diff options
author | Sergey Senozhatsky <sergey.senozhatsky@gmail.com> | 2018-10-02 11:38:34 +0900 |
---|---|---|
committer | Petr Mladek <pmladek@suse.com> | 2018-10-12 10:03:30 +0200 |
commit | 9627808d2d409279cea3fb334212d04a83ff6371 (patch) | |
tree | af946f325a2fade86a211620e3b5e32f1aaab4fb /kernel/printk/printk.c | |
parent | e6fe3e5b7d16e8f146a4ae7fe481bc6e97acde1e (diff) | |
download | linux-9627808d2d409279cea3fb334212d04a83ff6371.tar.bz2 |
printk: keep kernel cont support always enabled
Since commit 5c2992ee7fd8a29 ("printk: remove console flushing special
cases for partial buffered lines") we don't print cont fragments
to the consoles; cont lines are now proper log_buf entries and
there is no "consecutive continuation flag" anymore: we either
have 'c' entries that mark continuation lines without fragments;
or '-' entries that mark normal logbuf entries. There are no '+'
entries anymore.
However, we still have a small leftover - presence of ext_console
drivers disables kernel cont support and we flush each pr_cont()
and store it as a separate log_buf entry. Previously, it worked
because msg_print_ext_header() had that "an optional external merge
of the records" functionality:
if (msg->flags & LOG_CONT)
cont = (prev_flags & LOG_CONT) ? '+' : 'c';
We don't do this as of now, so keep kernel cont always enabled.
Note from pmladek:
The original purpose was to get full information including
the metadata and dictionary via extended console drivers,
see commit 6fe29354befe4c46e ("printk: implement support
for extended console drivers").
The dictionary probably was the most important part but
it was actually lost:
static void cont_flush(void)
{
[...]
log_store(cont.facility, cont.level, cont.flags, cont.ts_nsec,
NULL, 0, cont.buf, cont.len);
Nobody noticed because the only dictionary user is dev_printk()
and dev_cont() is _not_ defined.
Link: http://lkml.kernel.org/r/20181002023836.4487-2-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek@suse.com: Updated commit message]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'kernel/printk/printk.c')
-rw-r--r-- | kernel/printk/printk.c | 22 |
1 files changed, 4 insertions, 18 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index fce696d80e09..f717656c0fac 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -194,16 +194,7 @@ int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, return 0; } -/* - * Number of registered extended console drivers. - * - * If extended consoles are present, in-kernel cont reassembly is disabled - * and each fragment is stored as a separate log entry with proper - * continuation flag so that every emitted message has full metadata. This - * doesn't change the result for regular consoles or /proc/kmsg. For - * /dev/kmsg, as long as the reader concatenates messages according to - * consecutive continuation flags, the end result should be the same too. - */ +/* Number of registered extended console drivers. */ static int nr_ext_console_drivers; /* @@ -1781,12 +1772,8 @@ static void cont_flush(void) static bool cont_add(int facility, int level, enum log_flags flags, const char *text, size_t len) { - /* - * If ext consoles are present, flush and skip in-kernel - * continuation. See nr_ext_console_drivers definition. Also, if - * the line gets too long, split it up in separate records. - */ - if (nr_ext_console_drivers || cont.len + len > sizeof(cont.buf)) { + /* If the line gets too long, split it up in separate records. */ + if (cont.len + len > sizeof(cont.buf)) { cont_flush(); return false; } @@ -2706,8 +2693,7 @@ void register_console(struct console *newcon) } if (newcon->flags & CON_EXTENDED) - if (!nr_ext_console_drivers++) - pr_info("continuation disabled due to ext consoles, expect more fragments in /dev/kmsg\n"); + nr_ext_console_drivers++; if (newcon->flags & CON_PRINTBUFFER) { /* |