linux-kernel - [PATCH v2 11/28] vsprintf: Lift pr_hex_bytes() out from hex

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Date:   Thu, 19 May 2022 13:24:04 -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 11/28] vsprintf: Lift pr_hex_bytes() out from hex_string()

This factors pr_hex_bytes(), a new printbuf-style helper, out from
hex_string and adds it to pretty-printers.c.

Signed-off-by: Kent Overstreet <kent.overstreet@...il.com>
---
 include/linux/pretty-printers.h |  1 +
 lib/pretty-printers.c           | 23 +++++++++++++++++++++++
 lib/vsprintf.c                  | 13 ++++---------
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/include/linux/pretty-printers.h b/include/linux/pretty-printers.h
index 2e8b6b4426..ded34622e8 100644
--- a/include/linux/pretty-printers.h
+++ b/include/linux/pretty-printers.h
@@ -4,6 +4,7 @@
 #ifndef _LINUX_PRETTY_PRINTERS_H
 #define _LINUX_PRETTY_PRINTERS_H
 
+void pr_hex_bytes(struct printbuf *, const u8 *, unsigned, unsigned);
 void pr_string_option(struct printbuf *, const char * const[], size_t);
 void pr_bitflags(struct printbuf *, const char * const[], u64);
 
diff --git a/lib/pretty-printers.c b/lib/pretty-printers.c
index d794648ef9..162e6865f9 100644
--- a/lib/pretty-printers.c
+++ b/lib/pretty-printers.c
@@ -4,6 +4,29 @@
 #include <linux/kernel.h>
 #include <linux/printbuf.h>
 
+/**
+ * pr_hex_bytes - Print a string of hex bytes, with optional separator
+ *
+ * @out: The printbuf to output to
+ * @addr: Buffer to print
+ * @nr: Number of bytes to print
+ * @separator: Optional separator character between each byte
+ */
+void pr_hex_bytes(struct printbuf *out, const u8 *addr,
+		  unsigned nr, unsigned separator)
+{
+	unsigned i;
+
+	for (i = 0; i < nr; ++i) {
+		if (separator && i)
+			pr_char(out, separator);
+		pr_hex_byte(out, addr[i]);
+	}
+
+	printbuf_nul_terminate(out);
+}
+EXPORT_SYMBOL(pr_hex_bytes);
+
 /**
  * pr_string_option - Given a list of strings, print out the list and indicate
  * which option is selected, with square brackets (sysfs style)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 3f5638d27a..d4293b4a40 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -52,6 +52,7 @@
 #include <asm/byteorder.h>	/* cpu_to_le16 */
 
 #include <linux/string_helpers.h>
+#include <linux/pretty-printers.h>
 #include "kstrtox.h"
 
 static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base)
@@ -1107,10 +1108,10 @@ void resource_string(struct printbuf *out, struct resource *res,
 }
 
 static noinline_for_stack
-void hex_string(struct printbuf *out, u8 *addr,
+void hex_string(struct printbuf *out, const u8 *addr,
 		struct printf_spec spec, const char *fmt)
 {
-	int i, len = 1;		/* if we pass '%ph[CDN]', field width remains
+	int len = 1;		/* if we pass '%ph[CDN]', field width remains
 				   negative value, fallback to the default */
 	char separator;
 
@@ -1139,13 +1140,7 @@ void hex_string(struct printbuf *out, u8 *addr,
 	if (spec.field_width > 0)
 		len = min_t(int, spec.field_width, 64);
 
-	for (i = 0; i < len; ++i) {
-		__pr_char(out, hex_asc_hi(addr[i]));
-		__pr_char(out, hex_asc_lo(addr[i]));
-
-		if (separator && i != len - 1)
-			__pr_char(out, separator);
-	}
+	pr_hex_bytes(out, addr, len, separator);
 }
 
 static noinline_for_stack
-- 
2.36.0