tracing: Create seq_buf layer in trace_seq
Create a seq_buf layer that trace_seq sits on. The seq_buf will not
be limited to page size. This will allow other usages of seq_buf
instead of a hard set PAGE_SIZE one that trace_seq has.
Link: http://lkml.kernel.org/r/20141104160221.864997179@goodmis.org
Link: http://lkml.kernel.org/r/20141114011412.170377300@goodmis.org
Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index fabfa0f..8c0c54f 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -27,10 +27,19 @@
#include <linux/trace_seq.h>
/* How much buffer is left on the trace_seq? */
-#define TRACE_SEQ_BUF_LEFT(s) ((PAGE_SIZE - 1) - (s)->len)
+#define TRACE_SEQ_BUF_LEFT(s) seq_buf_buffer_left(&(s)->seq)
/* How much buffer is written? */
-#define TRACE_SEQ_BUF_USED(s) min((s)->len, (unsigned int)(PAGE_SIZE - 1))
+#define TRACE_SEQ_BUF_USED(s) min((s)->seq.len, (unsigned int)(PAGE_SIZE - 1))
+
+/*
+ * trace_seq should work with being initialized with 0s.
+ */
+static inline void __trace_seq_init(struct trace_seq *s)
+{
+ if (unlikely(!s->seq.size))
+ trace_seq_init(s);
+}
/**
* trace_print_seq - move the contents of trace_seq into a seq_file
@@ -43,10 +52,11 @@
*/
int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
- unsigned int len = TRACE_SEQ_BUF_USED(s);
int ret;
- ret = seq_write(m, s->buffer, len);
+ __trace_seq_init(s);
+
+ ret = seq_buf_print_seq(m, &s->seq);
/*
* Only reset this buffer if we successfully wrote to the
@@ -72,24 +82,23 @@
*/
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
+ unsigned int save_len = s->seq.len;
va_list ap;
- int ret;
- if (s->full || !len)
+ if (s->full)
return;
+ __trace_seq_init(s);
+
va_start(ap, fmt);
- ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
+ seq_buf_vprintf(&s->seq, fmt, ap);
va_end(ap);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
- return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);
@@ -104,14 +113,19 @@
void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
- int ret;
+ unsigned int save_len = s->seq.len;
- if (s->full || !len)
+ if (s->full)
return;
- ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
- s->len += ret;
+ __trace_seq_init(s);
+
+ seq_buf_bitmask(&s->seq, maskp, nmaskbits);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ }
}
EXPORT_SYMBOL_GPL(trace_seq_bitmask);
@@ -128,21 +142,20 @@
*/
void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
- int ret;
+ unsigned int save_len = s->seq.len;
- if (s->full || !len)
+ if (s->full)
return;
- ret = vsnprintf(s->buffer + s->len, len, fmt, args);
+ __trace_seq_init(s);
+
+ seq_buf_vprintf(&s->seq, fmt, args);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
- return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_vprintf);
@@ -163,21 +176,21 @@
*/
void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
- unsigned int len = TRACE_SEQ_BUF_LEFT(s);
- int ret;
+ unsigned int save_len = s->seq.len;
- if (s->full || !len)
+ if (s->full)
return;
- ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
+ __trace_seq_init(s);
+
+ seq_buf_bprintf(&s->seq, fmt, binary);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len) {
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
s->full = 1;
return;
}
-
- s->len += ret;
}
EXPORT_SYMBOL_GPL(trace_seq_bprintf);
@@ -198,13 +211,14 @@
if (s->full)
return;
+ __trace_seq_init(s);
+
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
return;
}
- memcpy(s->buffer + s->len, str, len);
- s->len += len;
+ seq_buf_putmem(&s->seq, str, len);
}
EXPORT_SYMBOL_GPL(trace_seq_puts);
@@ -223,12 +237,14 @@
if (s->full)
return;
+ __trace_seq_init(s);
+
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
return;
}
- s->buffer[s->len++] = c;
+ seq_buf_putc(&s->seq, c);
}
EXPORT_SYMBOL_GPL(trace_seq_putc);
@@ -247,19 +263,17 @@
if (s->full)
return;
+ __trace_seq_init(s);
+
if (len > TRACE_SEQ_BUF_LEFT(s)) {
s->full = 1;
return;
}
- memcpy(s->buffer + s->len, mem, len);
- s->len += len;
+ seq_buf_putmem(&s->seq, mem, len);
}
EXPORT_SYMBOL_GPL(trace_seq_putmem);
-#define MAX_MEMHEX_BYTES 8U
-#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
-
/**
* trace_seq_putmem_hex - write raw memory into the buffer in ASCII hex
* @s: trace sequence descriptor
@@ -273,32 +287,26 @@
void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
- unsigned char hex[HEX_CHARS];
- const unsigned char *data = mem;
- unsigned int start_len;
- int i, j;
+ unsigned int save_len = s->seq.len;
if (s->full)
return;
- while (len) {
- start_len = min(len, HEX_CHARS - 1);
-#ifdef __BIG_ENDIAN
- for (i = 0, j = 0; i < start_len; i++) {
-#else
- for (i = start_len-1, j = 0; i >= 0; i--) {
-#endif
- hex[j++] = hex_asc_hi(data[i]);
- hex[j++] = hex_asc_lo(data[i]);
- }
- if (WARN_ON_ONCE(j == 0 || j/2 > len))
- break;
+ __trace_seq_init(s);
- /* j increments twice per loop */
- len -= j / 2;
- hex[j++] = ' ';
+ /* Each byte is represented by two chars */
+ if (len * 2 > TRACE_SEQ_BUF_LEFT(s)) {
+ s->full = 1;
+ return;
+ }
- trace_seq_putmem(s, hex, j);
+ /* The added spaces can still cause an overflow */
+ seq_buf_putmem_hex(&s->seq, mem, len);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return;
}
}
EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
@@ -317,30 +325,28 @@
*/
int trace_seq_path(struct trace_seq *s, const struct path *path)
{
- unsigned char *p;
+ unsigned int save_len = s->seq.len;
+ int ret;
if (s->full)
return 0;
+ __trace_seq_init(s);
+
if (TRACE_SEQ_BUF_LEFT(s) < 1) {
s->full = 1;
return 0;
}
- p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
- if (!IS_ERR(p)) {
- p = mangle_path(s->buffer + s->len, p, "\n");
- if (p) {
- s->len = p - s->buffer;
- return 1;
- }
- } else {
- s->buffer[s->len++] = '?';
- return 1;
+ ret = seq_buf_path(&s->seq, path);
+
+ if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+ s->seq.len = save_len;
+ s->full = 1;
+ return 0;
}
- s->full = 1;
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(trace_seq_path);
@@ -366,25 +372,7 @@
*/
int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt)
{
- int len;
- int ret;
-
- if (!cnt)
- return 0;
-
- if (s->len <= s->readpos)
- return -EBUSY;
-
- len = s->len - s->readpos;
- if (cnt > len)
- cnt = len;
- ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
- if (ret == cnt)
- return -EFAULT;
-
- cnt -= ret;
-
- s->readpos += cnt;
- return cnt;
+ __trace_seq_init(s);
+ return seq_buf_to_user(&s->seq, ubuf, cnt);
}
EXPORT_SYMBOL_GPL(trace_seq_to_user);