Merge branch 'ethtool_puts'

Justin Stitt says:

====================
ethtool: Add ethtool_puts()

This series aims to implement ethtool_puts() and send out a wave 1 of
conversions from ethtool_sprintf(). There's also a checkpatch patch
included to check for the cases listed below.

This was sparked from recent discussion here [1]

The conversions are used in cases where ethtool_sprintf() was being used
with just two arguments:
|       ethtool_sprintf(&data, buffer[i].name);
or when it's used with format string: "%s"
|       ethtool_sprintf(&data, "%s", buffer[i].name);
which both now become:
|       ethtool_puts(&data, buffer[i].name);

The first case commonly triggers a -Wformat-security warning with Clang
due to potential problems with format flags present in the strings [3].

The second is just a bit weird with a plain-ol' "%s".

Changes found with Cocci [4] and grep [5].

[1]: https://lore.kernel.org/all/202310141935.B326C9E@keescook/
[2]: https://lore.kernel.org/all/?q=dfb%3Aethtool_sprintf+AND+f%3Ajustinstitt
[3]: https://lore.kernel.org/all/202310101528.9496539BE@keescook/
[4]: (script authored by Kees w/ modifications from Joe)
@replace_2_args@
expression BUF;
expression VAR;
@@

-       ethtool_sprintf(BUF, VAR)
+       ethtool_puts(BUF, VAR)

@replace_3_args@
expression BUF;
expression VAR;
@@

-       ethtool_sprintf(BUF, "%s", VAR)
+       ethtool_puts(BUF, VAR)

-       ethtool_sprintf(&BUF, "%s", VAR)
+       ethtool_puts(&BUF, VAR)

[5]: $ rg "ethtool_sprintf\(\s*[^,)]+\s*,\s*[^,)]+\s*\)"

Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Changes in v5:
- updated documentation to include info about the lack of a trailing newline
  (Thanks Russell)
- rebased onto mainline
- Link to v4: https://lore.kernel.org/r/20231102-ethtool_puts_impl-v4-0-14e1e9278496@google.com

Changes in v4:
- update documentation to match:
  https://lore.kernel.org/all/20231028192511.100001-1-andrew@lunn.ch/

- Link to v3: https://lore.kernel.org/r/20231027-ethtool_puts_impl-v3-0-3466ac679304@google.com

Changes in v3:
- fix force_speed_maps merge conflict + formatting (thanks Vladimir)
- rebase onto net-next (thanks Andrew, Vladimir)
- change subject (thanks Vladimir)
- fix checkpatch formatting + implementation (thanks Joe)
- Link to v2: https://lore.kernel.org/r/20231026-ethtool_puts_impl-v2-0-0d67cbdd0538@google.com

Changes in v2:
- wrap lines better in replacement (thanks Joe, Kees)
- add --fix to checkpatch (thanks Joe)
- clean up checkpatch formatting (thanks Joe, et al.)
- rebase against next
- Link to v1: https://lore.kernel.org/r/20231025-ethtool_puts_impl-v1-0-6a53a93d3b72@google.com
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index c2bb74143eda..deb683d3360f 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -1061,6 +1061,19 @@ int ethtool_get_ts_info_by_layer(struct net_device *dev, struct ethtool_ts_info
  */
 extern __printf(2, 3) void ethtool_sprintf(u8 **data, const char *fmt, ...);
 
+/**
+ * ethtool_puts - Write string to ethtool string data
+ * @data: Pointer to a pointer to the start of string to update
+ * @str: String to write
+ *
+ * Write string to *data without a trailing newline. Update *data
+ * to point at start of next string.
+ *
+ * Prefer this function to ethtool_sprintf() when given only
+ * two arguments or if @fmt is just "%s".
+ */
+extern void ethtool_puts(u8 **data, const char *str);
+
 /* Link mode to forced speed capabilities maps */
 struct ethtool_forced_speed_map {
 	u32		speed;