linux.git/lib/seq_buf.c, branch v7.2-rc1

seq_buf: Export seq_buf_putmem_hex() and add KUnit tests

2026-05-21T22:03:06+00:00

The seq_buf KUnit suite does not exercise seq_buf_putmem_hex().

Add one test for the len > 8 chunking path and one overflow test
where a later chunk no longer fits in the buffer.

Export seq_buf_putmem_hex() as well so SEQ_BUF_KUNIT_TEST=m links
cleanly. Without the export, modpost reports seq_buf_putmem_hex as
undefined when seq_buf_kunit is built as a module.

Cc: Andrew Morton 
Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Cc: David Gow 
Link: https://patch.msgid.link/20260408202351.21829-1-shuvampandey1@gmail.com
Acked-by: Steven Rostedt (Google) 
Signed-off-by: Shuvam Pandey 
Signed-off-by: Steven Rostedt

seq_buf: Fix kernel documentation

2024-02-15T17:17:28+00:00

There are plenty of issues with the kernel documentation here:
  - misspelled word "sequence"
  - different style of returned value descriptions
  - missed Return sections
  - unaligned style of ASCII / NUL-terminated / etc
  - wrong function references

Fix all these.

Link: https://lkml.kernel.org/r/20240215152506.598340-1-andriy.shevchenko@linux.intel.com

Cc: Andrew Morton 
Signed-off-by: Andy Shevchenko 
Reviewed-by: Randy Dunlap 
Signed-off-by: Steven Rostedt (Google)

seq_buf: Don't use "proxy" headers

2024-02-15T17:16:46+00:00

Update header inclusions to follow IWYU (Include What You Use)
principle.

Link: https://lkml.kernel.org/r/20240215142255.400264-1-andriy.shevchenko@linux.intel.com

Cc: "Matthew Wilcox (Oracle)" 
Cc: Andrew Morton 
Signed-off-by: Andy Shevchenko 
Signed-off-by: Steven Rostedt (Google)

seq_buf: Export seq_buf_puts()

2023-11-02T04:19:44+00:00

Mark seq_buf_puts() which is part of the seq_buf API to be exported to
kernel loadable GPL modules.

Link: https://lkml.kernel.org/r/b9e3737f66ec2450221b492048ce0d9c65c84953.1698861216.git.christophe.jaillet@wanadoo.fr

Signed-off-by: Christophe JAILLET 
Signed-off-by: Steven Rostedt (Google)

seq_buf: Export seq_buf_putc()

2023-11-02T04:18:52+00:00

Mark seq_buf_putc() which is part of the seq_buf API to be exported to
kernel loadable GPL modules.

Link: https://lkml.kernel.org/r/5c9a5ed97ac37dbdcd9c1e7bcbdec9ac166e79be.1698861216.git.christophe.jaillet@wanadoo.fr

Signed-off-by: Christophe JAILLET 
Signed-off-by: Steven Rostedt (Google)

seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()

2023-10-28T20:52:43+00:00

Solve two ergonomic issues with struct seq_buf;

1) Too much boilerplate is required to initialize:

	struct seq_buf s;
	char buf[32];

	seq_buf_init(s, buf, sizeof(buf));

Instead, we can build this directly on the stack. Provide
DECLARE_SEQ_BUF() macro to do this:

	DECLARE_SEQ_BUF(s, 32);

2) %NUL termination is fragile and requires 2 steps to get a valid
   C String (and is a layering violation exposing the "internals" of
   seq_buf):

	seq_buf_terminate(s);
	do_something(s->buffer);

Instead, we can just return s->buffer directly after terminating it in
the refactored seq_buf_terminate(), now known as seq_buf_str():

	do_something(seq_buf_str(s));

Link: https://lore.kernel.org/linux-trace-kernel/20231027155634.make.260-kees@kernel.org
Link: https://lore.kernel.org/linux-trace-kernel/20231026194033.it.702-kees@kernel.org/

