[PATCH 2/4] lib/vsprintf.c: Make %p{D,d} mean as much components as possible

Jia He
2021-04-28T13:59:55Z

From: Linus Torvalds <torvalds@linux-foundation.org>

We have '%pD'(no digit following) for printing a filename. It may not be
perfect (by default it only prints one component.

%pD4 should be more than good enough, but we should make plain "%pD" mean
"as much of the path that is reasonable" rather than "as few components as
possible" (ie 1).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jia He <justin.he@arm.com>
---
Documentation/core-api/printk-formats.rst | 3 ++-
lib/vsprintf.c | 4 ++--
2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index 9be6de402cb9..aa76cbec0dae 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -413,7 +413,8 @@ dentry names
For printing dentry name; if we race with :c:func:`d_move`, the name might
be a mix of old and new ones, but it won't oops. %pd dentry is a safer
equivalent of %s dentry->d_name.name we used to use, %pd<n> prints ``n``
-last components. %pD does the same thing for struct file.
+last components. %pD does the same thing for struct file. By default, %p{D,d}
+is equal to %p{D,d}4.

Passed by reference.

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 6c56c62fd9a5..5b563953f970 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -880,11 +880,11 @@ char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_sp
int i, n;

switch (fmt[1]) {
- case '2': case '3': case '4':
+ case '1': case '2': case '3': case '4':
depth = fmt[1] - '0';
break;
default:
- depth = 1;
+ depth = 4;
}

rcu_read_lock();
--
2.17.1