2021-04-28 14:55:43

by Jia He

[permalink] [raw]
Subject: [PATCH 1/4] iwlwifi: mvm: Explicitly use %pd1 in debugfs entry

'%pd'(no digit following) will mean to print last 4 components of file
dentry. Hence explicitly use %pd1 instead.

Signed-off-by: Jia He <[email protected]>
---
drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
index 38d0bfb649cc..41ccbb4286c2 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
@@ -752,7 +752,7 @@ void iwl_mvm_vif_dbgfs_register(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
* find
* netdev:wlan0 -> ../../../ieee80211/phy0/netdev:wlan0/iwlmvm/
*/
- snprintf(buf, 100, "../../../%pd3/%pd",
+ snprintf(buf, 100, "../../../%pd3/%pd1",
dbgfs_dir,
mvmvif->dbgfs_dir);

--
2.17.1


2021-04-28 14:55:47

by Jia He

[permalink] [raw]
Subject: [PATCH 3/4] s390/hmcdrv: Remove the redundant directory path in debug message

It would be better to use full file path with '%pD' instead of hard coding.

Signed-off-by: Jia He <[email protected]>
---
drivers/s390/char/hmcdrv_dev.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/char/hmcdrv_dev.c b/drivers/s390/char/hmcdrv_dev.c
index 20e9cd542e03..cdde75508c8a 100644
--- a/drivers/s390/char/hmcdrv_dev.c
+++ b/drivers/s390/char/hmcdrv_dev.c
@@ -137,7 +137,7 @@ static int hmcdrv_dev_open(struct inode *inode, struct file *fp)
if (rc)
module_put(THIS_MODULE);

- pr_debug("open file '/dev/%pD' with return code %d\n", fp, rc);
+ pr_debug("open file '%pD' with return code %d\n", fp, rc);
return rc;
}

@@ -146,7 +146,7 @@ static int hmcdrv_dev_open(struct inode *inode, struct file *fp)
*/
static int hmcdrv_dev_release(struct inode *inode, struct file *fp)
{
- pr_debug("closing file '/dev/%pD'\n", fp);
+ pr_debug("closing file '%pD'\n", fp);
kfree(fp->private_data);
fp->private_data = NULL;
hmcdrv_ftp_shutdown();
@@ -231,7 +231,7 @@ static ssize_t hmcdrv_dev_read(struct file *fp, char __user *ubuf,
retlen = hmcdrv_dev_transfer((char *) fp->private_data,
*pos, ubuf, len);

- pr_debug("read from file '/dev/%pD' at %lld returns %zd/%zu\n",
+ pr_debug("read from file '%pD' at %lld returns %zd/%zu\n",
fp, (long long) *pos, retlen, len);

if (retlen > 0)
@@ -248,7 +248,7 @@ static ssize_t hmcdrv_dev_write(struct file *fp, const char __user *ubuf,
{
ssize_t retlen;

- pr_debug("writing file '/dev/%pD' at pos. %lld with length %zd\n",
+ pr_debug("writing file '%pD' at pos. %lld with length %zd\n",
fp, (long long) *pos, len);

if (!fp->private_data) { /* first expect a cmd write */
@@ -272,7 +272,7 @@ static ssize_t hmcdrv_dev_write(struct file *fp, const char __user *ubuf,
if (retlen > 0)
*pos += retlen;

- pr_debug("write to file '/dev/%pD' returned %zd\n", fp, retlen);
+ pr_debug("write to file '%pD' returned %zd\n", fp, retlen);

return retlen;
}
--
2.17.1

2021-04-28 14:55:51

by Jia He

[permalink] [raw]
Subject: [PATCH 4/4] lib/test_printf: Explicitly add components number to %pD and %pd

After changing the default components number from 1 to 4 for %pD
and %pd, it would be better to explicitly add the number in test_printf
cases.

Add a test case of %pd5 to verify if it can be capped by 4 components.

Signed-off-by: Jia He <[email protected]>
---
lib/test_printf.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/test_printf.c b/lib/test_printf.c
index 27b964ec723d..899cd55d1c90 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -478,18 +478,20 @@ static struct dentry test_dentry[4] __initdata = {
static void __init
dentry(void)
{
- test("foo", "%pd", &test_dentry[0]);
+ test("foo", "%pd1", &test_dentry[0]);
test("foo", "%pd2", &test_dentry[0]);

- test("(null)", "%pd", NULL);
- test("(efault)", "%pd", PTR_INVALID);
- test("(null)", "%pD", NULL);
- test("(efault)", "%pD", PTR_INVALID);
+ test("(null)", "%pd1", NULL);
+ test("(efault)", "%pd1", PTR_INVALID);
+ test("(null)", "%pD1", NULL);
+ test("(efault)", "%pD1", PTR_INVALID);

