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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 17:16:41 +07:00
8815bb09af
On some HCDs usb_unlink_urb() can directly call the completion handler. That limits the spinlocks that can be taken in the handler to locks not held while calling usb_unlink_urb() To prevent a race with resubmission, this patch exposes usbcore's infrastructure for blocking submission, uses it and so drops the lock without causing a race in usbhid. Signed-off-by: Oliver Neukum <oneukum@suse.de> Acked-by: Jiri Kosina <jkosina@suse.cz> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
889 lines
29 KiB
C
889 lines
29 KiB
C
#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/bitops.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/log2.h>
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#include <linux/usb.h>
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#include <linux/wait.h>
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#include <linux/usb/hcd.h>
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#define to_urb(d) container_of(d, struct urb, kref)
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static void urb_destroy(struct kref *kref)
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{
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struct urb *urb = to_urb(kref);
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if (urb->transfer_flags & URB_FREE_BUFFER)
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kfree(urb->transfer_buffer);
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kfree(urb);
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}
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/**
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* usb_init_urb - initializes a urb so that it can be used by a USB driver
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* @urb: pointer to the urb to initialize
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*
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* Initializes a urb so that the USB subsystem can use it properly.
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*
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* If a urb is created with a call to usb_alloc_urb() it is not
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* necessary to call this function. Only use this if you allocate the
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* space for a struct urb on your own. If you call this function, be
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* careful when freeing the memory for your urb that it is no longer in
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* use by the USB core.
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*
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* Only use this function if you _really_ understand what you are doing.
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*/
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void usb_init_urb(struct urb *urb)
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{
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if (urb) {
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memset(urb, 0, sizeof(*urb));
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kref_init(&urb->kref);
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INIT_LIST_HEAD(&urb->anchor_list);
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}
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}
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EXPORT_SYMBOL_GPL(usb_init_urb);
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/**
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* usb_alloc_urb - creates a new urb for a USB driver to use
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* @iso_packets: number of iso packets for this urb
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* @mem_flags: the type of memory to allocate, see kmalloc() for a list of
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* valid options for this.
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*
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* Creates an urb for the USB driver to use, initializes a few internal
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* structures, incrementes the usage counter, and returns a pointer to it.
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*
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* If no memory is available, NULL is returned.
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*
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* If the driver want to use this urb for interrupt, control, or bulk
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* endpoints, pass '0' as the number of iso packets.
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*
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* The driver must call usb_free_urb() when it is finished with the urb.
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*/
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struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
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{
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struct urb *urb;
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urb = kmalloc(sizeof(struct urb) +
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iso_packets * sizeof(struct usb_iso_packet_descriptor),
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mem_flags);
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if (!urb) {
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printk(KERN_ERR "alloc_urb: kmalloc failed\n");
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return NULL;
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}
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usb_init_urb(urb);
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return urb;
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}
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EXPORT_SYMBOL_GPL(usb_alloc_urb);
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/**
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* usb_free_urb - frees the memory used by a urb when all users of it are finished
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* @urb: pointer to the urb to free, may be NULL
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*
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* Must be called when a user of a urb is finished with it. When the last user
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* of the urb calls this function, the memory of the urb is freed.
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*
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* Note: The transfer buffer associated with the urb is not freed unless the
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* URB_FREE_BUFFER transfer flag is set.
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*/
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void usb_free_urb(struct urb *urb)
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{
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if (urb)
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kref_put(&urb->kref, urb_destroy);
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}
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EXPORT_SYMBOL_GPL(usb_free_urb);
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/**
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* usb_get_urb - increments the reference count of the urb
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* @urb: pointer to the urb to modify, may be NULL
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*
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* This must be called whenever a urb is transferred from a device driver to a
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* host controller driver. This allows proper reference counting to happen
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* for urbs.
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*
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* A pointer to the urb with the incremented reference counter is returned.
