lib/vsprintf: add %*pg format specifier
This allow to directly print block_device name.
Currently one should use bdevname() with temporal char buffer.
This is very ineffective because bloat stack usage for deep IO call-traces
Example:
%pg -> sda, sda1 or loop0p1
[AV: fixed a minor braino - position updates should not be dependent
upon having reached the of buffer]
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index b784c270..6389551 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -250,6 +250,12 @@
Passed by reference.
+block_device names:
+
+ %pg sda, sda1 or loop0p1
+
+ For printing name of block_device pointers.
+
struct va_format:
%pV
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index f9cee8e..ac3f947 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -31,6 +31,9 @@
#include <linux/dcache.h>
#include <linux/cred.h>
#include <net/addrconf.h>
+#ifdef CONFIG_BLOCK
+#include <linux/blkdev.h>
+#endif
#include <asm/page.h> /* for PAGE_SIZE */
#include <asm/sections.h> /* for dereference_function_descriptor() */
@@ -613,6 +616,26 @@
return buf;
}
+#ifdef CONFIG_BLOCK
+static noinline_for_stack
+char *bdev_name(char *buf, char *end, struct block_device *bdev,
+ struct printf_spec spec, const char *fmt)
+{
+ struct gendisk *hd = bdev->bd_disk;
+
+ buf = string(buf, end, hd->disk_name, spec);
+ if (bdev->bd_part->partno) {
+ if (isdigit(hd->disk_name[strlen(hd->disk_name)-1])) {
+ if (buf < end)
+ *buf = 'p';
+ buf++;
+ }
+ buf = number(buf, end, bdev->bd_part->partno, spec);
+ }
+ return buf;
+}
+#endif
+
static noinline_for_stack
char *symbol_string(char *buf, char *end, void *ptr,
struct printf_spec spec, const char *fmt)
@@ -1443,6 +1466,7 @@
* (default assumed to be phys_addr_t, passed by reference)
* - 'd[234]' For a dentry name (optionally 2-4 last components)
* - 'D[234]' Same as 'd' but for a struct file
+ * - 'g' For block_device name (gendisk + partition number)
* - 'C' For a clock, it prints the name (Common Clock Framework) or address
* (legacy clock framework) of the clock
* - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
@@ -1600,6 +1624,11 @@
return dentry_name(buf, end,
((const struct file *)ptr)->f_path.dentry,
spec, fmt);
+#ifdef CONFIG_BLOCK
+ case 'g':
+ return bdev_name(buf, end, ptr, spec, fmt);
+#endif
+
}
spec.flags |= SMALL;
if (spec.field_width == -1) {
