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Subject[PATCH V2 23/23] printk: Move kmsg_dump functions to separate file
Date
Generic restructuring.

Create kmsg_dump.c, add to Makefile and remove from printk.c

Signed-off-by: Joe Perches <joe@perches.com>
---
kernel/printk/Makefile | 1 +
kernel/printk/kmsg_dump.c | 328 +++++++++++++++++++++++++++++++++++++++++++++
kernel/printk/printk.c | 318 -------------------------------------------
3 files changed, 329 insertions(+), 318 deletions(-)
create mode 100644 kernel/printk/kmsg_dump.c

diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 7947661..b0072b0 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -2,4 +2,5 @@ obj-y = printk.o
obj-y += printk_log.o
obj-y += devkmsg.o
obj-y += printk_syslog.o
+obj-y += kmsg_dump.o
obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o
diff --git a/kernel/printk/kmsg_dump.c b/kernel/printk/kmsg_dump.c
new file mode 100644
index 0000000..7962172
--- /dev/null
+++ b/kernel/printk/kmsg_dump.c
@@ -0,0 +1,328 @@
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/kexec.h>
+#include <linux/moduleparam.h>
+#include <linux/export.h>
+#include <linux/kmsg_dump.h>
+#include <linux/rculist.h>
+#include <linux/stat.h>
+
+#include "printk_log.h"
+
+static DEFINE_SPINLOCK(dump_list_lock);
+static LIST_HEAD(dump_list);
+
+/**
+ * kmsg_dump_register - register a kernel log dumper.
+ * @dumper: pointer to the kmsg_dumper structure
+ *
+ * Adds a kernel log dumper to the system. The dump callback in the
+ * structure will be called when the kernel oopses or panics and must be
+ * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
+ */
+int kmsg_dump_register(struct kmsg_dumper *dumper)
+{
+ unsigned long flags;
+ int err = -EBUSY;
+
+ /* The dump callback needs to be set */
+ if (!dumper->dump)
+ return -EINVAL;
+
+ spin_lock_irqsave(&dump_list_lock, flags);
+ /* Don't allow registering multiple times */
+ if (!dumper->registered) {
+ dumper->registered = 1;
+ list_add_tail_rcu(&dumper->list, &dump_list);
+ err = 0;
+ }
+ spin_unlock_irqrestore(&dump_list_lock, flags);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_register);
+
+/**
+ * kmsg_dump_unregister - unregister a kmsg dumper.
+ * @dumper: pointer to the kmsg_dumper structure
+ *
+ * Removes a dump device from the system. Returns zero on success and
+ * %-EINVAL otherwise.
+ */
+int kmsg_dump_unregister(struct kmsg_dumper *dumper)
+{
+ unsigned long flags;
+ int err = -EINVAL;
+
+ spin_lock_irqsave(&dump_list_lock, flags);
+ if (dumper->registered) {
+ dumper->registered = 0;
+ list_del_rcu(&dumper->list);
+ err = 0;
+ }
+ spin_unlock_irqrestore(&dump_list_lock, flags);
+ synchronize_rcu();
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
+
+static bool always_kmsg_dump;
+module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
+
+/**
+ * kmsg_dump - dump kernel log to kernel message dumpers.
+ * @reason: the reason (oops, panic etc) for dumping
+ *
+ * Call each of the registered dumper's dump() callback, which can
+ * retrieve the kmsg records with kmsg_dump_get_line() or
+ * kmsg_dump_get_buffer().
+ */
+void kmsg_dump(enum kmsg_dump_reason reason)
+{
+ struct kmsg_dumper *dumper;
+ unsigned long flags;
+
+ if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
+ return;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(dumper, &dump_list, list) {
+ if (dumper->max_reason && reason > dumper->max_reason)
+ continue;
+
+ /* initialize iterator with data about the stored records */
+ dumper->active = true;
+
+ raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
+ dumper->cur_seq = printk_log_clear_seq;
+ dumper->cur_idx = printk_log_clear_idx;
+ dumper->next_seq = printk_log_next_seq;
+ dumper->next_idx = printk_log_next_idx;
+ raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+
+ /* invoke dumper which will iterate over records */
+ dumper->dump(dumper, reason);
+
+ /* reset iterator */
+ dumper->active = false;
+ }
+ rcu_read_unlock();
+}
+
+/**
+ * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
+ * @dumper: registered kmsg dumper
+ * @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.
