[PATCH next v3 11/15] printk: kmsg_dumper: remove @active field

[John Ogness]

All 6 kmsg_dumpers do not benefit from the @active flag:

  (provide their own synchronization)
  - arch/powerpc/kernel/nvram_64.c
  - arch/um/kernel/kmsg_dump.c
  - drivers/mtd/mtdoops.c
  - fs/pstore/platform.c

  (only dump on KMSG_DUMP_PANIC, which does not require
  synchronization)
  - arch/powerpc/platforms/powernv/opal-kmsg.c
  - drivers/hv/vmbus_drv.c

The other 2 kmsg_dump users also do not rely on @active:

  (hard-code @active to always be true)
  - arch/powerpc/xmon/xmon.c
  - kernel/debug/kdb/kdb_main.c

Therefore, @active can be removed.

Signed-off-by: John Ogness <john.ogn...@linutronix.de>
---
 arch/powerpc/xmon/xmon.c    |  2 +-
 include/linux/kmsg_dump.h   |  2 --
 kernel/debug/kdb/kdb_main.c |  2 +-
 kernel/printk/printk.c      | 10 +---------
 4 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 3fe37495f63d..80ed3e1becf9 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -3001,7 +3001,7 @@ print_address(unsigned long addr)
 static void
 dump_log_buf(void)
 {
-       struct kmsg_dumper dumper = { .active = 1 };
+       struct kmsg_dumper dumper;
        unsigned char buf[128];
        size_t len;
 
diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 070c994ff19f..84eaa2090efa 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -36,7 +36,6 @@ enum kmsg_dump_reason {
  *             through the record iterator
  * @max_reason:        filter for highest reason number that should be dumped
  * @registered:        Flag that specifies if this is already registered
- * @active:    Flag that specifies if this is currently dumping
  * @cur_seq:   Points to the oldest message to dump
  * @next_seq:  Points after the newest message to dump
  */
@@ -44,7 +43,6 @@ struct kmsg_dumper {
        struct list_head list;
        void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
        enum kmsg_dump_reason max_reason;
-       bool active;
        bool registered;
 
        /* private state of the kmsg iterator */
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 930ac1b25ec7..315169d5e119 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2101,7 +2101,7 @@ static int kdb_dmesg(int argc, const char **argv)
        int adjust = 0;
        int n = 0;
        int skip = 0;
-       struct kmsg_dumper dumper = { .active = 1 };
+       struct kmsg_dumper dumper;
        size_t len;
        char buf[201];
 
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index c2ed7db8930b..45cb3e9c62c5 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3408,8 +3408,6 @@ void kmsg_dump(enum kmsg_dump_reason reason)
                        continue;
 
                /* initialize iterator with data about the stored records */
-               dumper->active = true;
-
                logbuf_lock_irqsave(flags);
                dumper->cur_seq = latched_seq_read_nolock(&clear_seq);
                dumper->next_seq = prb_next_seq(prb);
@@ -3417,9 +3415,6 @@ void kmsg_dump(enum kmsg_dump_reason reason)
 
                /* invoke dumper which will iterate over records */
                dumper->dump(dumper, reason);
-
-               /* reset iterator */
-               dumper->active = false;
        }
        rcu_read_unlock();
 }
@@ -3454,9 +3449,6 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper 
*dumper, bool syslog,
 
        prb_rec_init_rd(&r, &info, line, size);
 
-       if (!dumper->active)
-               goto out;
-
        /* Read text or count text lines? */
        if (line) {
                if (!prb_read_valid(prb, dumper->cur_seq, &r))
@@ -3542,7 +3534,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, 
bool syslog,
        bool ret = false;
        bool time = printk_time;
 
-       if (!dumper->active || !buf || !size)
+       if (!buf || !size)
                goto out;
 
        logbuf_lock_irqsave(flags);
-- 
2.20.1