[PATCH v2 0/2] Converge on secs_to_jiffies()

[PATCH v2 0/2] Converge on secs_to_jiffies()

[Easwar Hariharan]

There are ~1150 call sites for msecs_to_jiffies() that:
- Use a multiplier of 1000, or MSEC_PER_SEC, or
- have timeouts that are denominated in seconds, i.e. end in 000

There are yet more sites that use (secs * HZ). Provide secs_to_jiffies()
as a new member of the *_to_jiffies() family and convert a few instances
as a first user.

Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
---
changelog:
v2:
- Add a cover letter
- Define secs_to_jiffies(s) as (s * HZ) instead of msecs_to_jiffies(s * MSEC_PER_SEC) (Anna-Maria)
v1: https://lore.kernel.org/all/20241022185353.2080021-1-eahariha@linux.microsoft.com/
- Move secs_to_jiffies in include/linux/jiffies.h
- Use secs_to_jiffies in drivers/hv
RFC: https://lore.kernel.org/all/20241016223730.531861-1-eahariha@linux.microsoft.com/
- Convert open coded timeouts (secs * HZ) in drivers/hv to msecs_to_jiffies()

---
Easwar Hariharan (2):
      jiffies: Define secs_to_jiffies()
      drivers: hv: Convert open-coded timeouts to secs_to_jiffies()

 drivers/hv/hv_balloon.c   | 9 +++++----
 drivers/hv/hv_kvp.c       | 4 ++--
 drivers/hv/hv_snapshot.c  | 3 ++-
 drivers/hv/vmbus_drv.c    | 2 +-
 include/linux/jiffies.h   | 2 ++
 net/bluetooth/hci_event.c | 2 --
 6 files changed, 12 insertions(+), 10 deletions(-)
---
base-commit: 81983758430957d9a5cb3333fe324fd70cf63e7e
change-id: 20241028-open-coded-timeouts-6dc7cbb6572d

Best regards,
-- 
Easwar Hariharan <eahariha@linux.microsoft.com>

[PATCH v2 1/2] jiffies: Define secs_to_jiffies()

[Easwar Hariharan]

secs_to_jiffies() is defined in hci_event.c and cannot be reused by
other call sites. Hoist it into the core code to allow conversion of the
~1150 usages of msecs_to_jiffies() that either:
- use a multiplier value of 1000 or equivalently MSEC_PER_SEC, or
- have timeouts that are denominated in seconds (i.e. end in 000)

This will also allow conversion of yet more sites that use (sec * HZ)
directly, and improve their readability.

TO: "K. Y. Srinivasan" <kys@microsoft.com>
TO: Haiyang Zhang <haiyangz@microsoft.com>
TO: Wei Liu <wei.liu@kernel.org>
TO: Dexuan Cui <decui@microsoft.com>
TO: linux-hyperv@vger.kernel.org
TO: Anna-Maria Behnsen <anna-maria@linutronix.de>
TO: Thomas Gleixner <tglx@linutronix.de>
TO: Geert Uytterhoeven <geert@linux-m68k.org>
TO: Marcel Holtmann <marcel@holtmann.org>
TO: Johan Hedberg <johan.hedberg@gmail.com>
TO: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
TO: linux-bluetooth@vger.kernel.org
TO: linux-kernel@vger.kernel.org
Suggested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
---
 include/linux/jiffies.h   | 2 ++
 net/bluetooth/hci_event.c | 2 --
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 1220f0fbe5bf..e5256bb5f851 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -526,6 +526,8 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
 	}
 }
 
+#define secs_to_jiffies(_secs) ((_secs) * HZ)
+
 extern unsigned long __usecs_to_jiffies(const unsigned int u);
 #if !(USEC_PER_SEC % HZ)
 static inline unsigned long _usecs_to_jiffies(const unsigned int u)
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 0bbad90ddd6f..7b35c58bbbeb 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -42,8 +42,6 @@
 #define ZERO_KEY "\x00\x00\x00\x00\x00\x00\x00\x00" \
 		 "\x00\x00\x00\x00\x00\x00\x00\x00"
 
-#define secs_to_jiffies(_secs) msecs_to_jiffies((_secs) * 1000)
-
 /* Handle HCI Event packets */
 
 static void *hci_ev_skb_pull(struct hci_dev *hdev, struct sk_buff *skb,

-- 
2.34.1

Re: [PATCH v2 1/2] jiffies: Define secs_to_jiffies()

[Luiz Augusto von Dentz]