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*/
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struct urb *usb_get_urb(struct urb *urb)
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{
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if (urb)
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kref_get(&urb->kref);
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return urb;
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}
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EXPORT_SYMBOL_GPL(usb_get_urb);
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/**
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* usb_anchor_urb - anchors an URB while it is processed
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* @urb: pointer to the urb to anchor
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* @anchor: pointer to the anchor
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*
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* This can be called to have access to URBs which are to be executed
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* without bothering to track them
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*/
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void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
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{
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unsigned long flags;
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spin_lock_irqsave(&anchor->lock, flags);
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usb_get_urb(urb);
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list_add_tail(&urb->anchor_list, &anchor->urb_list);
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urb->anchor = anchor;
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if (unlikely(anchor->poisoned)) {
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atomic_inc(&urb->reject);
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}
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spin_unlock_irqrestore(&anchor->lock, flags);
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}
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EXPORT_SYMBOL_GPL(usb_anchor_urb);
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/* Callers must hold anchor->lock */
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static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor)
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{
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urb->anchor = NULL;
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list_del(&urb->anchor_list);
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usb_put_urb(urb);
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if (list_empty(&anchor->urb_list))
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wake_up(&anchor->wait);
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}
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/**
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* usb_unanchor_urb - unanchors an URB
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* @urb: pointer to the urb to anchor
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*
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* Call this to stop the system keeping track of this URB
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*/
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void usb_unanchor_urb(struct urb *urb)
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{
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unsigned long flags;
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struct usb_anchor *anchor;
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if (!urb)
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return;
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anchor = urb->anchor;
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if (!anchor)
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return;
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spin_lock_irqsave(&anchor->lock, flags);
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/*
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* At this point, we could be competing with another thread which
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* has the same intention. To protect the urb from being unanchored
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* twice, only the winner of the race gets the job.
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*/
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if (likely(anchor == urb->anchor))
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__usb_unanchor_urb(urb, anchor);
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spin_unlock_irqrestore(&anchor->lock, flags);
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}
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EXPORT_SYMBOL_GPL(usb_unanchor_urb);
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/*-------------------------------------------------------------------*/
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/**
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* usb_submit_urb - issue an asynchronous transfer request for an endpoint
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* @urb: pointer to the urb describing the request
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* @mem_flags: the type of memory to allocate, see kmalloc() for a list
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* of valid options for this.
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*
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* This submits a transfer request, and transfers control of the URB
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* describing that request to the USB subsystem. Request completion will
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* be indicated later, asynchronously, by calling the completion handler.
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* The three types of completion are success, error, and unlink
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* (a software-induced fault, also called "request cancellation").
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*
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* URBs may be submitted in interrupt context.
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*
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* The caller must have correctly initialized the URB before submitting
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* it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
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* available to ensure that most fields are correctly initialized, for
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* the particular kind of transfer, although they will not initialize
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* any transfer flags.
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*
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* Successful submissions return 0; otherwise this routine returns a
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* negative error number. If the submission is successful, the complete()
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* callback from the URB will be called exactly once, when the USB core and
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* Host Controller Driver (HCD) are finished with the URB. When the completion
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* function is called, control of the URB is returned to the device
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* driver which issued the request. The completion handler may then
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* immediately free or reuse that URB.
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*
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* With few exceptions, USB device drivers should never access URB fields
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* provided by usbcore or the HCD until its complete() is called.
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* The exceptions relate to periodic transfer scheduling. For both
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* interrupt and isochronous urbs, as part of successful URB submission
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* urb->interval is modified to reflect the actual transfer period used
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* (normally some power of two units). And for isochronous urbs,
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* urb->start_frame is modified to reflect when the URB's transfers were
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* scheduled to start. Not all isochronous transfer scheduling policies
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* will work, but most host controller drivers should easily handle ISO
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* queues going from now until 10-200 msec into the future.
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*
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* For control endpoints, the synchronous usb_control_msg() call is
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* often used (in non-interrupt context) instead of this call.
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* That is often used through convenience wrappers, for the requests
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* that are standardized in the USB 2.0 specification. For bulk
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* endpoints, a synchronous usb_bulk_msg() call is available.
