Thread (26 messages) 26 messages, 7 authors, 2020-10-23

Re: [patch 11/12] usb: core: Replace in_interrupt() in comments

From: Alan Stern <stern@rowland.harvard.edu>
Date: 2020-10-14 16:27:28
Also in: linux-omap, linux-samsung-soc, linux-usb, lkml

On Wed, Oct 14, 2020 at 04:52:26PM +0200, Thomas Gleixner wrote:
From: Ahmed S. Darwish <redacted>

The usage of in_interrupt() in drivers is phased out for various reasons.

Various comments use !in_interrupt() to describe calling context for
functions which might sleep. That's wrong because the calling context has
to be preemptible task context, which is not what !in_interrupt()
describes.

Replace !in_interrupt() with more accurate plain text descriptions.

The comment for usb_hcd_poll_rh_status() is misleading as this function is
called from all kinds of contexts including preemptible task
context. Remove it as there is obviously no restriction.

Signed-off-by: Ahmed S. Darwish <redacted>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <redacted>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org

---
quoted hunk ↗ jump to hunk
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -746,9 +746,6 @@ static int rh_call_control (struct usb_h
  * Root Hub interrupt transfers are polled using a timer if the
  * driver requests it; otherwise the driver is responsible for
  * calling usb_hcd_poll_rh_status() when an event occurs.
- *
- * Completions are called in_interrupt(), but they may or may not
- * be in_irq().
This comment should not be removed; instead it should be changed to say 
that completion handlers are called with interrupts disabled.
quoted hunk ↗ jump to hunk
@@ -1691,7 +1690,6 @@ static void usb_giveback_urb_bh(unsigned
  * @hcd: host controller returning the URB
  * @urb: urb being returned to the USB device driver.
  * @status: completion status code for the URB.
- * Context: in_interrupt()
The comment should be changed to say that the routine runs in a BH 
handler (or however you want to express it).
quoted hunk ↗ jump to hunk
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
quoted hunk ↗ jump to hunk
@@ -934,7 +939,7 @@ int usb_get_device_descriptor(struct usb
 /*
  * usb_set_isoch_delay - informs the device of the packet transmit delay
  * @dev: the device whose delay is to be informed
- * Context: !in_interrupt()
+ * Context: can sleep
Why is this comment different from all the others?

Alan Stern

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