [mM]F (FDDI) */
 					/* [mM]R (Reverse order; Bluetooth) */
-		return mac_address_string(out, ptr, spec, fmt);
+		mac_address_string(out, ptr, fmt);
+		return do_width_precision(out, prev_pos, spec);
 	case 'I':			/* Formatted IP supported
 					 * 4:	1.2.3.4
 					 * 6:	0001:0203:...:0708
-- 
2.36.0