+ *
+ * The function is similar to kmsg_dump_get_line(), but grabs no locks.
+ */
+bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
+ char *line, size_t size, size_t *len)
+{
+ struct printk_log *msg;
+ size_t l = 0;
+ bool ret = false;
+
+ if (!dumper->active)
+ goto out;
+
+ if (dumper->cur_seq < printk_log_first_seq) {
+ /* messages are gone, move to first available one */
+ dumper->cur_seq = printk_log_first_seq;
+ dumper->cur_idx = printk_log_first_idx;
+ }
+
+ /* last entry */
+ if (dumper->cur_seq >= printk_log_next_seq)
+ goto out;
+
+ msg = printk_log_from_idx(dumper->cur_idx);
+ l = printk_msg_print_text(msg, 0, syslog, line, size);
+
+ dumper->cur_idx = printk_log_next(dumper->cur_idx);
+ dumper->cur_seq++;
+ ret = true;
+out:
+ if (len)
+ *len = l;
+ return ret;
+}
+
+/**
+ * kmsg_dump_get_line - retrieve one kmsg log line
+ * @dumper: registered kmsg dumper
+ * @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_dumper *dumper, bool syslog,
+ char *line, size_t size, size_t *len)
+{
+ unsigned long flags;
+ bool ret;
+
+ raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
+ ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
+ raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+
+/**
+ * kmsg_dump_get_buffer - copy kmsg log lines
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @buf: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the end of the kmsg buffer and fill the provided buffer
+ * with as many of the the *youngest* kmsg records that fit into it.
+ * If the buffer is large enough, all available kmsg records will be
+ * copied with a single call.
+ *
+ * Consecutive calls will fill the buffer with the next block of
+ * available older records, not including the earlier retrieved ones.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ char *buf, size_t size, size_t *len)
+{
+ unsigned long flags;
+ u64 seq;
+ u32 idx;
+ u64 next_seq;
+ u32 next_idx;
+ enum printk_log_flags prev;
+ size_t l = 0;
+ bool ret = false;
+
+ if (!dumper->active)
+ goto out;
+
+ raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
+ if (dumper->cur_seq < printk_log_first_seq) {
+ /* messages are gone, move to first available one */
+ dumper->cur_seq = printk_log_first_seq;
+ dumper->cur_idx = printk_log_first_idx;
+ }
+
+ /* last entry */
+ if (dumper->cur_seq >= dumper->next_seq) {
+ raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+ goto out;
+ }
+
+ /* calculate length of entire buffer */
+ seq = dumper->cur_seq;
+ idx = dumper->cur_idx;
+ prev = 0;
+ while (seq < dumper->next_seq) {
+ struct printk_log *msg = printk_log_from_idx(idx);
+
+ l += printk_msg_print_text(msg, prev, true, NULL, 0);
+ idx = printk_log_next(idx);
+ seq++;
+ prev = msg->flags;
+ }
+
+ /* move first record forward until length fits into the buffer */
+ seq = dumper->cur_seq;
+ idx = dumper->cur_idx;
+ prev = 0;
+ while (l > size && seq < dumper->next_seq) {
+ struct printk_log *msg = printk_log_from_idx(idx);
+
+ l -= printk_msg_print_text(msg, prev, true, NULL, 0);
+ idx = printk_log_next(idx);
+ seq++;
+ prev = msg->flags;
+ }
+
+ /* last message in next interation */
+ next_seq = seq;
+ next_idx = idx;
+
+ l = 0;
+ prev = 0;
+ while (seq < dumper->next_seq) {
+ struct printk_log *msg = printk_log_from_idx(idx);
+
+ l += printk_msg_print_text(msg, prev, syslog, buf + l, size - l);
+ idx = printk_log_next(idx);
+ seq++;
+ prev = msg->flags;
+ }
+
+ dumper->next_seq = next_seq;
+ dumper->next_idx = next_idx;
+ ret = true;
+ raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+out:
+ if (len)
+ *len = l;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+
+/**
+ * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
+ * @dumper: registered kmsg dumper
+ *
+ * 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_dumper *dumper)
+{
+ dumper->cur_seq = printk_log_clear_seq;
+ dumper->cur_idx = printk_log_clear_idx;
+ dumper->next_seq = printk_log_next_seq;
+ dumper->next_idx = printk_log_next_idx;
+}
+
+/**
+ * kmsg_dump_rewind - reset the interator
+ * @dumper: registered kmsg dumper
+ *
+ * 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.
