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

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Date:   Wed, 28 Apr 2021 21:59:27 +0800
From:   Jia He <justin.he@....com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Jonathan Corbet <corbet@....net>,
        Luca Coelho <luciano.coelho@...el.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>
Cc:     Christian Borntraeger <borntraeger@...ibm.com>,
        Johannes Berg <johannes.berg@...el.com>,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        linux-s390@...r.kernel.org, Jia He <justin.he@....com>
Subject: [PATCH 2/4] lib/vsprintf.c: Make %p{D,d} mean as much components as possible

From: Linus Torvalds <torvalds@...ux-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@...ux-foundation.org>
Signed-off-by: Jia He <justin.he@....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