[PATCH v4 22/34] vsprintf: Refactor hex_string, bitmap_string_list, bitmap_string

From: Kent Overstreet
Date: Sun Jun 19 2022 - 20:44:45 EST


This patch cleans up printf_spec handling: these functions only use
spec.field_width and they do not interpret it in the normal way -
instead it's a number of bits/bytes passed in to print, so these
functions are changed to take that parameter directly.

Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
---
lib/vsprintf.c | 60 +++++++++++++++++++++++---------------------------
1 file changed, 28 insertions(+), 32 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 7f47533ed8..fcdf187b21 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -53,6 +53,7 @@
#include <asm/unaligned.h>

#include <linux/string_helpers.h>
+#include <linux/pretty-printers.h>
#include "kstrtox.h"

/* Disable pointer hashing if requested */
@@ -1151,18 +1152,23 @@ void resource_string(struct printbuf *out, struct resource *res,
}

static noinline_for_stack
-void hex_string(struct printbuf *out, u8 *addr,
- struct printf_spec spec, const char *fmt)
+void hex_string(struct printbuf *out, const u8 *addr,
+ int len, const char *fmt)
{
- int i, len = 1; /* if we pass '%ph[CDN]', field width remains
- negative value, fallback to the default */
char separator;

- if (spec.field_width == 0)
- /* nothing to print */
+ /* nothing to print */
+ if (len == 0)
return;

- if (check_pointer_spec(out, addr, spec))
+ /* if we pass '%ph[CDN]', field width remains
+ negative value, fallback to the default */
+ if (len < 0)
+ len = 1;
+
+ len = min(len, 64);
+
+ if (check_pointer(out, addr))
return;

switch (fmt[1]) {
@@ -1180,34 +1186,21 @@ void hex_string(struct printbuf *out, u8 *addr,
break;
}

- if (spec.field_width > 0)
- len = min_t(int, spec.field_width, 64);
-
- for (i = 0; i < len; ++i) {
- __prt_char(out, hex_asc_hi(addr[i]));
- __prt_char(out, hex_asc_lo(addr[i]));
-
- if (separator && i != len - 1)
- __prt_char(out, separator);
- }
-
- printbuf_nul_terminate(out);
+ prt_hex_bytes(out, addr, len, 1, separator);
}

static noinline_for_stack
-void bitmap_string(struct printbuf *out, unsigned long *bitmap,
- struct printf_spec spec, const char *fmt)
+void bitmap_string(struct printbuf *out, unsigned long *bitmap, int nr_bits)
{
+ struct printf_spec spec = { .flags = SMALL | ZEROPAD, .base = 16 };
const int CHUNKSZ = 32;
- int nr_bits = max_t(int, spec.field_width, 0);
int i, chunksz;
bool first = true;

- if (check_pointer_spec(out, bitmap, spec))
- return;
+ nr_bits = max(nr_bits, 0);

- /* reused to print numbers */
- spec = (struct printf_spec){ .flags = SMALL | ZEROPAD, .base = 16 };
+ if (check_pointer(out, bitmap))
+ return;

chunksz = nr_bits & (CHUNKSZ - 1);
if (chunksz == 0)
@@ -1236,13 +1229,14 @@ void bitmap_string(struct printbuf *out, unsigned long *bitmap,

static noinline_for_stack
void bitmap_list_string(struct printbuf *out, unsigned long *bitmap,
- struct printf_spec spec, const char *fmt)
+ int nr_bits)
{
- int nr_bits = max_t(int, spec.field_width, 0);
bool first = true;
int rbot, rtop;

- if (check_pointer_spec(out, bitmap, spec))
+ nr_bits = max(nr_bits, 0);
+
+ if (check_pointer(out, bitmap))
return ;

for_each_set_bitrange(rbot, rtop, bitmap, nr_bits) {
@@ -2257,13 +2251,15 @@ void pointer(struct printbuf *out, const char *fmt,
resource_string(out, ptr, fmt[0] == 'R');
return do_width_precision(out, prev_pos, spec);
case 'h':
- return hex_string(out, ptr, spec, fmt);
+ /* Uses field_width but _not_ as field size */
+ return hex_string(out, ptr, spec.field_width, fmt);
case 'b':
+ /* Uses field_width but _not_ as field size */
switch (fmt[1]) {
case 'l':
- return bitmap_list_string(out, ptr, spec, fmt);
+ return bitmap_list_string(out, ptr, spec.field_width);
default:
- return bitmap_string(out, ptr, spec, fmt);
+ return bitmap_string(out, ptr, spec.field_width);
}
case 'M': /* Colon separated: 00:01:02:03:04:05 */
case 'm': /* Contiguous: 000102030405 */
--
2.36.1