kernel/linux.git/include/linux/seq_buf.h, branch v6.19.11

tracing: Add trace_seq_pop() and seq_buf_pop()

2025-10-29T00:10:59+00:00

In order to allow an interface to remove an added character from the trace_seq and seq_buf descriptors, add helper functions trace_seq_pop() and seq_buf_pop(). Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Peter Zijlstra Cc: Namhyung Kim Cc: Takaya Saeki Cc: Tom Zanussi Cc: Thomas Gleixner Cc: Ian Rogers Cc: Douglas Raillard Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Adrian Hunter Cc: Ingo Molnar Link: https://lore.kernel.org/20251028231148.594898736@kernel.org Signed-off-by: Steven Rostedt (Google)

seq_buf: Mark binary printing functions with __printf() attribute

2025-03-28T12:37:11+00:00

Binary printing functions are using printf() type of format, and compiler is not happy about them as is: lib/seq_buf.c:162:17: error: function ‘seq_buf_bprintf’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format] Fix the compilation errors by adding __printf() attribute. Signed-off-by: Andy Shevchenko Reviewed-by: Kees Cook Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20250321144822.324050-2-andriy.shevchenko@linux.intel.com Signed-off-by: Petr Mladek

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: Make DECLARE_SEQ_BUF() usable

2024-01-18T14:22:02+00:00

Using the address operator on the array doesn't work: ./include/linux/seq_buf.h:27:27: error: initialization of ‘char *’ from incompatible pointer type ‘char (*)[128]’ [-Werror=incompatible-pointer-types] 27 | .buffer = &__ ## NAME ## _buffer, \ | ^ Apart from fixing that, we can improve DECLARE_SEQ_BUF() by using a compound literal to define the buffer array without attaching a name to it. This makes the macro a single statement, allowing constructs such as: static DECLARE_SEQ_BUF(my_seq_buf, MYSB_SIZE); to work as intended. Link: https://lkml.kernel.org/r/20240116-declare-seq-buf-fix-v1-1-915db4692f32@linux.ibm.com Cc: stable@vger.kernel.org Acked-by: Kees Cook Fixes: dcc4e5728eea ("seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()") Signed-off-by: Nathan Lynch 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)

seq_buf: fix a misleading comment

2023-10-20T20:51:06+00:00

The comment for seq_buf_has_overflowed() says that an overflow condition is marked by len == size, but that's not what the code is testing. Make the comment match reality. Link: https://lkml.kernel.org/r/87pm19kp0m.fsf@meer.lwn.net Fixes: 8cd709ae7658a ("tracing: Have seq_buf use full buffer") Signed-off-by: Jonathan Corbet 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)

seq_buf: Add seq_buf_terminate() API

2021-03-18T16:58:27+00:00

In the case that the seq_buf buffer needs to be printed directly, add a way to make sure that the buffer is safe to read by forcing a nul terminating character at the end of the string, or the last byte of the buffer if the string has overflowed. Signed-off-by: Steven Rostedt (VMware)