From e831e400f73b0e7aa4629200c2ef71e068262414 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Wed, 3 Mar 2021 11:15:17 +0100 Subject: printk: kmsg_dump: remove unused fields struct kmsg_dumper still contains some fields that were used to iterate the old ringbuffer. They are no longer used. Remove them and update the struct documentation. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-5-john.ogness@linutronix.de --- include/linux/kmsg_dump.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 3378bcbe585e..ae38035f1dca 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -36,6 +36,9 @@ 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 */ struct kmsg_dumper { struct list_head list; @@ -45,8 +48,6 @@ struct kmsg_dumper { bool registered; /* private state of the kmsg iterator */ - u32 cur_idx; - u32 next_idx; u64 cur_seq; u64 next_seq; }; -- cgit v1.2.3 From 726b5097701a8d46f5354be780e1a11fc4ca1187 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Wed, 3 Mar 2021 11:15:18 +0100 Subject: printk: refactor kmsg_dump_get_buffer() kmsg_dump_get_buffer() requires nearly the same logic as syslog_print_all(), but uses different variable names and does not make use of the ringbuffer loop macros. Modify kmsg_dump_get_buffer() so that the implementation is as similar to syslog_print_all() as possible. A follow-up commit will move this common logic into a separate helper function. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-6-john.ogness@linutronix.de --- include/linux/kmsg_dump.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index ae38035f1dca..070c994ff19f 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -62,7 +62,7 @@ bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, char *line, size_t size, size_t *len); bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, - char *buf, size_t size, size_t *len); + char *buf, size_t size, size_t *len_out); void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper); -- cgit v1.2.3 From 5f6c7648e556f41a3064bb6dceb9e102c50b618d Mon Sep 17 00:00:00 2001 From: John Ogness Date: Wed, 3 Mar 2021 11:15:24 +0100 Subject: printk: kmsg_dumper: remove @active field 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 Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-12-john.ogness@linutronix.de --- include/linux/kmsg_dump.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux') 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 */ -- cgit v1.2.3 From f9f3f02db98bbe678a8e57fe9432b196174744a3 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Wed, 3 Mar 2021 11:15:25 +0100 Subject: printk: introduce a kmsg_dump iterator Rather than storing the iterator information in the registered kmsg_dumper structure, create a separate iterator structure. The kmsg_dump_iter structure can reside on the stack of the caller, thus allowing lockless use of the kmsg_dump functions. Update code that accesses the kernel logs using the kmsg_dumper structure to use the new kmsg_dump_iter structure. For kmsg_dumpers, this also means adding a call to kmsg_dump_rewind() to initialize the iterator. All this is in preparation for removal of @logbuf_lock. Signed-off-by: John Ogness Reviewed-by: Kees Cook # pstore Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-13-john.ogness@linutronix.de --- include/linux/kmsg_dump.h | 36 ++++++++++++++++++++---------------- 1 file changed, 20 insertions(+), 16 deletions(-) (limited to 'include/linux') diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 84eaa2090efa..36c8c57e1051 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -29,6 +29,16 @@ enum kmsg_dump_reason { KMSG_DUMP_MAX }; +/** + * struct kmsg_dump_iter - iterator for retrieving kernel messages + * @cur_seq: Points to the oldest message to dump + * @next_seq: Points after the newest message to dump + */ +struct kmsg_dump_iter { + u64 cur_seq; + u64 next_seq; +}; + /** * struct kmsg_dumper - kernel crash message dumper structure * @list: Entry in the dumper list (private) @@ -36,35 +46,29 @@ 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 - * @cur_seq: Points to the oldest message to dump - * @next_seq: Points after the newest message to dump */ 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 registered; - - /* private state of the kmsg iterator */ - u64 cur_seq; - u64 next_seq; }; #ifdef CONFIG_PRINTK void kmsg_dump(enum kmsg_dump_reason reason); -bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, +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_dumper *dumper, bool syslog, +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_dumper *dumper, bool syslog, +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_dumper *dumper); +void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter); -void kmsg_dump_rewind(struct kmsg_dumper *dumper); +void kmsg_dump_rewind(struct kmsg_dump_iter *iter); int kmsg_dump_register(struct kmsg_dumper *dumper); @@ -76,30 +80,30 @@ static inline void kmsg_dump(enum kmsg_dump_reason reason) { } -static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, +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_dumper *dumper, bool syslog, +static inline bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, const char *line, size_t size, size_t *len) { return false; } -static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, +static inline bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, char *buf, size_t size, size_t *len) { return false; } -static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) +static inline void kmsg_dump_rewind_nolock(struct kmsg_dump_iter *iter) { } -static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper) +static inline void kmsg_dump_rewind(struct kmsg_dump_iter *iter) { } -- cgit v1.2.3 From a4f987653241db9fa1f99531b430cebb83f1eae1 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Wed, 3 Mar 2021 11:15:27 +0100 Subject: 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 Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-15-john.ogness@linutronix.de --- include/linux/kmsg_dump.h | 16 ---------------- 1 file changed, 16 deletions(-) (limited to 'include/linux') diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 36c8c57e1051..906521c2329c 100644 --- 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) { } -- cgit v1.2.3