diff options
Diffstat (limited to 'features/rt/printk-refactor-kmsg_dump_get_buffer.patch')
| -rw-r--r-- | features/rt/printk-refactor-kmsg_dump_get_buffer.patch | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/features/rt/printk-refactor-kmsg_dump_get_buffer.patch b/features/rt/printk-refactor-kmsg_dump_get_buffer.patch new file mode 100644 index 00000000..3ac51cf4 --- /dev/null +++ b/features/rt/printk-refactor-kmsg_dump_get_buffer.patch @@ -0,0 +1,144 @@ +From d90ed552b2dc6bf64d8c0858f712deb58825fb95 Mon Sep 17 00:00:00 2001 +From: John Ogness <john.ogness@linutronix.de> +Date: Mon, 30 Nov 2020 01:41:56 +0106 +Subject: [PATCH 009/191] 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 <john.ogness@linutronix.de> +Reviewed-by: Petr Mladek <pmladek@suse.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + include/linux/kmsg_dump.h | 2 +- + kernel/printk/printk.c | 60 +++++++++++++++++++++------------------ + 2 files changed, 33 insertions(+), 29 deletions(-) + +diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h +index 235c50982c2d..4095a34db0fa 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); + +diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c +index 77ae2704e979..3f17ff13fd51 100644 +--- a/kernel/printk/printk.c ++++ b/kernel/printk/printk.c +@@ -3424,7 +3424,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line); + * read. + */ + 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) + { + struct printk_info info; + unsigned int line_count; +@@ -3432,12 +3432,10 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, + unsigned long flags; + u64 seq; + u64 next_seq; +- size_t l = 0; ++ size_t len = 0; + bool ret = false; + bool time = printk_time; + +- prb_rec_init_rd(&r, &info, buf, size); +- + if (!dumper->active || !buf || !size) + goto out; + +@@ -3455,48 +3453,54 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, + goto out; + } + +- /* calculate length of entire buffer */ +- seq = dumper->cur_seq; +- while (prb_read_valid_info(prb, seq, &info, &line_count)) { +- if (r.info->seq >= dumper->next_seq) ++ /* ++ * Find first record that fits, including all following records, ++ * into the user-provided buffer for this dump. ++ */ ++ ++ prb_for_each_info(dumper->cur_seq, prb, seq, &info, &line_count) { ++ if (info.seq >= dumper->next_seq) + break; +- l += get_record_print_text_size(&info, line_count, syslog, time); +- seq = r.info->seq + 1; ++ len += get_record_print_text_size(&info, line_count, syslog, time); + } + +- /* move first record forward until length fits into the buffer */ +- seq = dumper->cur_seq; +- while (l >= size && prb_read_valid_info(prb, seq, +- &info, &line_count)) { +- if (r.info->seq >= dumper->next_seq) ++ /* ++ * Move first record forward until length fits into the buffer. Ignore ++ * newest messages that were not counted in the above cycle. Messages ++ * might appear and get lost in the meantime. This is the best effort ++ * that prevents an infinite loop. ++ */ ++ prb_for_each_info(dumper->cur_seq, prb, seq, &info, &line_count) { ++ if (len < size || info.seq >= dumper->next_seq) + break; +- l -= get_record_print_text_size(&info, line_count, syslog, time); +- seq = r.info->seq + 1; ++ len -= get_record_print_text_size(&info, line_count, syslog, time); + } + +- /* last message in next interation */ ++ /* ++ * Next kmsg_dump_get_buffer() invocation will dump block of ++ * older records stored right before this one. ++ */ + next_seq = seq; + +- /* actually read text into the buffer now */ +- l = 0; +- while (prb_read_valid(prb, seq, &r)) { ++ prb_rec_init_rd(&r, &info, buf, size); ++ ++ len = 0; ++ prb_for_each_record(seq, prb, seq, &r) { + if (r.info->seq >= dumper->next_seq) + break; + +- l += record_print_text(&r, syslog, time); +- +- /* adjust record to store to remaining buffer space */ +- prb_rec_init_rd(&r, &info, buf + l, size - l); ++ len += record_print_text(&r, syslog, time); + +- seq = r.info->seq + 1; ++ /* Adjust record to store to remaining buffer space. */ ++ prb_rec_init_rd(&r, &info, buf + len, size - len); + } + + dumper->next_seq = next_seq; + ret = true; + logbuf_unlock_irqrestore(flags); + out: +- if (len) +- *len = l; ++ if (len_out) ++ *len_out = len; + return ret; + } + EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); +-- +2.19.1 + |