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*
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* Request Queuing:
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*
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* URBs may be submitted to endpoints before previous ones complete, to
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* minimize the impact of interrupt latencies and system overhead on data
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* throughput. With that queuing policy, an endpoint's queue would never
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* be empty. This is required for continuous isochronous data streams,
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* and may also be required for some kinds of interrupt transfers. Such
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* queuing also maximizes bandwidth utilization by letting USB controllers
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* start work on later requests before driver software has finished the
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* completion processing for earlier (successful) requests.
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*
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* As of Linux 2.6, all USB endpoint transfer queues support depths greater
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* than one. This was previously a HCD-specific behavior, except for ISO
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* transfers. Non-isochronous endpoint queues are inactive during cleanup
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* after faults (transfer errors or cancellation).
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*
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* Reserved Bandwidth Transfers:
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*
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* Periodic transfers (interrupt or isochronous) are performed repeatedly,
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* using the interval specified in the urb. Submitting the first urb to
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* the endpoint reserves the bandwidth necessary to make those transfers.
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* If the USB subsystem can't allocate sufficient bandwidth to perform
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* the periodic request, submitting such a periodic request should fail.
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*
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* For devices under xHCI, the bandwidth is reserved at configuration time, or
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* when the alt setting is selected. If there is not enough bus bandwidth, the
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* configuration/alt setting request will fail. Therefore, submissions to
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* periodic endpoints on devices under xHCI should never fail due to bandwidth
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* constraints.
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*
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* Device drivers must explicitly request that repetition, by ensuring that
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* some URB is always on the endpoint's queue (except possibly for short
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* periods during completion callacks). When there is no longer an urb
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* queued, the endpoint's bandwidth reservation is canceled. This means
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* drivers can use their completion handlers to ensure they keep bandwidth
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* they need, by reinitializing and resubmitting the just-completed urb
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* until the driver longer needs that periodic bandwidth.
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*
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* Memory Flags:
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*
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* The general rules for how to decide which mem_flags to use
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* are the same as for kmalloc. There are four
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* different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
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* GFP_ATOMIC.
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*
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* GFP_NOFS is not ever used, as it has not been implemented yet.
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*
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* GFP_ATOMIC is used when
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* (a) you are inside a completion handler, an interrupt, bottom half,
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* tasklet or timer, or
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* (b) you are holding a spinlock or rwlock (does not apply to
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* semaphores), or
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* (c) current->state != TASK_RUNNING, this is the case only after
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* you've changed it.
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*
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* GFP_NOIO is used in the block io path and error handling of storage
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* devices.
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*
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* All other situations use GFP_KERNEL.
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*
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* Some more specific rules for mem_flags can be inferred, such as
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* (1) start_xmit, timeout, and receive methods of network drivers must
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* use GFP_ATOMIC (they are called with a spinlock held);
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* (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
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* called with a spinlock held);
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* (3) If you use a kernel thread with a network driver you must use
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* GFP_NOIO, unless (b) or (c) apply;
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* (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
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* apply or your are in a storage driver's block io path;
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* (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
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* (6) changing firmware on a running storage or net device uses
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* GFP_NOIO, unless b) or c) apply
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*
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*/
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int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
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{
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int xfertype, max;
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struct usb_device *dev;
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struct usb_host_endpoint *ep;
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int is_out;
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if (!urb || urb->hcpriv || !urb->complete)
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return -EINVAL;
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dev = urb->dev;
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if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
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return -ENODEV;
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/* For now, get the endpoint from the pipe. Eventually drivers
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* will be required to set urb->ep directly and we will eliminate
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* urb->pipe.
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*/
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ep = usb_pipe_endpoint(dev, urb->pipe);
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if (!ep)
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return -ENOENT;
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urb->ep = ep;
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urb->status = -EINPROGRESS;
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urb->actual_length = 0;
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/* Lots of sanity checks, so HCDs can rely on clean data
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* and don't need to duplicate tests
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*/
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xfertype = usb_endpoint_type(&ep->desc);
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if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
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struct usb_ctrlrequest *setup =
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(struct usb_ctrlrequest *) urb->setup_packet;
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if (!setup)
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return -ENOEXEC;
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is_out = !(setup->bRequestType & USB_DIR_IN) ||
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!setup->wLength;
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} else {
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is_out = usb_endpoint_dir_out(&ep->desc);
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}
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/* Clear the internal flags and cache the direction for later use */
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urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
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URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
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URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
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URB_DMA_SG_COMBINED);
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urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);
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if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
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dev->state < USB_STATE_CONFIGURED)
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return -ENODEV;
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max = usb_endpoint_maxp(&ep->desc);
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if (max <= 0) {
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dev_dbg(&dev->dev,
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"bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
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usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
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__func__, max);
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return -EMSGSIZE;
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}
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/* periodic transfers limit size per frame/uframe,
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* but drivers only control those sizes for ISO.
