ihex: Share code between ihex_validate_fw() and ihex_next_binrec()

This change “ihex: Share code between ihex_validate_fw() and ihex_next_binrec()” in Linux kernel is authored by Andrey Smirnov <andrew.smirnov [at] gmail.com> on Thu Dec 20 23:28:37 2018 -0800.

ihex: Share code between ihex_validate_fw() and ihex_next_binrec()

Convert both ihex_validate_fw() and ihex_next_binrec() to use a helper
function to calculate next record offest. This way we only have one
place implementing next record offset calculation logic. No functional
change intended.

Cc: Chris Healy <cphealy@gmail.com>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit 8092e79.

There are 21 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 include/linux/ihex.h | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/linux/ihex.h b/include/linux/ihex.h
index 75c1943..9c70152 100644
--- a/include/linux/ihex.h
+++ b/include/linux/ihex.h
@@ -23,29 +23,34 @@ struct ihex_binrec {
 
 /* Find the next record, taking into account the 4-byte alignment */
 static inline const struct ihex_binrec *
-ihex_next_binrec(const struct ihex_binrec *rec)
+__ihex_next_binrec(const struct ihex_binrec *rec)
 {
 	int next = ((be16_to_cpu(rec->len) + 5) & ~3) - 2;
 	rec = (void *)&rec->data[next];
 
+	return rec;
+}
+
+static inline const struct ihex_binrec *
+ihex_next_binrec(const struct ihex_binrec *rec)
+{
+	rec = __ihex_next_binrec(rec);
+
 	return be16_to_cpu(rec->len) ? rec : NULL;
 }
 
 /* Check that ihex_next_binrec() won't take us off the end of the image... */
 static inline int ihex_validate_fw(const struct firmware *fw)
 {
-	const struct ihex_binrec *rec;
-	size_t ofs = 0;
+	const struct ihex_binrec *end, *rec;
 
-	while (ofs <= fw->size - sizeof(*rec)) {
-		rec = (void *)&fw->data[ofs];
+	rec = (const void *)fw->data;
+	end = (const void *)&fw->data[fw->size - sizeof(*end)];
 
+	for (; rec <= end; rec = __ihex_next_binrec(rec)) {
 		/* Zero length marks end of records */
 		if (!be16_to_cpu(rec->len))
 			return 0;
-
-		/* Point to next record... */
-		ofs += (sizeof(*rec) + be16_to_cpu(rec->len) + 3) & ~3;
 	}
 	return -EINVAL;
 }

The commit for this change in Linux stable tree is 8092e79 (patch).

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