Hi Easwar,

On Mon, Oct 28, 2024 at 3:11 PM Easwar Hariharan
<eahariha@linux.microsoft.com> wrote:
>
> secs_to_jiffies() is defined in hci_event.c and cannot be reused by
> other call sites. Hoist it into the core code to allow conversion of the
> ~1150 usages of msecs_to_jiffies() that either:
> - use a multiplier value of 1000 or equivalently MSEC_PER_SEC, or
> - have timeouts that are denominated in seconds (i.e. end in 000)
>
> This will also allow conversion of yet more sites that use (sec * HZ)
> directly, and improve their readability.
>
> TO: "K. Y. Srinivasan" <kys@microsoft.com>
> TO: Haiyang Zhang <haiyangz@microsoft.com>
> TO: Wei Liu <wei.liu@kernel.org>
> TO: Dexuan Cui <decui@microsoft.com>
> TO: linux-hyperv@vger.kernel.org
> TO: Anna-Maria Behnsen <anna-maria@linutronix.de>
> TO: Thomas Gleixner <tglx@linutronix.de>
> TO: Geert Uytterhoeven <geert@linux-m68k.org>
> TO: Marcel Holtmann <marcel@holtmann.org>
> TO: Johan Hedberg <johan.hedberg@gmail.com>
> TO: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> TO: linux-bluetooth@vger.kernel.org
> TO: linux-kernel@vger.kernel.org
> Suggested-by: Michael Kelley <mhklinux@outlook.com>
> Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
> ---
>  include/linux/jiffies.h   | 2 ++
>  net/bluetooth/hci_event.c | 2 --
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
> index 1220f0fbe5bf..e5256bb5f851 100644
> --- a/include/linux/jiffies.h
> +++ b/include/linux/jiffies.h
> @@ -526,6 +526,8 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
>         }
>  }
>
> +#define secs_to_jiffies(_secs) ((_secs) * HZ)
> +
>  extern unsigned long __usecs_to_jiffies(const unsigned int u);
>  #if !(USEC_PER_SEC % HZ)
>  static inline unsigned long _usecs_to_jiffies(const unsigned int u)
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 0bbad90ddd6f..7b35c58bbbeb 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -42,8 +42,6 @@
>  #define ZERO_KEY "\x00\x00\x00\x00\x00\x00\x00\x00" \
>                  "\x00\x00\x00\x00\x00\x00\x00\x00"
>
> -#define secs_to_jiffies(_secs) msecs_to_jiffies((_secs) * 1000)
> -
>  /* Handle HCI Event packets */
>
>  static void *hci_ev_skb_pull(struct hci_dev *hdev, struct sk_buff *skb,
>
> --
> 2.34.1
>

Reviewed-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

-- 
Luiz Augusto von Dentz

Re: [PATCH v2 1/2] jiffies: Define secs_to_jiffies()

[Thomas Gleixner]

On Mon, Oct 28 2024 at 19:11, Easwar Hariharan wrote:
> diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
> index 1220f0fbe5bf..e5256bb5f851 100644
> --- a/include/linux/jiffies.h
> +++ b/include/linux/jiffies.h
> @@ -526,6 +526,8 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
>  	}
>  }
>  
> +#define secs_to_jiffies(_secs) ((_secs) * HZ)

Can you please make that a static inline, as there is no need for macro
magic like in the other conversions, and add a kernel doc comment which
documents this?

Thanks,

        tglx

Re: [PATCH v2 1/2] jiffies: Define secs_to_jiffies()

[Geert Uytterhoeven]

Hi Thomas,

On Tue, Oct 29, 2024 at 5:08 PM Thomas Gleixner <tglx@linutronix.de> wrote:
> On Mon, Oct 28 2024 at 19:11, Easwar Hariharan wrote:
> > diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
> > index 1220f0fbe5bf..e5256bb5f851 100644
> > --- a/include/linux/jiffies.h
> > +++ b/include/linux/jiffies.h
> > @@ -526,6 +526,8 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
> >       }
> >  }
> >
> > +#define secs_to_jiffies(_secs) ((_secs) * HZ)
>
> Can you please make that a static inline, as there is no need for macro
> magic like in the other conversions, and add a kernel doc comment which
> documents this?

Note that a static inline means it cannot be used in e.g. struct initializers,
which are substantial users of  "<value> * HZ".

