From patchwork Mon Oct 19 10:06:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 11843971 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EDCE716BC for ; Mon, 19 Oct 2020 10:18:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3F97222EC for ; Mon, 19 Oct 2020 10:18:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="id4u0jOm"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="AUtXDL7C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728060AbgJSKSv (ORCPT ); Mon, 19 Oct 2020 06:18:51 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:58846 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729239AbgJSKSU (ORCPT ); Mon, 19 Oct 2020 06:18:20 -0400 Message-Id: <20201019101110.851821025@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1603102696; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=vDj3POLlE65OYJ5MWA23dfiuTv+9arU7n7S2hfU4NfM=; b=id4u0jOm7ZnFZD2vWTPwwiFPGCHHN0GNhGdEZGVx3mKjZ78wHR9BB1WcYhQvY4wuaOHe0d IaGEmf5zUGLMbJ+lqw50JUHZ4wjpugWf2UxjtIt97K51AGi8Z7oX9l5iFFjE4WmMCxbn/F dXDx1MEcEpn/zcMmfQMfUEYEKZsAM1Qp0rgZwmuhWTvrBiwa2kZwmmz4OmvIMmdOo/gsU9 hMbokbnrNeuQEV+gEKhHXnxRQNIQKdR9xlPU0B5LpWKYyIMUmMYcm/S69baXmUdd/hhjIQ 1+eJkESSzV4Wv3FLrZepxjcPUikJg90RIGgFOJqW7qL7kLGVzFBVuOsV195Xog== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1603102696; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=vDj3POLlE65OYJ5MWA23dfiuTv+9arU7n7S2hfU4NfM=; b=AUtXDL7CKtW36iHy6ghf3uYZxa9oFrkz7w4h1RAt9fxXZRoZlYabnFk2gaM+zHCVdQkLzF EWPT9MGs1ENYR6DQ== Date: Mon, 19 Oct 2020 12:06:41 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , "Ahmed S. Darwish" , Sebastian Andrzej Siewior , Greg Kroah-Hartman , linux-usb@vger.kernel.org, Thomas Winischhofer , Johan Hovold , Mathias Nyman , Valentina Manea , Shuah Khan , Alan Stern , linux-omap@vger.kernel.org, Kukjin Kim , Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Felipe Balbi , Duncan Sands Subject: [patch V2 12/13] usb: core: Replace in_interrupt() in comments References: <20201019100629.419020859@linutronix.de> MIME-Version: 1.0 Content-transfer-encoding: 8-bit Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org From: Ahmed S. Darwish 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 Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org Acked-by: Alan Stern --- V2: Fixup the comments according to review (Alan) --- drivers/usb/core/buffer.c | 6 ++++-- drivers/usb/core/hcd-pci.c | 6 ++++-- drivers/usb/core/hcd.c | 26 +++++++++++++++++--------- drivers/usb/core/hub.c | 3 ++- drivers/usb/core/message.c | 35 ++++++++++++++++++++++------------- drivers/usb/core/usb.c | 4 ++-- 6 files changed, 51 insertions(+), 29 deletions(-) --- a/drivers/usb/core/buffer.c +++ b/drivers/usb/core/buffer.c @@ -51,7 +51,8 @@ void __init usb_init_pool_max(void) /** * 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 @@ -88,7 +89,8 @@ int hcd_buffer_create(struct usb_hcd *hc /** * 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(). */ --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -160,7 +160,8 @@ static void ehci_wait_for_companions(str * @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 @@ -304,7 +305,8 @@ EXPORT_SYMBOL_GPL(usb_hcd_pci_probe); /** * 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 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -747,8 +747,7 @@ static int rh_call_control (struct usb_h * 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) { @@ -904,7 +903,8 @@ static void usb_bus_init (struct usb_bus /** * 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. @@ -939,7 +939,8 @@ static int usb_register_bus(struct usb_b /** * 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. @@ -1691,7 +1692,11 @@ 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() + * + * 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 @@ -2268,7 +2273,7 @@ EXPORT_SYMBOL_GPL(usb_hcd_resume_root_hu * 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. @@ -2474,7 +2479,8 @@ EXPORT_SYMBOL_GPL(__usb_create_hcd); * @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 @@ -2496,7 +2502,8 @@ EXPORT_SYMBOL_GPL(usb_create_shared_hcd) * @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 @@ -2830,7 +2837,8 @@ EXPORT_SYMBOL_GPL(usb_add_hcd); /** * 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. --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2171,7 +2171,8 @@ static void hub_disconnect_children(stru /** * 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. * --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -119,7 +119,7 @@ static int usb_internal_control_msg(stru * @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. @@ -173,7 +173,7 @@ EXPORT_SYMBOL_GPL(usb_control_msg); * @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. @@ -206,7 +206,7 @@ EXPORT_SYMBOL_GPL(usb_interrupt_msg); * @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. @@ -473,7 +473,8 @@ EXPORT_SYMBOL_GPL(usb_sg_init); * 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 @@ -627,7 +628,8 @@ EXPORT_SYMBOL_GPL(usb_sg_cancel); * @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 @@ -675,7 +677,8 @@ EXPORT_SYMBOL_GPL(usb_get_descriptor); * @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). @@ -810,7 +813,8 @@ static int usb_get_langid(struct usb_dev * @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 @@ -899,7 +903,8 @@ char *usb_cache_string(struct usb_device * 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. @@ -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: task context, might sleep * * Since this is an optional request, we don't bother if it fails. */ @@ -962,7 +967,8 @@ int usb_set_isoch_delay(struct usb_devic * @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 @@ -1039,7 +1045,8 @@ EXPORT_SYMBOL_GPL(usb_get_status); * 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 @@ -1343,7 +1350,8 @@ void usb_enable_interface(struct usb_dev * @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. @@ -1762,7 +1770,8 @@ static void __usb_queue_reset_device(str * 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 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -28,7 +28,6 @@ #include #include #include -#include /* for in_interrupt() */ #include #include #include @@ -561,7 +560,8 @@ static bool usb_dev_authorized(struct us * @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.