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* while we're checking, initialize return status.
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*/
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if (xfertype == USB_ENDPOINT_XFER_ISOC) {
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int n, len;
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/* SuperSpeed isoc endpoints have up to 16 bursts of up to
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* 3 packets each
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*/
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if (dev->speed == USB_SPEED_SUPER) {
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int burst = 1 + ep->ss_ep_comp.bMaxBurst;
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int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
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max *= burst;
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max *= mult;
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}
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/* "high bandwidth" mode, 1-3 packets/uframe? */
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if (dev->speed == USB_SPEED_HIGH) {
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int mult = 1 + ((max >> 11) & 0x03);
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max &= 0x07ff;
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max *= mult;
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}
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if (urb->number_of_packets <= 0)
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return -EINVAL;
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for (n = 0; n < urb->number_of_packets; n++) {
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len = urb->iso_frame_desc[n].length;
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if (len < 0 || len > max)
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return -EMSGSIZE;
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urb->iso_frame_desc[n].status = -EXDEV;
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urb->iso_frame_desc[n].actual_length = 0;
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}
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}
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/* the I/O buffer must be mapped/unmapped, except when length=0 */
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if (urb->transfer_buffer_length > INT_MAX)
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return -EMSGSIZE;
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#ifdef DEBUG
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/* stuff that drivers shouldn't do, but which shouldn't
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* cause problems in HCDs if they get it wrong.
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*/
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{
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unsigned int allowed;
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static int pipetypes[4] = {
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PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
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};
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/* Check that the pipe's type matches the endpoint's type */
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if (usb_pipetype(urb->pipe) != pipetypes[xfertype])
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dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
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usb_pipetype(urb->pipe), pipetypes[xfertype]);
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/* Check against a simple/standard policy */
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allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK |
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URB_FREE_BUFFER);
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switch (xfertype) {
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case USB_ENDPOINT_XFER_BULK:
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if (is_out)
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allowed |= URB_ZERO_PACKET;
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/* FALLTHROUGH */
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case USB_ENDPOINT_XFER_CONTROL:
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allowed |= URB_NO_FSBR; /* only affects UHCI */
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/* FALLTHROUGH */
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default: /* all non-iso endpoints */
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if (!is_out)
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allowed |= URB_SHORT_NOT_OK;
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break;
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case USB_ENDPOINT_XFER_ISOC:
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allowed |= URB_ISO_ASAP;
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break;
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}
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allowed &= urb->transfer_flags;
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/* warn if submitter gave bogus flags */
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if (allowed != urb->transfer_flags)
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dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n",
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urb->transfer_flags, allowed);
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}
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#endif
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/*
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* Force periodic transfer intervals to be legal values that are
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* a power of two (so HCDs don't need to).
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*
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* FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
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* supports different values... this uses EHCI/UHCI defaults (and
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* EHCI can use smaller non-default values).