Cc: Yosry Ahmed 
Cc: "Matthew Wilcox (Oracle)" 
Cc: Christoph Hellwig 
Cc: Justin Stitt 
Cc: Kent Overstreet 
Cc: Petr Mladek 
Cc: Andy Shevchenko 
Cc: Rasmus Villemoes 
Cc: Sergey Senozhatsky 
Cc: Masami Hiramatsu 
Cc: Greg Kroah-Hartman 
Cc: Arnd Bergmann 
Cc: Jonathan Corbet 
Cc: Yun Zhou 
Cc: Jacob Keller 
Cc: Zhen Lei 
Signed-off-by: Kees Cook 
Signed-off-by: Steven Rostedt (Google)

tracing: Move readpos from seq_buf to trace_seq

2023-10-20T16:16:10+00:00

To make seq_buf more lightweight as a string buf, move the readpos member
from seq_buf to its container, trace_seq.  That puts the responsibility
of maintaining the readpos entirely in the tracing code.  If some future
users want to package up the readpos with a seq_buf, we can define a
new struct then.

Link: https://lore.kernel.org/linux-trace-kernel/20231020033545.2587554-2-willy@infradead.org

Cc: Kees Cook 
Cc: Justin Stitt 
Cc: Kent Overstreet 
Cc: Petr Mladek 
Cc: Andy Shevchenko 
Cc: Rasmus Villemoes 
Cc: Sergey Senozhatsky 
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Christoph Hellwig 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Steven Rostedt (Google)

seq_buf: Add seq_buf_do_printk() helper

2023-04-26T01:03:14+00:00

Sometimes we use seq_buf to format a string buffer, which
we then pass to printk(). However, in certain situations
the seq_buf string buffer can get too big, exceeding the
PRINTKRB_RECORD_MAX bytes limit, and causing printk() to
truncate the string.

Add a new seq_buf helper. This helper prints the seq_buf
string buffer line by line, using \n as a delimiter,
rather than passing the whole string buffer to printk()
at once.

Link: https://lkml.kernel.org/r/20230415100110.1419872-1-senozhatsky@chromium.org

Cc: Andrew Morton 
Signed-off-by: Sergey Senozhatsky 
Reviewed-by: Petr Mladek 
Tested-by: Yosry Ahmed 
Signed-off-by: Steven Rostedt (Google)

lib: fix spelling mistakes

2021-07-08T18:48:20+00:00

Fix some spelling mistakes in comments:
permanentely ==> permanently
wont ==> won't
remaning ==> remaining
succed ==> succeed
shouldnt ==> shouldn't
alpha-numeric ==> alphanumeric
storeing ==> storing
funtion ==> function
documenation ==> documentation
Determin ==> Determine
intepreted ==> interpreted
ammount ==> amount
obious ==> obvious
interupts ==> interrupts
occured ==> occurred
asssociated ==> associated
taking into acount ==> taking into account
squence ==> sequence
stil ==> still
contiguos ==> contiguous
matchs ==> matches

Link: https://lkml.kernel.org/r/20210607072555.12416-1-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei 
Reviewed-by: Jacob Keller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

seq_buf: Make trace_seq_putmem_hex() support data longer than 8

2021-06-26T13:19:16+00:00

Since the raw memory 'data' does not go forward, it will dump repeated
data if the data length is more than 8. If we want to dump longer data
blocks, we need to repeatedly call macro SEQ_PUT_HEX_FIELD. I think it
is a bit redundant, and multiple function calls also affect the performance.

Link: https://lore.kernel.org/lkml/20210625122453.5e2fe304@oasis.local.home/
Link: https://lkml.kernel.org/r/20210626032156.47889-2-yun.zhou@windriver.com

Cc: stable@vger.kernel.org
Fixes: 6d2289f3faa7 ("tracing: Make trace_seq_putmem_hex() more robust")
Signed-off-by: Yun Zhou 
Signed-off-by: Steven Rostedt (VMware)