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2 1/2] jiffies: Define secs_to_jiffies()

[Thomas Gleixner]

On Tue, Oct 29 2024 at 17:22, Geert Uytterhoeven wrote:
> On Tue, Oct 29, 2024 at 5:08 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>> On Mon, Oct 28 2024 at 19:11, Easwar Hariharan wrote:
>> > diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
>> > index 1220f0fbe5bf..e5256bb5f851 100644
>> > --- a/include/linux/jiffies.h
>> > +++ b/include/linux/jiffies.h
>> > @@ -526,6 +526,8 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
>> >       }
>> >  }
>> >
>> > +#define secs_to_jiffies(_secs) ((_secs) * HZ)
>>
>> Can you please make that a static inline, as there is no need for macro
>> magic like in the other conversions, and add a kernel doc comment which
>> documents this?
>
> Note that a static inline means it cannot be used in e.g. struct initializers,
> which are substantial users of  "<value> * HZ".

Bah. That wants to be mentioned in the change log then.

Still the macro should be documented.

Thanks,

        tglx

Re: [PATCH v2 1/2] jiffies: Define secs_to_jiffies()

[Easwar Hariharan]

On 10/29/2024 10:25 AM, Thomas Gleixner wrote:
> On Tue, Oct 29 2024 at 17:22, Geert Uytterhoeven wrote:
>> On Tue, Oct 29, 2024 at 5:08 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>>> On Mon, Oct 28 2024 at 19:11, Easwar Hariharan wrote:
>>>> diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
>>>> index 1220f0fbe5bf..e5256bb5f851 100644
>>>> --- a/include/linux/jiffies.h
>>>> +++ b/include/linux/jiffies.h
>>>> @@ -526,6 +526,8 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
>>>>       }
>>>>  }
>>>>
>>>> +#define secs_to_jiffies(_secs) ((_secs) * HZ)
>>>
>>> Can you please make that a static inline, as there is no need for macro
>>> magic like in the other conversions, and add a kernel doc comment which
>>> documents this?
>>
>> Note that a static inline means it cannot be used in e.g. struct initializers,
>> which are substantial users of  "<value> * HZ".
> 
> Bah. That wants to be mentioned in the change log then.
> 
> Still the macro should be documented.
> 
> Thanks,
> 
>         tglx

Thanks for the review, I'll add a kernel doc in v3 and mention the
limitations of an inline function.

- Easwar

RE: [PATCH v2 1/2] jiffies: Define secs_to_jiffies()

[David Laight]

From: Thomas Gleixner
> Sent: 29 October 2024 17:25
> 
> On Tue, Oct 29 2024 at 17:22, Geert Uytterhoeven wrote:
> > On Tue, Oct 29, 2024 at 5:08 PM Thomas Gleixner <tglx@linutronix.de> wrote:
> >> On Mon, Oct 28 2024 at 19:11, Easwar Hariharan wrote:
> >> > diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
> >> > index 1220f0fbe5bf..e5256bb5f851 100644
> >> > --- a/include/linux/jiffies.h
> >> > +++ b/include/linux/jiffies.h
> >> > @@ -526,6 +526,8 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
> >> >       }
> >> >  }
> >> >
> >> > +#define secs_to_jiffies(_secs) ((_secs) * HZ)
> >>
> >> Can you please make that a static inline, as there is no need for macro
> >> magic like in the other conversions, and add a kernel doc comment which
> >> documents this?
> >
> > Note that a static inline means it cannot be used in e.g. struct initializers,
> > which are substantial users of  "<value> * HZ".
> 
> Bah. That wants to be mentioned in the change log then.
> 
> Still the macro should be documented.

I was wondering if it really had any purpose at all.
It just obfuscates code, doesn't even make it smaller.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

RE: [PATCH v2 1/2] jiffies: Define secs_to_jiffies()

[Thomas Gleixner]

On Wed, Nov 06 2024 at 22:19, David Laight wrote:
> From: Thomas Gleixner
>> Still the macro should be documented.
>
> I was wondering if it really had any purpose at all.
> It just obfuscates code, doesn't even make it smaller.

What is obfuscated here?

secs_to_jiffies() is clearly describing what this is about, while 5 * HZ
is not. Nothing in a driver has to care about the underlying conversion
of a time delta expressed in SI units to a jiffies based time delta.

Thanks,

        tglx

[PATCH v2 2/2] drivers: hv: Convert open-coded timeouts to secs_to_jiffies()

[Easwar Hariharan]

We have several places where timeouts are open-coded as N (seconds) * HZ,
but best practice is to use the utility functions from jiffies.h. Convert
the timeouts to be compliant. This doesn't fix any bugs, it's a simple code
improvement.