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*/
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switch (xfertype) {
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case USB_ENDPOINT_XFER_ISOC:
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case USB_ENDPOINT_XFER_INT:
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/* too small? */
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switch (dev->speed) {
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case USB_SPEED_WIRELESS:
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if (urb->interval < 6)
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return -EINVAL;
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break;
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default:
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if (urb->interval <= 0)
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return -EINVAL;
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break;
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}
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/* too big? */
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switch (dev->speed) {
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case USB_SPEED_SUPER: /* units are 125us */
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/* Handle up to 2^(16-1) microframes */
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if (urb->interval > (1 << 15))
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return -EINVAL;
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max = 1 << 15;
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break;
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|
case USB_SPEED_WIRELESS:
|
|
if (urb->interval > 16)
|
|
return -EINVAL;
|
|
break;
|
|
case USB_SPEED_HIGH: /* units are microframes */
|
|
/* NOTE usb handles 2^15 */
|
|
if (urb->interval > (1024 * 8))
|
|
urb->interval = 1024 * 8;
|
|
max = 1024 * 8;
|
|
break;
|
|
case USB_SPEED_FULL: /* units are frames/msec */
|
|
case USB_SPEED_LOW:
|
|
if (xfertype == USB_ENDPOINT_XFER_INT) {
|
|
if (urb->interval > 255)
|
|
return -EINVAL;
|
|
/* NOTE ohci only handles up to 32 */
|
|
max = 128;
|
|
} else {
|
|
if (urb->interval > 1024)
|
|
urb->interval = 1024;
|
|
/* NOTE usb and ohci handle up to 2^15 */
|
|
max = 1024;
|
|
}
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
if (dev->speed != USB_SPEED_WIRELESS) {
|
|
/* Round down to a power of 2, no more than max */
|
|
urb->interval = min(max, 1 << ilog2(urb->interval));
|
|
}
|
|
}
|
|
|
|
return usb_hcd_submit_urb(urb, mem_flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_submit_urb);
|
|
|
|
/*-------------------------------------------------------------------*/
|
|
|
|
/**
|
|
* usb_unlink_urb - abort/cancel a transfer request for an endpoint
|
|
* @urb: pointer to urb describing a previously submitted request,
|
|
* may be NULL
|
|
*
|
|
* This routine cancels an in-progress request. URBs complete only once
|
|
* per submission, and may be canceled only once per submission.
|
|
* Successful cancellation means termination of @urb will be expedited
|
|
* and the completion handler will be called with a status code
|
|
* indicating that the request has been canceled (rather than any other
|
|
* code).
|
|
*
|
|
* Drivers should not call this routine or related routines, such as
|
|
* usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
|
|
* method has returned. The disconnect function should synchronize with
|
|
* a driver's I/O routines to insure that all URB-related activity has
|
|
* completed before it returns.
|
|
*
|
|
* This request is asynchronous, however the HCD might call the ->complete()
|
|
* callback during unlink. Therefore when drivers call usb_unlink_urb(), they
|
|
* must not hold any locks that may be taken by the completion function.
|
|
* Success is indicated by returning -EINPROGRESS, at which time the URB will
|
|
* probably not yet have been given back to the device driver. When it is
|
|
* eventually called, the completion function will see @urb->status ==
|
|
* -ECONNRESET.
|
|
* Failure is indicated by usb_unlink_urb() returning any other value.
|
|
* Unlinking will fail when @urb is not currently "linked" (i.e., it was
|
|
* never submitted, or it was unlinked before, or the hardware is already
|
|
* finished with it), even if the completion handler has not yet run.
|
|
*
|
|
* The URB must not be deallocated while this routine is running. In
|
|
* particular, when a driver calls this routine, it must insure that the
|
|
* completion handler cannot deallocate the URB.
|
|
*
|
|
* Unlinking and Endpoint Queues:
|
|
*
|
|
* [The behaviors and guarantees described below do not apply to virtual
|
|
* root hubs but only to endpoint queues for physical USB devices.]
|
|
*
|
|
* Host Controller Drivers (HCDs) place all the URBs for a particular
|
|
* endpoint in a queue. Normally the queue advances as the controller
|
|
* hardware processes each request. But when an URB terminates with an
|
|
* error its queue generally stops (see below), at least until that URB's
|
|
* completion routine returns. It is guaranteed that a stopped queue
|
|
* will not restart until all its unlinked URBs have been fully retired,
|
|
* with their completion routines run, even if that's not until some time
|
|
* after the original completion handler returns. The same behavior and
|
|
* guarantee apply when an URB terminates because it was unlinked.
