Instead of update a per-console CON_SUSPENDED flag, use the console_list
locks to protect this flag. This is also applied to console_is_usable
functions, which now also checks if consoles_suspend is set.

Signed-off-by: Marcos Paulo de Souza <mpdeso...@suse.com>
---
 kernel/printk/internal.h |  7 ++++++-
 kernel/printk/nbcon.c    |  8 ++++----
 kernel/printk/printk.c   | 23 ++++++++++-------------
 3 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 
48a24e7b309db20fdd7419f7aeda68ea7c79fd80..752101904f44b13059b6a922519d88e24c9f32c0
 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -118,8 +118,12 @@ void nbcon_kthreads_wake(void);
  * which can also play a role in deciding if @con can be used to print
  * records.
  */
-static inline bool console_is_usable(struct console *con, short flags, bool 
use_atomic)
+static inline bool console_is_usable(struct console *con, short flags,
+                                    bool use_atomic, bool consoles_suspended)
 {
+       if (consoles_suspended)
+               return false;
+
        if (!(flags & CON_ENABLED))
                return false;
 
@@ -212,6 +216,7 @@ extern bool have_boot_console;
 extern bool have_nbcon_console;
 extern bool have_legacy_console;
 extern bool legacy_allow_panic_sync;
+extern bool consoles_suspended;
 
 /**
  * struct console_flush_type - Define available console flush methods
diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
index 
fd12efcc4aeda8883773d9807bc215f6e5cdf71a..72de12396e6f1bc5234acfdf6dcc393acf88d216
 100644
--- a/kernel/printk/nbcon.c
+++ b/kernel/printk/nbcon.c
@@ -1147,7 +1147,7 @@ static bool nbcon_kthread_should_wakeup(struct console 
*con, struct nbcon_contex
        cookie = console_srcu_read_lock();
 
        flags = console_srcu_read_flags(con);
-       if (console_is_usable(con, flags, false)) {
+       if (console_is_usable(con, flags, false, consoles_suspended)) {
                /* Bring the sequence in @ctxt up to date */
                ctxt->seq = nbcon_seq_read(con);
 
@@ -1206,7 +1206,7 @@ static int nbcon_kthread_func(void *__console)
 
                con_flags = console_srcu_read_flags(con);
 
-               if (console_is_usable(con, con_flags, false))
+               if (console_is_usable(con, con_flags, false, 
consoles_suspended))
                        backlog = nbcon_emit_one(&wctxt, false);
 
                console_srcu_read_unlock(cookie);
@@ -1584,7 +1584,7 @@ static void __nbcon_atomic_flush_pending(u64 stop_seq, 
bool allow_unsafe_takeove
                if (!(flags & CON_NBCON))
                        continue;
 
-               if (!console_is_usable(con, flags, true))
+               if (!console_is_usable(con, flags, true, consoles_suspended))
                        continue;
 
                if (nbcon_seq_read(con) >= stop_seq)
@@ -1795,7 +1795,7 @@ void nbcon_device_release(struct console *con)
         */
        cookie = console_srcu_read_lock();
        printk_get_console_flush_type(&ft);
-       if (console_is_usable(con, console_srcu_read_flags(con), true) &&
+       if (console_is_usable(con, console_srcu_read_flags(con), true, 
consoles_suspended) &&
            !ft.nbcon_offload &&
            prb_read_valid(prb, nbcon_seq_read(con), NULL)) {
                /*
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 
6d3cf488f4261a3dfd8809a5ab7164b218238c13..658acf92aa3d2a3d1e294b7e17e5ee96d8169afe
 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -241,7 +241,7 @@ int devkmsg_sysctl_set_loglvl(const struct ctl_table 
*table, int write,
 /**
  * console_list_lock - Lock the console list
  *
- * For console list or console->flags updates
+ * For console list, console->flags and consoles_suspended updates
  */
 void console_list_lock(void)
 {
@@ -383,6 +383,8 @@ bool other_cpu_in_panic(void)
  */
 static int console_locked;
 
+bool consoles_suspended;
+
 /*
  *     Array of consoles built from command line options (console=)
  */
@@ -2755,16 +2757,13 @@ MODULE_PARM_DESC(console_no_auto_verbose, "Disable 
console loglevel raise to hig
  */
 void console_suspend_all(void)
 {
-       struct console *con;
-
        if (!console_suspend_enabled)
                return;
        pr_info("Suspending console(s) (use no_console_suspend to debug)\n");
        pr_flush(1000, true);
 
        console_list_lock();
-       for_each_console(con)
-               console_srcu_write_flags(con, con->flags | CON_SUSPENDED);
+       consoles_suspended = true;
        console_list_unlock();
 
        /*
@@ -2779,14 +2778,12 @@ void console_suspend_all(void)
 void console_resume_all(void)
 {
        struct console_flush_type ft;
-       struct console *con;
 
        if (!console_suspend_enabled)
                return;
 
        console_list_lock();
-       for_each_console(con)
-               console_srcu_write_flags(con, con->flags & ~CON_SUSPENDED);
+       consoles_suspended = false;
        console_list_unlock();
 
        /*
@@ -3214,7 +3211,7 @@ static bool console_flush_all(bool do_cond_resched, u64 
*next_seq, bool *handove
                        if ((flags & CON_NBCON) && (ft.nbcon_atomic || 
ft.nbcon_offload))
                                continue;
 
-                       if (!console_is_usable(con, flags, !do_cond_resched))
+                       if (!console_is_usable(con, flags, !do_cond_resched, 
consoles_suspended))
                                continue;
                        any_usable = true;
 
@@ -3604,7 +3601,7 @@ static bool legacy_kthread_should_wakeup(void)
                if ((flags & CON_NBCON) && (ft.nbcon_atomic || 
ft.nbcon_offload))
                        continue;
 
-               if (!console_is_usable(con, flags, false))
+               if (!console_is_usable(con, flags, false, consoles_suspended))
                        continue;
 
                if (flags & CON_NBCON) {
@@ -4165,7 +4162,7 @@ static int unregister_console_locked(struct console 
*console)
 
        if (!console_is_registered_locked(console))
                res = -ENODEV;
-       else if (console_is_usable(console, console->flags, true))
+       else if (console_is_usable(console, console->flags, true, 
consoles_suspended))
                __pr_flush(console, 1000, true);
 
        /* Disable it unconditionally */
@@ -4445,8 +4442,8 @@ static bool __pr_flush(struct console *con, int 
timeout_ms, bool reset_on_progre
                         * that they make forward progress, so only increment
                         * @diff for usable consoles.
                         */
-                       if (!console_is_usable(c, flags, true) &&
-                           !console_is_usable(c, flags, false)) {
+                       if (!console_is_usable(c, flags, true, 
consoles_suspended) &&
+                           !console_is_usable(c, flags, false, 
consoles_suspended)) {
                                continue;
                        }
 

-- 
2.49.0


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