[PATCH 5.18 879/879] tty: n_gsm: Fix packet data hex dump output

Greg Kroah-Hartman
2022-06-08T02:14:36Z

From: Tony Lindgren <tony@atomide.com>

commit 925ea0fa5277c1e6bb9e51955ef34eea9736c3d7 upstream.

The module param debug for n_gsm uses KERN_INFO level, but the hexdump
now uses KERN_DEBUG level. This started after commit 091cb0994edd
("lib/hexdump: make print_hex_dump_bytes() a nop on !DEBUG builds").
We now use dynamic_hex_dump() unless DEBUG is set.

This causes no packets to be seen with modprobe n_gsm debug=0x1f unlike
earlier. Let's fix this by adding gsm_hex_dump_bytes() that calls
print_hex_dump() with KERN_INFO to match what n_gsm is doing with the
other debug related output.

Fixes: 091cb0994edd ("lib/hexdump: make print_hex_dump_bytes() a nop on !DEBUG builds")
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20220512131506.1216-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/n_gsm.c | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)

--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -444,6 +444,25 @@ static u8 gsm_encode_modem(const struct
return modembits;
}

+static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
+ unsigned long len)
+{
+ char *prefix;
+
+ if (!fname) {
+ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len,
+ true);
+ return;
+ }
+
+ prefix = kasprintf(GFP_KERNEL, "%s: ", fname);
+ if (!prefix)
+ return;
+ print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
+ true);
+ kfree(prefix);
+}
+
/**
* gsm_print_packet - display a frame for debug
* @hdr: header to print before decode
@@ -508,7 +527,7 @@ static void gsm_print_packet(const char
else
pr_cont("(F)");

- print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
+ gsm_hex_dump_bytes(NULL, data, dlen);
}

@@ -698,9 +717,7 @@ static void gsm_data_kick(struct gsm_mux
}

if (debug & 4)
- print_hex_dump_bytes("gsm_data_kick: ",
- DUMP_PREFIX_OFFSET,
- gsm->txframe, len);
+ gsm_hex_dump_bytes(__func__, gsm->txframe, len);
if (gsmld_output(gsm, gsm->txframe, len) <= 0)
break;
/* FIXME: Can eliminate one SOF in many more cases */
@@ -2448,8 +2465,7 @@ static int gsmld_output(struct gsm_mux *
return -ENOSPC;
}
if (debug & 4)
- print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
- data, len);
+ gsm_hex_dump_bytes(__func__, data, len);
return gsm->tty->ops->write(gsm->tty, data, len);
}

@@ -2525,8 +2541,7 @@ static void gsmld_receive_buf(struct tty
char flags = TTY_NORMAL;

if (debug & 4)
- print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
- cp, count);
+ gsm_hex_dump_bytes(__func__, cp, count);

for (; count; count--, cp++) {
if (fp)