|
|
*
|
|
* Bulk and interrupt endpoint queues are guaranteed to stop whenever an
|
|
* URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
|
|
* and -EREMOTEIO. Control endpoint queues behave the same way except
|
|
* that they are not guaranteed to stop for -EREMOTEIO errors. Queues
|
|
* for isochronous endpoints are treated differently, because they must
|
|
* advance at fixed rates. Such queues do not stop when an URB
|
|
* encounters an error or is unlinked. An unlinked isochronous URB may
|
|
* leave a gap in the stream of packets; it is undefined whether such
|
|
* gaps can be filled in.
|
|
*
|
|
* Note that early termination of an URB because a short packet was
|
|
* received will generate a -EREMOTEIO error if and only if the
|
|
* URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
|
|
* drivers can build deep queues for large or complex bulk transfers
|
|
* and clean them up reliably after any sort of aborted transfer by
|
|
* unlinking all pending URBs at the first fault.
|
|
*
|
|
* When a control URB terminates with an error other than -EREMOTEIO, it
|
|
* is quite likely that the status stage of the transfer will not take
|
|
* place.
|
|
*/
|
|
int usb_unlink_urb(struct urb *urb)
|
|
{
|
|
if (!urb)
|
|
return -EINVAL;
|
|
if (!urb->dev)
|
|
return -ENODEV;
|
|
if (!urb->ep)
|
|
return -EIDRM;
|
|
return usb_hcd_unlink_urb(urb, -ECONNRESET);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_unlink_urb);
|
|
|
|
/**
|
|
* usb_kill_urb - cancel a transfer request and wait for it to finish
|
|
* @urb: pointer to URB describing a previously submitted request,
|
|
* may be NULL
|
|
*
|
|
* This routine cancels an in-progress request. It is guaranteed that
|
|
* upon return all completion handlers will have finished and the URB
|
|
* will be totally idle and available for reuse. These features make
|
|
* this an ideal way to stop I/O in a disconnect() callback or close()
|
|
* function. If the request has not already finished or been unlinked
|
|
* the completion handler will see urb->status == -ENOENT.
|
|
*
|
|
* While the routine is running, attempts to resubmit the URB will fail
|
|
* with error -EPERM. Thus even if the URB's completion handler always
|
|
* tries to resubmit, it will not succeed and the URB will become idle.
|
|
*
|
|
* The URB must not be deallocated while this routine is running. In
|
|
* particular, when a driver calls this routine, it must insure that the
|
|
* completion handler cannot deallocate the URB.
|
|
*
|
|
* This routine may not be used in an interrupt context (such as a bottom
|
|
* half or a completion handler), or when holding a spinlock, or in other
|
|
* situations where the caller can't schedule().
|
|
*
|
|
* This routine should not be called by a driver after its disconnect
|
|
* method has returned.
|
|
*/
|
|
void usb_kill_urb(struct urb *urb)
|
|
{
|
|
might_sleep();
|
|
if (!(urb && urb->dev && urb->ep))
|
|
return;
|
|
atomic_inc(&urb->reject);
|
|
|
|
usb_hcd_unlink_urb(urb, -ENOENT);
|
|
wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
|
|
|
|
atomic_dec(&urb->reject);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_kill_urb);
|
|
|
|
/**
|
|
* usb_poison_urb - reliably kill a transfer and prevent further use of an URB
|
|
* @urb: pointer to URB describing a previously submitted request,
|
|
* may be NULL
|
|
*
|
|
* This routine cancels an in-progress request. It is guaranteed that
|
|
* upon return all completion handlers will have finished and the URB
|
|
* will be totally idle and cannot be reused. These features make
|
|
* this an ideal way to stop I/O in a disconnect() callback.
|
|
* If the request has not already finished or been unlinked
|
|
* the completion handler will see urb->status == -ENOENT.
|
|
*
|
|
* After and while the routine runs, attempts to resubmit the URB will fail
|
|
* with error -EPERM. Thus even if the URB's completion handler always
|
|
* tries to resubmit, it will not succeed and the URB will become idle.
|
|
*
|
|
* The URB must not be deallocated while this routine is running. In
|
|
* particular, when a driver calls this routine, it must insure that the
|
|
* completion handler cannot deallocate the URB.