+ */
+void kmsg_dump_rewind(struct kmsg_dumper *dumper)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
+ kmsg_dump_rewind_nolock(dumper);
+ raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index bed0e7d..9b31ded 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -33,7 +33,6 @@
#include <linux/kexec.h>
#include <linux/kdb.h>
#include <linux/ratelimit.h>
-#include <linux/kmsg_dump.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/rculist.h>
@@ -1511,321 +1510,4 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies,
}
EXPORT_SYMBOL(printk_timed_ratelimit);

-static DEFINE_SPINLOCK(dump_list_lock);
-static LIST_HEAD(dump_list);
-
-/**
- * kmsg_dump_register - register a kernel log dumper.
- * @dumper: pointer to the kmsg_dumper structure
- *
- * Adds a kernel log dumper to the system. The dump callback in the
- * structure will be called when the kernel oopses or panics and must be
- * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
- */
-int kmsg_dump_register(struct kmsg_dumper *dumper)
-{
- unsigned long flags;
- int err = -EBUSY;
-
- /* The dump callback needs to be set */
- if (!dumper->dump)
- return -EINVAL;
-
- spin_lock_irqsave(&dump_list_lock, flags);
- /* Don't allow registering multiple times */
- if (!dumper->registered) {
- dumper->registered = 1;
- list_add_tail_rcu(&dumper->list, &dump_list);
- err = 0;
- }
- spin_unlock_irqrestore(&dump_list_lock, flags);
-
- return err;
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_register);
-
-/**
- * kmsg_dump_unregister - unregister a kmsg dumper.
- * @dumper: pointer to the kmsg_dumper structure
- *
- * Removes a dump device from the system. Returns zero on success and
- * %-EINVAL otherwise.
- */
-int kmsg_dump_unregister(struct kmsg_dumper *dumper)
-{
- unsigned long flags;
- int err = -EINVAL;
-
- spin_lock_irqsave(&dump_list_lock, flags);
- if (dumper->registered) {
- dumper->registered = 0;
- list_del_rcu(&dumper->list);
- err = 0;
- }
- spin_unlock_irqrestore(&dump_list_lock, flags);
- synchronize_rcu();
-
- return err;
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
-
-static bool always_kmsg_dump;
-module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
-
-/**
- * kmsg_dump - dump kernel log to kernel message dumpers.
- * @reason: the reason (oops, panic etc) for dumping
- *
- * Call each of the registered dumper's dump() callback, which can
- * retrieve the kmsg records with kmsg_dump_get_line() or
- * kmsg_dump_get_buffer().
- */
-void kmsg_dump(enum kmsg_dump_reason reason)
-{
- struct kmsg_dumper *dumper;
- unsigned long flags;
-
- if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
- return;
-
- rcu_read_lock();
- list_for_each_entry_rcu(dumper, &dump_list, list) {
- if (dumper->max_reason && reason > dumper->max_reason)
- continue;
-
- /* initialize iterator with data about the stored records */
- dumper->active = true;
-
- raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
- dumper->cur_seq = printk_log_clear_seq;
- dumper->cur_idx = printk_log_clear_idx;
- dumper->next_seq = printk_log_next_seq;
- dumper->next_idx = printk_log_next_idx;
- raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-
- /* invoke dumper which will iterate over records */
- dumper->dump(dumper, reason);
-
- /* reset iterator */
- dumper->active = false;
- }
- rcu_read_unlock();
-}
-
-/**
- * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
- * @dumper: registered kmsg dumper
- * @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.
- *
- * The function is similar to kmsg_dump_get_line(), but grabs no locks.
