usb: core: Replace in_interrupt() in comments

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 <[e-mail]>
Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Acked-by: Alan Stern <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/core/buffer.c

···
 /**
  * hcd_buffer_create - initialize buffer pools
  * @hcd: the bus whose buffer pools are to be initialized
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep
  *
  * Call this as part of initializing a host controller that uses the dma
  * memory allocators.  It initializes some pools of dma-coherent memory that
···
 /**
  * hcd_buffer_destroy - deallocate buffer pools
  * @hcd: the bus whose buffer pools are to be destroyed
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep
  *
  * This frees the buffer pools created by hcd_buffer_create().
  */

drivers/usb/core/hcd-pci.c

···
  * @dev: USB Host Controller being probed
  * @id: pci hotplug id connecting controller to HCD framework
  * @driver: USB HC driver handle
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep
  *
  * Allocates basic PCI resources for this USB host controller, and
  * then invokes the start() method for the HCD associated with it
···
 /**
  * usb_hcd_pci_remove - shutdown processing for PCI-based HCDs
  * @dev: USB Host Controller being removed
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep
  *
  * Reverses the effect of usb_hcd_pci_probe(), first invoking
  * the HCD's stop() method.  It is always called from a thread

drivers/usb/core/hcd.c

···
  * 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().
+ * Completion handler may not sleep. See usb_hcd_giveback_urb() for details.
  */
 void usb_hcd_poll_rh_status(struct usb_hcd *hcd)
 {
···
 /**
  * usb_register_bus - registers the USB host controller with the usb core
  * @bus: pointer to the bus to register
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep.
  *
  * Assigns a bus number, and links the controller into usbcore data
  * structures so that it can be seen by scanning the bus list.
···
 /**
  * usb_deregister_bus - deregisters the USB host controller
  * @bus: pointer to the bus to deregister
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep.
  *
  * Recycles the bus number, and unlinks the controller from usbcore data
  * structures so that it won't be seen by scanning the bus list.
···
  * @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()
+ *
+ * Context: atomic. The completion callback is invoked in caller's context.
+ * For HCDs with HCD_BH flag set, the completion callback is invoked in tasklet
+ * context (except for URBs submitted to the root hub which always complete in
+ * caller's context).
  *
  * This hands the URB from HCD to its USB device driver, using its
  * completion function.  The HCD has freed all per-urb resources
···
  * usb_bus_start_enum - start immediate enumeration (for OTG)
  * @bus: the bus (must use hcd framework)
  * @port_num: 1-based number of port; usually bus->otg_port
- * Context: in_interrupt()
+ * Context: atomic
  *
  * Starts enumeration, with an immediate reset followed later by
  * hub_wq identifying and possibly configuring the device.
···
  * @bus_name: value to store in hcd->self.bus_name
  * @primary_hcd: a pointer to the usb_hcd structure that is sharing the
  *              PCI device.  Only allocate certain resources for the primary HCD
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep.
  *
  * Allocate a struct usb_hcd, with extra space at the end for the
  * HC driver's private data.  Initialize the generic members of the
···
  * @driver: HC driver that will use this hcd
  * @dev: device for this HC, stored in hcd->self.controller
  * @bus_name: value to store in hcd->self.bus_name
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep.
  *
  * Allocate a struct usb_hcd, with extra space at the end for the
  * HC driver's private data.  Initialize the generic members of the
···
 /**
  * usb_remove_hcd - shutdown processing for generic HCDs
  * @hcd: the usb_hcd structure to remove
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep.
  *
  * Disconnects the root hub, then reverses the effects of usb_add_hcd(),
  * invoking the HCD's stop() method.