|
|
*
|
|
* This routine may not be used in an interrupt context (such as a bottom
|
|
* half or a completion handler), or when holding a spinlock, or in other
|
|
* situations where the caller can't schedule().
|
|
*
|
|
* This routine should not be called by a driver after its disconnect
|
|
* method has returned.
|
|
*/
|
|
void usb_poison_urb(struct urb *urb)
|
|
{
|
|
might_sleep();
|
|
if (!(urb && urb->dev && urb->ep))
|
|
return;
|
|
atomic_inc(&urb->reject);
|
|
|
|
usb_hcd_unlink_urb(urb, -ENOENT);
|
|
wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_poison_urb);
|
|
|
|
void usb_unpoison_urb(struct urb *urb)
|
|
{
|
|
if (!urb)
|
|
return;
|
|
|
|
atomic_dec(&urb->reject);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_unpoison_urb);
|
|
|
|
/**
|
|
* usb_block_urb - reliably prevent further use of an URB
|
|
* @urb: pointer to URB to be blocked, may be NULL
|
|
*
|
|
* After the routine has run, attempts to resubmit the URB will fail
|
|
* with error -EPERM. Thus even if the URB's completion handler always
|
|
* tries to resubmit, it will not succeed and the URB will become idle.
|
|
*
|
|
* The URB must not be deallocated while this routine is running. In
|
|
* particular, when a driver calls this routine, it must insure that the
|
|
* completion handler cannot deallocate the URB.
|
|
*/
|
|
void usb_block_urb(struct urb *urb)
|
|
{
|
|
if (!urb)
|
|
return;
|
|
|
|
atomic_inc(&urb->reject);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_block_urb);
|
|
|
|
/**
|
|
* usb_kill_anchored_urbs - cancel transfer requests en masse
|
|
* @anchor: anchor the requests are bound to
|
|
*
|
|
* this allows all outstanding URBs to be killed starting
|
|
* from the back of the queue
|
|
*
|
|
* This routine should not be called by a driver after its disconnect
|
|
* method has returned.
|
|
*/
|
|
void usb_kill_anchored_urbs(struct usb_anchor *anchor)
|
|
{
|
|
struct urb *victim;
|
|
|
|
spin_lock_irq(&anchor->lock);
|
|
while (!list_empty(&anchor->urb_list)) {
|
|
victim = list_entry(anchor->urb_list.prev, struct urb,
|
|
anchor_list);
|
|
/* we must make sure the URB isn't freed before we kill it*/
|
|
usb_get_urb(victim);
|
|
spin_unlock_irq(&anchor->lock);
|
|
/* this will unanchor the URB */
|
|
usb_kill_urb(victim);
|
|
usb_put_urb(victim);
|
|
spin_lock_irq(&anchor->lock);
|
|
}
|
|
spin_unlock_irq(&anchor->lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
|
|
|
|
|
|
/**
|
|
* usb_poison_anchored_urbs - cease all traffic from an anchor
|
|
* @anchor: anchor the requests are bound to
|
|
*
|
|
* this allows all outstanding URBs to be poisoned starting
|
|
* from the back of the queue. Newly added URBs will also be
|
|
* poisoned
|
|
*
|
|
* This routine should not be called by a driver after its disconnect
|
|
* method has returned.