TO: "K. Y. Srinivasan" <kys@microsoft.com>
TO: Haiyang Zhang <haiyangz@microsoft.com>
TO: Wei Liu <wei.liu@kernel.org>
TO: Dexuan Cui <decui@microsoft.com>
TO: linux-hyperv@vger.kernel.org
TO: Anna-Maria Behnsen <anna-maria@linutronix.de>
TO: Thomas Gleixner <tglx@linutronix.de>
TO: Geert Uytterhoeven <geert@linux-m68k.org>
TO: Marcel Holtmann <marcel@holtmann.org>
TO: Johan Hedberg <johan.hedberg@gmail.com>
TO: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
TO: linux-bluetooth@vger.kernel.org
TO: linux-kernel@vger.kernel.org
CC: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
---
 drivers/hv/hv_balloon.c  | 9 +++++----
 drivers/hv/hv_kvp.c      | 4 ++--
 drivers/hv/hv_snapshot.c | 3 ++-
 drivers/hv/vmbus_drv.c   | 2 +-
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index c38dcdfcb914..a99112e6f0b8 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -756,7 +756,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
 		 * adding succeeded, it is ok to proceed even if the memory was
 		 * not onlined in time.
 		 */
-		wait_for_completion_timeout(&dm_device.ol_waitevent, 5 * HZ);
+		wait_for_completion_timeout(&dm_device.ol_waitevent, secs_to_jiffies(5));
 		post_status(&dm_device);
 	}
 }
@@ -1373,7 +1373,8 @@ static int dm_thread_func(void *dm_dev)
 	struct hv_dynmem_device *dm = dm_dev;
 
 	while (!kthread_should_stop()) {
-		wait_for_completion_interruptible_timeout(&dm_device.config_event, 1 * HZ);
+		wait_for_completion_interruptible_timeout(&dm_device.config_event,
+								secs_to_jiffies(1));
 		/*
 		 * The host expects us to post information on the memory
 		 * pressure every second.
@@ -1748,7 +1749,7 @@ static int balloon_connect_vsp(struct hv_device *dev)
 	if (ret)
 		goto out;
 
-	t = wait_for_completion_timeout(&dm_device.host_event, 5 * HZ);
+	t = wait_for_completion_timeout(&dm_device.host_event, secs_to_jiffies(5));
 	if (t == 0) {
 		ret = -ETIMEDOUT;
 		goto out;
@@ -1806,7 +1807,7 @@ static int balloon_connect_vsp(struct hv_device *dev)
 	if (ret)
 		goto out;
 
-	t = wait_for_completion_timeout(&dm_device.host_event, 5 * HZ);
+	t = wait_for_completion_timeout(&dm_device.host_event, secs_to_jiffies(5));
 	if (t == 0) {
 		ret = -ETIMEDOUT;
 		goto out;
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index d35b60c06114..29e01247a087 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -655,7 +655,7 @@ void hv_kvp_onchannelcallback(void *context)
 		if (host_negotiatied == NEGO_NOT_STARTED) {
 			host_negotiatied = NEGO_IN_PROGRESS;
 			schedule_delayed_work(&kvp_host_handshake_work,
-				      HV_UTIL_NEGO_TIMEOUT * HZ);
+						secs_to_jiffies(HV_UTIL_NEGO_TIMEOUT));
 		}
 		return;
 	}
@@ -724,7 +724,7 @@ void hv_kvp_onchannelcallback(void *context)
 		 */
 		schedule_work(&kvp_sendkey_work);
 		schedule_delayed_work(&kvp_timeout_work,
-					HV_UTIL_TIMEOUT * HZ);
+				      secs_to_jiffies(HV_UTIL_TIMEOUT));
 
 		return;
 
diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 0d2184be1691..86d87486ed40 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -193,7 +193,8 @@ static void vss_send_op(void)
 	vss_transaction.state = HVUTIL_USERSPACE_REQ;
 
 	schedule_delayed_work(&vss_timeout_work, op == VSS_OP_FREEZE ?
-			VSS_FREEZE_TIMEOUT * HZ : HV_UTIL_TIMEOUT * HZ);
+				secs_to_jiffies(VSS_FREEZE_TIMEOUT) :
+				secs_to_jiffies(HV_UTIL_TIMEOUT));
 
 	rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg), NULL);
 	if (rc) {
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 9b15f7daf505..7db30881e83a 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2507,7 +2507,7 @@ static int vmbus_bus_resume(struct device *dev)
 	vmbus_request_offers();
 
 	if (wait_for_completion_timeout(
-		&vmbus_connection.ready_for_resume_event, 10 * HZ) == 0)
+		&vmbus_connection.ready_for_resume_event, secs_to_jiffies(10)) == 0)
 		pr_err("Some vmbus device is missing after suspending?\n");
 
 	/* Reset the event for the next suspend. */

-- 
2.34.1