[PATCH v4 05/12] seq_file: provide an analogue of print_hex_dump()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

The new seq_hex_dump() is a complete analogue of print_hex_dump().

We have few users of this functionality already. It allows to reduce their
codebase.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 fs/seq_file.c            | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/seq_file.h |  4 ++++
 2 files changed, 54 insertions(+)

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 3857b72..66c721f4 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/cred.h>
 #include <linux/mm.h>
+#include <linux/printk.h>
 
 #include <asm/uaccess.h>
 #include <asm/page.h>
@@ -794,6 +795,55 @@ void seq_pad(struct seq_file *m, char c)
 }
 EXPORT_SYMBOL(seq_pad);
 
+/* Analogue of print_hex_dump() */
+int seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
+		 int rowsize, int groupsize, const void *buf, size_t len,
+		 bool ascii)
+{
+	const u8 *ptr = buf;
+	int i, linelen, remaining = len;
+	int ret;
+
+	if (rowsize != 16 && rowsize != 32)
+		rowsize = 16;
+
+	for (i = 0; i < len; i += rowsize) {
+		linelen = min(remaining, rowsize);
+		remaining -= rowsize;
+
+		/* Prefix string */
+		ret = seq_printf(m, "%s", prefix_str);
+		if (ret < 0)
+			return ret;
+
+		/* Counter if asked */
+		if (prefix_type == DUMP_PREFIX_ADDRESS)
+			ret = seq_printf(m, "%p: ", ptr + i);
+		else if (prefix_type == DUMP_PREFIX_OFFSET)
+			ret = seq_printf(m, "%.8x: ", i);
+		if (ret < 0)
+			return ret;
+
+		/* Hex dump */
+		ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
+					 m->buf + m->count, m->size - m->count,
+					 ascii);
+		if (m->count + ret >= m->size) {
+			seq_set_overflow(m);
+			return -1;
+		}
+		m->count += ret;
+
+		/* EOL */
+		ret = seq_putc(m, '\n');
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(seq_hex_dump);
+
 struct list_head *seq_list_start(struct list_head *head, loff_t pos)
 {
 	struct list_head *lh;
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 52e0097..5de290c 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -107,6 +107,10 @@ int seq_write(struct seq_file *seq, const void *data, size_t len);
 __printf(2, 3) int seq_printf(struct seq_file *, const char *, ...);
 __printf(2, 0) int seq_vprintf(struct seq_file *, const char *, va_list args);
 
+int seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
+		 int rowsize, int groupsize, const void *buf, size_t len,
+		 bool ascii);
+
 int seq_path(struct seq_file *, const struct path *, const char *);
 int seq_dentry(struct seq_file *, struct dentry *, const char *);
 int seq_path_root(struct seq_file *m, const struct path *path,
-- 
2.1.0