|
|
*/
|
|
void usb_poison_anchored_urbs(struct usb_anchor *anchor)
|
|
{
|
|
struct urb *victim;
|
|
|
|
spin_lock_irq(&anchor->lock);
|
|
anchor->poisoned = 1;
|
|
while (!list_empty(&anchor->urb_list)) {
|
|
victim = list_entry(anchor->urb_list.prev, struct urb,
|
|
anchor_list);
|
|
/* we must make sure the URB isn't freed before we kill it*/
|
|
usb_get_urb(victim);
|
|
spin_unlock_irq(&anchor->lock);
|
|
/* this will unanchor the URB */
|
|
usb_poison_urb(victim);
|
|
usb_put_urb(victim);
|
|
spin_lock_irq(&anchor->lock);
|
|
}
|
|
spin_unlock_irq(&anchor->lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs);
|
|
|
|
/**
|
|
* usb_unpoison_anchored_urbs - let an anchor be used successfully again
|
|
* @anchor: anchor the requests are bound to
|
|
*
|
|
* Reverses the effect of usb_poison_anchored_urbs
|
|
* the anchor can be used normally after it returns
|
|
*/
|
|
void usb_unpoison_anchored_urbs(struct usb_anchor *anchor)
|
|
{
|
|
unsigned long flags;
|
|
struct urb *lazarus;
|
|
|
|
spin_lock_irqsave(&anchor->lock, flags);
|
|
list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) {
|
|
usb_unpoison_urb(lazarus);
|
|
}
|
|
anchor->poisoned = 0;
|
|
spin_unlock_irqrestore(&anchor->lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs);
|
|
/**
|
|
* usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
|
|
* @anchor: anchor the requests are bound to
|
|
*
|
|
* this allows all outstanding URBs to be unlinked starting
|
|
* from the back of the queue. This function is asynchronous.
|
|
* The unlinking is just tiggered. It may happen after this
|
|
* function has returned.
|
|
*
|
|
* This routine should not be called by a driver after its disconnect
|
|
* method has returned.
|
|
*/
|
|
void usb_unlink_anchored_urbs(struct usb_anchor *anchor)
|
|
{
|
|
struct urb *victim;
|
|
|
|
while ((victim = usb_get_from_anchor(anchor)) != NULL) {
|
|
usb_unlink_urb(victim);
|
|
usb_put_urb(victim);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs);
|
|
|
|
/**
|
|
* usb_wait_anchor_empty_timeout - wait for an anchor to be unused
|
|
* @anchor: the anchor you want to become unused
|
|
* @timeout: how long you are willing to wait in milliseconds
|
|
*
|
|
* Call this is you want to be sure all an anchor's
|
|
* URBs have finished
|
|
*/
|
|
int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
|
|
unsigned int timeout)
|
|
{
|
|
return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list),
|
|
msecs_to_jiffies(timeout));
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
|
|
|
|
/**
|
|
* usb_get_from_anchor - get an anchor's oldest urb
|
|
* @anchor: the anchor whose urb you want
|
|
*
|
|
* this will take the oldest urb from an anchor,
|
|
* unanchor and return it
|
|
*/
|
|
struct urb *usb_get_from_anchor(struct usb_anchor *anchor)
|
|
{
|
|
struct urb *victim;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&anchor->lock, flags);
|
|
if (!list_empty(&anchor->urb_list)) {
|
|
victim = list_entry(anchor->urb_list.next, struct urb,
|
|
anchor_list);
|
|
usb_get_urb(victim);
|
|
__usb_unanchor_urb(victim, anchor);
|
|
} else {
|
|
victim = NULL;
|
|
}
|
|
spin_unlock_irqrestore(&anchor->lock, flags);
|
|
|
|
return victim;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(usb_get_from_anchor);
|
|
|
|
/**
|
|
* usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
|
|
* @anchor: the anchor whose urbs you want to unanchor
|
|
*
|
|
* use this to get rid of all an anchor's urbs
|
|
*/
|
|
void usb_scuttle_anchored_urbs(struct usb_anchor *anchor)
|
|
{
|
|
struct urb *victim;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&anchor->lock, flags);
|
|
while (!list_empty(&anchor->urb_list)) {
|
|
victim = list_entry(anchor->urb_list.prev, struct urb,
|
|
anchor_list);
|
|
__usb_unanchor_urb(victim, anchor);
|
|
}
|
|
spin_unlock_irqrestore(&anchor->lock, flags);
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs);
|
|
|
|
/**
|
|
* usb_anchor_empty - is an anchor empty
|
|
* @anchor: the anchor you want to query
|
|
*
|
|
* returns 1 if the anchor has no urbs associated with it
|
|
*/
|
|
int usb_anchor_empty(struct usb_anchor *anchor)
|
|
{
|
|
return list_empty(&anchor->urb_list);
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(usb_anchor_empty);
|
|
|