- */
-bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
- char *line, size_t size, size_t *len)
-{
- struct printk_log *msg;
- size_t l = 0;
- bool ret = false;
-
- if (!dumper->active)
- goto out;
-
- if (dumper->cur_seq < printk_log_first_seq) {
- /* messages are gone, move to first available one */
- dumper->cur_seq = printk_log_first_seq;
- dumper->cur_idx = printk_log_first_idx;
- }
-
- /* last entry */
- if (dumper->cur_seq >= printk_log_next_seq)
- goto out;
-
- msg = printk_log_from_idx(dumper->cur_idx);
- l = printk_msg_print_text(msg, 0, syslog, line, size);
-
- dumper->cur_idx = printk_log_next(dumper->cur_idx);
- dumper->cur_seq++;
- ret = true;
-out:
- if (len)
- *len = l;
- return ret;
-}
-
-/**
- * kmsg_dump_get_line - retrieve one kmsg log line
- * @dumper: registered kmsg dumper
- * @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_dumper *dumper, bool syslog,
- char *line, size_t size, size_t *len)
-{
- unsigned long flags;
- bool ret;
-
- raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
- ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
- raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
-
-/**
- * kmsg_dump_get_buffer - copy kmsg log lines
- * @dumper: registered kmsg dumper
- * @syslog: include the "<4>" prefixes
- * @buf: buffer to copy the line to
- * @size: maximum size of the buffer
- * @len: length of line placed into buffer
- *
- * Start at the end of the kmsg buffer and fill the provided buffer
- * with as many of the the *youngest* kmsg records that fit into it.
- * If the buffer is large enough, all available kmsg records will be
- * copied with a single call.
- *
- * Consecutive calls will fill the buffer with the next block of
- * available older records, not including the earlier retrieved ones.
- *
- * A return value of FALSE indicates that there are no more records to
- * read.
- */
-bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
- char *buf, size_t size, size_t *len)
-{
- unsigned long flags;
- u64 seq;
- u32 idx;
- u64 next_seq;
- u32 next_idx;
- enum printk_log_flags prev;
- size_t l = 0;
- bool ret = false;
-
- if (!dumper->active)
- goto out;
-
- raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
- if (dumper->cur_seq < printk_log_first_seq) {
- /* messages are gone, move to first available one */
- dumper->cur_seq = printk_log_first_seq;
- dumper->cur_idx = printk_log_first_idx;
- }
-
- /* last entry */
- if (dumper->cur_seq >= dumper->next_seq) {
- raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
- goto out;
- }
-
- /* calculate length of entire buffer */
- seq = dumper->cur_seq;
- idx = dumper->cur_idx;
- prev = 0;
- while (seq < dumper->next_seq) {
- struct printk_log *msg = printk_log_from_idx(idx);
-
- l += printk_msg_print_text(msg, prev, true, NULL, 0);
- idx = printk_log_next(idx);
- seq++;
- prev = msg->flags;
- }
-
- /* move first record forward until length fits into the buffer */
- seq = dumper->cur_seq;
- idx = dumper->cur_idx;
- prev = 0;
- while (l > size && seq < dumper->next_seq) {
- struct printk_log *msg = printk_log_from_idx(idx);
-
- l -= printk_msg_print_text(msg, prev, true, NULL, 0);
- idx = printk_log_next(idx);
- seq++;
- prev = msg->flags;
- }
-
- /* last message in next interation */
- next_seq = seq;
- next_idx = idx;
-
- l = 0;
- prev = 0;
- while (seq < dumper->next_seq) {
- struct printk_log *msg = printk_log_from_idx(idx);
-
- l += printk_msg_print_text(msg, prev, syslog, buf + l, size - l);
- idx = printk_log_next(idx);
- seq++;
- prev = msg->flags;
- }
-
- dumper->next_seq = next_seq;
- dumper->next_idx = next_idx;
- ret = true;
- raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-out:
- if (len)
- *len = l;
- return ret;
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
-
-/**
- * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
- * @dumper: registered kmsg dumper
- *
- * 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_dumper *dumper)
-{
- dumper->cur_seq = printk_log_clear_seq;
- dumper->cur_idx = printk_log_clear_idx;
- dumper->next_seq = printk_log_next_seq;
- dumper->next_idx = printk_log_next_idx;
-}
-
-/**
- * kmsg_dump_rewind - reset the interator
- * @dumper: registered kmsg dumper
- *
- * 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.
- */
-void kmsg_dump_rewind(struct kmsg_dumper *dumper)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
- kmsg_dump_rewind_nolock(dumper);
- raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
#endif
--
1.7.8.112.g3fd21


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