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| author | John Ogness <john.ogness@linutronix.de> | 2022-11-16 17:27:28 +0106 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2022-12-02 11:25:00 +0100 |
| commit | eb7f1ed2509c6223d960a7d69644a8eb506b13d0 (patch) | |
| tree | ecd6a939f5050316b7ecf741d188d283f3886138 /kernel/printk | |
| parent | fc956ae0de7fa25f99114609f21b76e7d38dc25c (diff) | |
| download | linux-eb7f1ed2509c6223d960a7d69644a8eb506b13d0.tar.gz | |
printk: __pr_flush: use srcu console list iterator
Use srcu console list iteration for console list traversal.
Document why the console_lock is still necessary. Note that this
is a preparatory change for when console_lock no longer provides
synchronization for the console list.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-17-john.ogness@linutronix.de
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/printk.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 13bc960c7aa53..abdbd3ffb0684 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3561,6 +3561,7 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre struct console *c; u64 last_diff = 0; u64 printk_seq; + int cookie; u64 diff; u64 seq; @@ -3571,9 +3572,15 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre for (;;) { diff = 0; + /* + * Hold the console_lock to guarantee safe access to + * console->seq and to prevent changes to @console_suspended + * until all consoles have been processed. + */ console_lock(); - for_each_console(c) { + cookie = console_srcu_read_lock(); + for_each_console_srcu(c) { if (con && con != c) continue; if (!console_is_usable(c)) @@ -3582,6 +3589,7 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre if (printk_seq < seq) diff += seq - printk_seq; } + console_srcu_read_unlock(cookie); /* * If consoles are suspended, it cannot be expected that they |