- test("romeo", "%pd", &test_dentry[3]);
+ test("romeo", "%pd1", &test_dentry[3]);
test("alfa/romeo", "%pd2", &test_dentry[3]);
test("bravo/alfa/romeo", "%pd3", &test_dentry[3]);
test("/bravo/alfa/romeo", "%pd4", &test_dentry[3]);
+ test("/bravo/alfa/romeo", "%pd", &test_dentry[3]);
+ test("/bravo/alfa/romeo", "%pd5", &test_dentry[3]);
test("/bravo/alfa", "%pd4", &test_dentry[2]);

test("bravo/alfa |bravo/alfa ", "%-12pd2|%*pd2", &test_dentry[2], -12, &test_dentry[2]);
--
2.17.1

2021-04-28 14:57:48

by Jia He

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

From: Linus Torvalds <[email protected]>

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 <[email protected]>
Signed-off-by: Jia He <[email protected]>
---
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

2021-04-28 15:11:38

by Andy Shevchenko

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

On Wed, Apr 28, 2021 at 5:56 PM Jia He <[email protected]> wrote:
>
> From: Linus Torvalds <[email protected]>

Hmm... Okay.

> 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).

Sorry, but from above I didn't get why.

The commit message tells only about %pD, but patch changes behaviour
of the ~100 or so users of "%pd" without any explanation.

Besides that the patch is prepended only by one change (which is also
not related to %pD), while we have ~30 users which behaviour got
changed.


--
With Best Regards,
Andy Shevchenko

2021-04-29 08:55:30

by Andy Shevchenko

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

On Thu, Apr 29, 2021 at 11:47 AM Petr Mladek <[email protected]> wrote:
>
> On Wed 2021-04-28 21:59:27, Jia He wrote:
> > From: Linus Torvalds <[email protected]>
> >
> > 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).
>
> Could you please provide link to the discussion where this idea was
> came from?

https://lore.kernel.org/lkml/[email protected]/

--
With Best Regards,
Andy Shevchenko

2021-04-29 09:25:34

by Petr Mladek

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

On Thu 2021-04-29 11:52:49, Andy Shevchenko wrote:
> On Thu, Apr 29, 2021 at 11:47 AM Petr Mladek <[email protected]> wrote:
> >
> > On Wed 2021-04-28 21:59:27, Jia He wrote:
> > > From: Linus Torvalds <[email protected]>
> > >
> > > 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).
> >
> > Could you please provide link to the discussion where this idea was
> > came from?
>
> https://lore.kernel.org/lkml/[email protected]/

Thanks for the link. I see that it was not clear whether the patch
was good for %pd behavior.

Linus actually suggests to keep %pd behavior as it was before, see
https://lore.kernel.org/lkml/[email protected]om/

Well, I think that this is up to the file system developers to decide.
I am not sure if the path would do more harm than good,
or vice versa, for dentry names.

Best Regards,
Petr

2021-04-30 01:36:51

by Jia He

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

Hi

> -----Original Message-----
> From: Petr Mladek <[email protected]>
> Sent: Thursday, April 29, 2021 5:25 PM
> To: Andy Shevchenko <[email protected]>
> Cc: Justin He <[email protected]>; Linus Torvalds <[email protected]
> foundation.org>; Steven Rostedt <[email protected]>; Sergey Senozhatsky
> <[email protected]>; Andy Shevchenko
> <[email protected]>; Rasmus Villemoes
> <[email protected]>; Jonathan Corbet <[email protected]>; Luca Coelho
> <[email protected]>; Kalle Valo <[email protected]>; David S.
> Miller <[email protected]>; Jakub Kicinski <[email protected]>; Heiko
> Carstens <[email protected]>; Vasily Gorbik <[email protected]>; Christian
> Borntraeger <[email protected]>; Johannes Berg
> <[email protected]>; Linux Documentation List <linux-
> [email protected]>; Linux Kernel Mailing List <linux-
> [email protected]>; open list:TI WILINK WIRELES... <linux-
> [email protected]>; netdev <[email protected]>; linux-
> [email protected]
> Subject: Re: [PATCH 2/4] lib/vsprintf.c: Make %p{D,d} mean as much
> components as possible
>
> On Thu 2021-04-29 11:52:49, Andy Shevchenko wrote:
> > On Thu, Apr 29, 2021 at 11:47 AM Petr Mladek <[email protected]> wrote:
> > >
> > > On Wed 2021-04-28 21:59:27, Jia He wrote:
> > > > From: Linus Torvalds <[email protected]>
> > > >
> > > > 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).
> > >
> > > Could you please provide link to the discussion where this idea was
> > > came from?
> >
> > https://lore.kernel.org/lkml/[email protected]/
>
> Thanks for the link. I see that it was not clear whether the patch
> was good for %pd behavior.
>
> Linus actually suggests to keep %pd behavior as it was before, see
> https://lore.kernel.org/lkml/CAHk-=wimsMqGdzik187YWLb-
> [email protected]/

Okay, let me keep the default %pd behavior as before('%pd' is '%pd1') and
change the behavior of %pD ('%pD' is '%pD4')

--
Cheers,
Justin (Jia He)
>
> Well, I think that this is up to the file system developers to decide.
> I am not sure if the path would do more harm than good,
> or vice versa, for dentry names.
>
> Best Regards,
> Petr
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