drivers/usb/core/hub.c

···
 /**
  * usb_disconnect - disconnect a device (usbcore-internal)
  * @pdev: pointer to device being disconnected
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep
  *
  * Something got disconnected. Get rid of it and all of its children.
  *

drivers/usb/core/message.c

···
  * @timeout: time in msecs to wait for the message to complete before timing
  *	out (if 0 the wait is forever)
  *
- * Context: !in_interrupt ()
+ * Context: task context, might sleep.
  *
  * This function sends a simple control message to a specified endpoint and
  * waits for the message to complete, or timeout.
···
  * @timeout: time in msecs to wait for the message to complete before
  *	timing out (if 0 the wait is forever)
  *
- * Context: !in_interrupt ()
+ * Context: task context, might sleep.
  *
  * This function sends a simple interrupt message to a specified endpoint and
  * waits for the message to complete, or timeout.
···
  * @timeout: time in msecs to wait for the message to complete before
  *	timing out (if 0 the wait is forever)
  *
- * Context: !in_interrupt ()
+ * Context: task context, might sleep.
  *
  * This function sends a simple bulk message to a specified endpoint
  * and waits for the message to complete, or timeout.
···
  * usb_sg_wait - synchronously execute scatter/gather request
  * @io: request block handle, as initialized with usb_sg_init().
  * 	some fields become accessible when this call returns.
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep.
  *
  * This function blocks until the specified I/O operation completes.  It
  * leverages the grouping of the related I/O requests to get good transfer
···
  * @index: the number of the descriptor
  * @buf: where to put the descriptor
  * @size: how big is "buf"?
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep.
  *
  * Gets a USB descriptor.  Convenience functions exist to simplify
  * getting some types of descriptors.  Use
···
  * @index: the number of the descriptor
  * @buf: where to put the string
  * @size: how big is "buf"?
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep.
  *
  * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
  * in little-endian byte order).
···
  * @index: the number of the descriptor
  * @buf: where to put the string
  * @size: how big is "buf"?
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep.
  *
  * This converts the UTF-16LE encoded strings returned by devices, from
  * usb_get_string_descriptor(), to null-terminated UTF-8 encoded ones
···
  * usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
  * @dev: the device whose device descriptor is being updated
  * @size: how much of the descriptor to read
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep.
  *
  * Updates the copy of the device descriptor stored in the device structure,
  * which dedicates space for this purpose.
···
 /*
  * 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: task context, might sleep
  *
  * Since this is an optional request, we don't bother if it fails.
  */
···
  * @type: USB_STATUS_TYPE_*; for standard or PTM status types
  * @target: zero (for device), else interface or endpoint number
  * @data: pointer to two bytes of bitmap data
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep.
  *
  * Returns device, interface, or endpoint status.  Normally only of
  * interest to see if the device is self powered, or has enabled the
···
  * usb_clear_halt - tells device to clear endpoint halt/stall condition
  * @dev: device whose endpoint is halted
  * @pipe: endpoint "pipe" being cleared
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep.
  *
  * This is used to clear halt conditions for bulk and interrupt endpoints,
  * as reported by URB completion status.  Endpoints that are halted are
···
  * @dev: the device whose interface is being updated
  * @interface: the interface being updated
  * @alternate: the setting being chosen.
- * Context: !in_interrupt ()
+ *
+ * Context: task context, might sleep.
  *
  * This is used to enable data transfers on interfaces that may not
  * be enabled by default.  Not all devices support such configurability.
···
  * usb_set_configuration - Makes a particular device setting be current
  * @dev: the device whose configuration is being updated
  * @configuration: the configuration being chosen.
- * Context: !in_interrupt(), caller owns the device lock
+ *
+ * Context: task context, might sleep. Caller holds device lock.
  *
  * This is used to enable non-default device modes.  Not all devices
  * use this kind of configurability; many devices only have one

drivers/usb/core/usb.c

···
 #include <linux/string.h>
 #include <linux/bitops.h>
 #include <linux/slab.h>
-#include <linux/interrupt.h>  /* for in_interrupt() */
 #include <linux/kmod.h>
 #include <linux/init.h>
 #include <linux/spinlock.h>
···
  * @parent: hub to which device is connected; null to allocate a root hub
  * @bus: bus used to access the device
  * @port1: one-based index of port; ignored for root hubs
- * Context: !in_interrupt()
+ *
+ * Context: task context, might sleep.
  *
  * Only hub drivers (including virtual root hub drivers for host
  * controllers) should ever call this.