diff options
Diffstat (limited to 'kernel/printk.c')
| -rw-r--r-- | kernel/printk.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/kernel/printk.c b/kernel/printk.c index f02f1f5ddc30..50c33411442d 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -217,6 +217,7 @@ static DEFINE_RAW_SPINLOCK(logbuf_lock); /* the next printk record to read by syslog(READ) or /proc/kmsg */ static u64 syslog_seq; static u32 syslog_idx; +static size_t syslog_partial; /* index and sequence number of the first record stored in the buffer */ static u64 log_first_seq; @@ -890,22 +891,33 @@ static int syslog_print(char __user *buf, int size) while (size > 0) { size_t n; + size_t skip; raw_spin_lock_irq(&logbuf_lock); if (syslog_seq < log_first_seq) { /* messages are gone, move to first one */ syslog_seq = log_first_seq; syslog_idx = log_first_idx; + syslog_partial = 0; } if (syslog_seq == log_next_seq) { raw_spin_unlock_irq(&logbuf_lock); break; } + + skip = syslog_partial; msg = log_from_idx(syslog_idx); n = msg_print_text(msg, true, text, LOG_LINE_MAX); - if (n <= size) { + if (n - syslog_partial <= size) { + /* message fits into buffer, move forward */ syslog_idx = log_next(syslog_idx); syslog_seq++; + n -= syslog_partial; + syslog_partial = 0; + } else if (!len){ + /* partial read(), remember position */ + n = size; + syslog_partial += n; } else n = 0; raw_spin_unlock_irq(&logbuf_lock); @@ -913,17 +925,15 @@ static int syslog_print(char __user *buf, int size) if (!n) break; - len += n; - size -= n; - buf += n; - n = copy_to_user(buf - n, text, n); - - if (n) { - len -= n; + if (copy_to_user(buf, text + skip, n)) { if (!len) len = -EFAULT; break; } + + len += n; + size -= n; + buf += n; } kfree(text); @@ -1107,6 +1117,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) /* messages are gone, move to first one */ syslog_seq = log_first_seq; syslog_idx = log_first_idx; + syslog_partial = 0; } if (from_file) { /* @@ -1129,6 +1140,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) idx = log_next(idx); seq++; } + error -= syslog_partial; } raw_spin_unlock_irq(&logbuf_lock); break; |