printk: kmsg_dump: remove _nolock() variants

kmsg_dump_rewind() and kmsg_dump_get_line() are lockless, so there is
no need for _nolock() variants. Remove these functions and switch all
callers of the _nolock() variants.

The functions without _nolock() were chosen because they are already
exported to kernel modules.

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/20210303101528.29901-15-john.ogness@linutronix.de

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index dbcf403b1d8dec47601886042a78ce12eb0c07f3..dd0e0aac954e0a300c7a17cb376ee4e5ce87336e 100644 (file)
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -3017,9 +3017,9 @@ dump_log_buf(void)
        catch_memory_errors = 1;
        sync();
 
-       kmsg_dump_rewind_nolock(&iter);
+       kmsg_dump_rewind(&iter);
        xmon_start_pagination();
-       while (kmsg_dump_get_line_nolock(&iter, false, buf, sizeof(buf), &len)) {
+       while (kmsg_dump_get_line(&iter, false, buf, sizeof(buf), &len)) {
                buf[len] = '\0';
                printf("%s", buf);
        }

diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 36c8c57e10510ff88271f5cea149141c2a3ac53b..906521c2329caaeb8044ef6b6858a3527b4547c2 100644 (file)
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -57,17 +57,12 @@ struct kmsg_dumper {
 #ifdef CONFIG_PRINTK
 void kmsg_dump(enum kmsg_dump_reason reason);
 
-bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog,
-                              char *line, size_t size, size_t *len);
-
 bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog,
                        char *line, size_t size, size_t *len);
 
 bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog,
                          char *buf, size_t size, size_t *len_out);
 
-void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter);
-
 void kmsg_dump_rewind(struct kmsg_dump_iter *iter);
 
 int kmsg_dump_register(struct kmsg_dumper *dumper);
@@ -80,13 +75,6 @@ static inline void kmsg_dump(enum kmsg_dump_reason reason)
 {
 }
 
-static inline bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter,
-                                            bool syslog, const char *line,
-                                            size_t size, size_t *len)
-{
-       return false;
-}
-
 static inline bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog,
                                const char *line, size_t size, size_t *len)
 {
@@ -99,10 +87,6 @@ static inline bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog
        return false;
 }
 
-static inline void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter)
-{
-}
-
 static inline void kmsg_dump_rewind(struct kmsg_dump_iter *iter)
 {
 }

diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 8544d7a55a57bd9b5ddf9436e8748910041f9050..67d9f2403b52f304b275e1d4a41afd60f5236992 100644 (file)
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2126,8 +2126,8 @@ static int kdb_dmesg(int argc, const char **argv)
                kdb_set(2, setargs);
        }
 
-       kmsg_dump_rewind_nolock(&iter);
-       while (kmsg_dump_get_line_nolock(&iter, 1, NULL, 0, NULL))
+       kmsg_dump_rewind(&iter);
+       while (kmsg_dump_get_line(&iter, 1, NULL, 0, NULL))
                n++;
 
        if (lines < 0) {
@@ -2159,8 +2159,8 @@ static int kdb_dmesg(int argc, const char **argv)
        if (skip >= n || skip < 0)
                return 0;
 
-       kmsg_dump_rewind_nolock(&iter);
-       while (kmsg_dump_get_line_nolock(&iter, 1, buf, sizeof(buf), &len)) {
+       kmsg_dump_rewind(&iter);
+       while (kmsg_dump_get_line(&iter, 1, buf, sizeof(buf), &len)) {
                if (skip) {
                        skip--;
                        continue;

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 8994bc192b88cb3fb7053ae16211ff89fc2f43bf..602de86d4e767d5d3585f328b78ae8ba128533cf 100644 (file)
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3373,7 +3373,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
 }
 
 /**
- * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
+ * kmsg_dump_get_line - retrieve one kmsg log line
  * @iter: kmsg dump iterator
  * @syslog: include the "<4>" prefixes
  * @line: buffer to copy the line to
@@ -3388,22 +3388,22 @@ void kmsg_dump(enum kmsg_dump_reason reason)
  *
  * A return value of FALSE indicates that there are no more records to
  * read.
- *
- * The function is similar to kmsg_dump_get_line(), but grabs no locks.
  */
-bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog,
-                              char *line, size_t size, size_t *len)
+bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog,
+                       char *line, size_t size, size_t *len)
 {
        u64 min_seq = latched_seq_read_nolock(&clear_seq);
        struct printk_info info;
        unsigned int line_count;
        struct printk_record r;
+       unsigned long flags;
        size_t l = 0;
        bool ret = false;
 
        if (iter->cur_seq < min_seq)
                iter->cur_seq = min_seq;
 
+       printk_safe_enter_irqsave(flags);
        prb_rec_init_rd(&r, &info, line, size);
 
        /* Read text or count text lines? */
@@ -3424,40 +3424,11 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dump_iter *iter, bool syslog,
        iter->cur_seq = r.info->seq + 1;
        ret = true;
 out:
+       printk_safe_exit_irqrestore(flags);
        if (len)
                *len = l;
        return ret;
 }
-
-/**
- * kmsg_dump_get_line - retrieve one kmsg log line
- * @iter: kmsg dump iterator
- * @syslog: include the "<4>" prefixes
- * @line: buffer to copy the line to
- * @size: maximum size of the buffer
- * @len: length of line placed into buffer
- *
- * Start at the beginning of the kmsg buffer, with the oldest kmsg
- * record, and copy one record into the provided buffer.
- *
- * Consecutive calls will return the next available record moving
- * towards the end of the buffer with the youngest messages.
- *
- * A return value of FALSE indicates that there are no more records to
- * read.
- */
-bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog,
-                       char *line, size_t size, size_t *len)
-{
-       unsigned long flags;
-       bool ret;
-
-       printk_safe_enter_irqsave(flags);
-       ret = kmsg_dump_get_line_nolock(iter, syslog, line, size, len);
-       printk_safe_exit_irqrestore(flags);
-
-       return ret;
-}
 EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
 
 /**
@@ -3550,22 +3521,6 @@ out:
 }
 EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
 
-/**
- * kmsg_dump_rewind_nolock - reset the iterator (unlocked version)
- * @iter: kmsg dump iterator
- *
- * Reset the dumper's iterator so that kmsg_dump_get_line() and
- * kmsg_dump_get_buffer() can be called again and used multiple
- * times within the same dumper.dump() callback.
- *
- * The function is similar to kmsg_dump_rewind(), but grabs no locks.
- */
-void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter)
-{
-       iter->cur_seq = latched_seq_read_nolock(&clear_seq);
-       iter->next_seq = prb_next_seq(prb);
-}
-
 /**
  * kmsg_dump_rewind - reset the iterator
  * @iter: kmsg dump iterator
@@ -3579,7 +3534,8 @@ void kmsg_dump_rewind(struct kmsg_dump_iter *iter)
        unsigned long flags;
 
        printk_safe_enter_irqsave(flags);
-       kmsg_dump_rewind_nolock(iter);
+       iter->cur_seq = latched_seq_read_nolock(&clear_seq);
+       iter->next_seq = prb_next_seq(prb);
        printk_safe_exit_irqrestore(flags);
 }
 EXPORT_SYMBOL_GPL(kmsg_dump_rewind);