From 7c35d5807ad1cb9afbbd73a093ed3b4ed447cd9c Mon Sep 17 00:00:00 2001 From: John Ogness Date: Mon, 21 Dec 2020 10:27:58 +0106 Subject: [PATCH 093/323] printk: kmsg_dump: remove _nolock() variants Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.215-rt107.tar.xz 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 --- arch/powerpc/xmon/xmon.c | 4 +-- include/linux/kmsg_dump.h | 18 +---------- kernel/debug/kdb/kdb_main.c | 8 ++--- kernel/printk/printk.c | 60 +++++-------------------------------- 4 files changed, 15 insertions(+), 75 deletions(-) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 9f62cca6c5948..2eef587bf51d5 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -3015,9 +3015,9 @@ 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 2fdb10ab17994..86673930c8ea2 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -60,18 +60,13 @@ struct kmsg_dumper { #ifdef CONFIG_PRINTK void kmsg_dump(enum kmsg_dump_reason reason); -bool kmsg_dump_get_line_nolock(struct kmsg_dumper_iter *iter, bool syslog, - char *line, size_t size, size_t *len); - bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog, char *line, size_t size, size_t *len); bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog, char *buf, size_t size, size_t *len_out); -void kmsg_dump_rewind_nolock(struct kmsg_dumper_iter *iter); - -void kmsg_dump_rewind(struct kmsg_dumper_iter *dumper_iter); +void kmsg_dump_rewind(struct kmsg_dumper_iter *iter); int kmsg_dump_register(struct kmsg_dumper *dumper); @@ -83,13 +78,6 @@ static inline void kmsg_dump(enum kmsg_dump_reason reason) { } -static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper_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_iter *iter, bool syslog, const char *line, size_t size, size_t *len) { @@ -102,10 +90,6 @@ static inline bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool sysl return false; } -static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper_iter *iter) -{ -} - static inline void kmsg_dump_rewind(struct kmsg_dumper_iter *iter) { } diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index aa424a1d65d01..b97d05072ca4b 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2180,8 +2180,8 @@ 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) { @@ -2213,8 +2213,8 @@ 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 9fde03f1e29bf..e18f1f09ab727 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3416,7 +3416,7 @@ 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 dumper iterator * @syslog: include the "<4>" prefixes * @line: buffer to copy the line to @@ -3431,18 +3431,18 @@ 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_dumper_iter *iter, bool syslog, - char *line, size_t size, size_t *len) +bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog, + char *line, size_t size, size_t *len) { struct printk_info info; unsigned int line_count; struct printk_record r; + unsigned long flags; size_t l = 0; bool ret = false; + printk_safe_enter_irqsave(flags); prb_rec_init_rd(&r, &info, line, size); if (!iter->active) @@ -3466,40 +3466,11 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper_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 dumper 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_dumper_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); /** @@ -3588,22 +3559,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog, } EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); -/** - * kmsg_dump_rewind_nolock - reset the iterator (unlocked version) - * @iter: kmsg dumper 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_dumper_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 dumper iterator @@ -3617,7 +3572,8 @@ void kmsg_dump_rewind(struct kmsg_dumper_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); -- 2.44.0