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printk: inline log_output(),log_store() in vprintk_store() 

In preparation for removing logbuf_lock, inline log_output()
and log_store() into vprintk_store(). This will simplify dealing
with the various code branches and fallbacks that are possible.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20201209004453.17720-2-john.ogness@linutronix.de
This commit is contained in:
John Ogness 2020-12-09 01:50:52 +01:06 committed by Petr Mladek
parent 43d6ecd97c
commit 6b916706f8
1 changed files with 67 additions and 78 deletions
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145
kernel/printk/printk.c
View File

@ -491,52 +491,6 @@ static void truncate_msg(u16 *text_len, u16 *trunc_msg_len)
*trunc_msg_len = 0;
}
/* insert record into the buffer, discard old ones, update heads */
static int log_store(u32 caller_id, int facility, int level,
enum log_flags flags, u64 ts_nsec,
const struct dev_printk_info *dev_info,
const char *text, u16 text_len)
{
struct prb_reserved_entry e;
struct printk_record r;
u16 trunc_msg_len = 0;
prb_rec_init_wr(&r, text_len);
if (!prb_reserve(&e, prb, &r)) {
/* truncate the message if it is too long for empty buffer */
truncate_msg(&text_len, &trunc_msg_len);
prb_rec_init_wr(&r, text_len + trunc_msg_len);
/* survive when the log buffer is too small for trunc_msg */
if (!prb_reserve(&e, prb, &r))
return 0;
}
/* fill message */
memcpy(&r.text_buf[0], text, text_len);
if (trunc_msg_len)
memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
r.info->text_len = text_len + trunc_msg_len;
r.info->facility = facility;
r.info->level = level & 7;
r.info->flags = flags & 0x1f;
if (ts_nsec > 0)
r.info->ts_nsec = ts_nsec;
else
r.info->ts_nsec = local_clock();
r.info->caller_id = caller_id;
if (dev_info)
memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));
/* A message without a trailing newline can be continued. */
if (!(flags & LOG_NEWLINE))
prb_commit(&e);
else
prb_final_commit(&e);
return (text_len + trunc_msg_len);
}
int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);
static int syslog_action_restricted(int type)
@ -1907,44 +1861,28 @@ static inline u32 printk_caller_id(void)
0x80000000 + raw_smp_processor_id();
}
static size_t log_output(int facility, int level, enum log_flags lflags,
const struct dev_printk_info *dev_info,
char *text, size_t text_len)
{
const u32 caller_id = printk_caller_id();
if (lflags & LOG_CONT) {
struct prb_reserved_entry e;
struct printk_record r;
prb_rec_init_wr(&r, text_len);
if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
memcpy(&r.text_buf[r.info->text_len], text, text_len);
r.info->text_len += text_len;
if (lflags & LOG_NEWLINE) {
r.info->flags |= LOG_NEWLINE;
prb_final_commit(&e);
} else {
prb_commit(&e);
}
return text_len;
}
}
/* Store it in the record log */
return log_store(caller_id, facility, level, lflags, 0,
dev_info, text, text_len);
}
/* Must be called under logbuf_lock. */
int vprintk_store(int facility, int level,
const struct dev_printk_info *dev_info,
const char *fmt, va_list args)
{
const u32 caller_id = printk_caller_id();
static char textbuf[LOG_LINE_MAX];
char *text = textbuf;
size_t text_len;
struct prb_reserved_entry e;
enum log_flags lflags = 0;
struct printk_record r;
u16 trunc_msg_len = 0;
char *text = textbuf;
u16 text_len;
u64 ts_nsec;
/*
* Since the duration of printk() can vary depending on the message
* and state of the ringbuffer, grab the timestamp now so that it is
* close to the call of printk(). This provides a more deterministic
* timestamp with respect to the caller.
*/
ts_nsec = local_clock();
/*
* The printf needs to come first; we need the syslog
@ -1983,7 +1921,58 @@ int vprintk_store(int facility, int level,
if (dev_info)
lflags |= LOG_NEWLINE;
return log_output(facility, level, lflags, dev_info, text, text_len);
if (lflags & LOG_CONT) {
prb_rec_init_wr(&r, text_len);
if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
memcpy(&r.text_buf[r.info->text_len], text, text_len);
r.info->text_len += text_len;
if (lflags & LOG_NEWLINE) {
r.info->flags |= LOG_NEWLINE;
prb_final_commit(&e);
} else {
prb_commit(&e);
}
return text_len;
}
}
/*
* Explicitly initialize the record before every prb_reserve() call.
* prb_reserve_in_last() and prb_reserve() purposely invalidate the
* structure when they fail.
*/
prb_rec_init_wr(&r, text_len);
if (!prb_reserve(&e, prb, &r)) {
/* truncate the message if it is too long for empty buffer */
truncate_msg(&text_len, &trunc_msg_len);
prb_rec_init_wr(&r, text_len + trunc_msg_len);
if (!prb_reserve(&e, prb, &r))
return 0;
}
/* fill message */
memcpy(&r.text_buf[0], text, text_len);
if (trunc_msg_len)
memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
r.info->text_len = text_len + trunc_msg_len;
r.info->facility = facility;
r.info->level = level & 7;
r.info->flags = lflags & 0x1f;
r.info->ts_nsec = ts_nsec;
r.info->caller_id = caller_id;
if (dev_info)
memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));
/* A message without a trailing newline can be continued. */
if (!(lflags & LOG_NEWLINE))
prb_commit(&e);
else
prb_final_commit(&e);
return (text_len + trunc_msg_len);
}
asmlinkage int vprintk_emit(int facility, int level,