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authorDmitry Monakhov <dmonakhov@openvz.org>2015-04-13 15:31:35 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2016-01-06 20:55:29 +0300
commit1031bc589228ca35b3b6fb3dfe4656c0da5fbeb4 (patch)
tree52ad94e769ee16491c9db4e9904ac266292e4996 /lib/vsprintf.c
parent424081f3c881ca3aef50cfa571e91863c10d952a (diff)
downloadlinux-1031bc589228ca35b3b6fb3dfe4656c0da5fbeb4.tar.xz
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>
Diffstat (limited to 'lib/vsprintf.c')
-rw-r--r--lib/vsprintf.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index f9cee8e1233c..ac3f9476b776 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 @@ char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_sp
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 @@ int kptr_restrict __read_mostly;
* (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 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
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) {