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From: Felipe Balbi <felipe.balbi@linux.intel.com>
To: Pawel Laszczak <pawell@cadence.com>,
	"devicetree\@vger.kernel.org" <devicetree@vger.kernel.org>,
	Alan Stern <stern@rowland.harvard.edu>
Cc: "gregkh\@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"linux-usb\@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"hdegoede\@redhat.com" <hdegoede@redhat.com>,
	"heikki.krogerus\@linux.intel.com"
	<heikki.krogerus@linux.intel.com>,
	"robh+dt\@kernel.org" <robh+dt@kernel.org>,
	"rogerq\@ti.com" <rogerq@ti.com>,
	"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"jbergsagel\@ti.com" <jbergsagel@ti.com>,
	"nsekhar\@ti.com" <nsekhar@ti.com>, "nm\@ti.com" <nm@ti.com>,
	Suresh Punnoose <sureshp@cadence.com>,
	"peter.chen\@nxp.com" <peter.chen@nxp.com>,
	Jayshri Dajiram Pawar <jpawar@cadence.com>,
	Rahul Kumar <kurahul@cadence.com>
Subject: RE: [PATCH v9 5/6] usb:cdns3 Add Cadence USB3 DRD Driver
Date: Mon, 12 Aug 2019 13:34:35 +0300
Message-ID: <877e7iu0xw.fsf@gmail.com> (raw)
In-Reply-To: <BYAPR07MB470931F8C699784CC88E21CBDDD30@BYAPR07MB4709.namprd07.prod.outlook.com>

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Hi,

Pawel Laszczak <pawell@cadence.com> writes:
>>>>Yet another thread? Can't you just run this right before giving back the
>>>>USB request? So, don't do it from IRQ handler, but from giveback path?
>>>
>>> Do you mean in:
>>> 	if (request->complete) {
>>> 		spin_unlock(&priv_dev->lock);
>>> 		if (priv_dev->run_garbage_collector) {
>>> 			....
>>> 		}
>>> 		usb_gadget_giveback_request(&priv_ep->endpoint,
>>> 					    request);
>>> 		spin_lock(&priv_dev->lock);
>>> 	}
>>> ??
>>
>>right, you can do it right before giving back the request. Or right
>>after.
>>
>>> I ask because this is finally also called from IRQ handler:
>>>
>>> cdns3_device_thread_irq_handler
>>>     -> cdns3_check_ep_interrupt_proceed
>>>         -> cdns3_transfer_completed
>>>             -> cdns3_gadget_giveback
>>>                 -> usb_gadget_giveback_request
>>
>>Did you notice that it doesn't reenable interrupts, though?
>
> I noticed that there is a lack of reenabling interrupts :)
>
> The problem is that If I have disabled interrupt the kernel complains
> for using dma_free_coherent function in such place. 
>
> Here you have a fragment of complaints: 
> [ 7420.502863] WARNING: CPU: 0 PID: 10260 at kernel/dma/mapping.c:281 dma_free_attrs+0xa0/0xd0
> [ 7420.502866] Modules linked in: usb_f_mass_storage cdns3(OE) cdns3_pci_wrap(OE) libcomposite
> 		...
> [ 7420.502965]  cdns3_gadget_giveback+0x159/0x2a0 [cdns3]
> [ 7420.502975]  cdns3_transfer_completed+0xc5/0x3c0 [cdns3]
> [ 7420.502986]  cdns3_device_thread_irq_handler+0x1b1/0xab0 [cdns3]
> [ 7420.502991]  ? __schedule+0x333/0x7e0
> [ 7420.503001]  irq_thread_fn+0x26/0x60
> [ 7420.503006]  ? irq_thread+0xa8/0x1b0
> [ 7420.503011]  irq_thread+0x10e/0x1b0
> [ 7420.503015]  ? irq_forced_thread_fn+0x80/0x80
> [ 7420.503021]  ? wake_threads_waitq+0x30/0x30
> [ 7420.503029]  kthread+0x12c/0x150
> [ 7420.503034]  ? irq_thread_check_affinity+0xe0/0xe0
> [ 7420.503038]  ? kthread_park+0x90/0x90
> [ 7420.503045]  ret_from_fork+0x3a/0x50
> [ 7420.503061] irq event stamp: 2962
> [ 7420.503065] hardirqs last  enabled at (2961): [<ffffffffb252672c>] _raw_spin_unlock_irq+0x2c/0x40
> [ 7420.503070] hardirqs last disabled at (2962): [<ffffffffb25268f5>] _raw_spin_lock_irqsave+0x25/0x60
> [ 7420.503074] softirqs last  enabled at (2918): [<ffffffffb2800340>] __do_softirq+0x340/0x451
> [ 7420.503079] softirqs last disabled at (2657): [<ffffffffb1aa02b6>] irq_exit+0xc6/0xd0
> [ 7420.503082] ---[ end trace d02652af11011c3b ]---
>
> Maybe it's a bug in implementation of this function.  I allocate memory with flag GFP_ATOMIC with 
> disabled interrupt, but I can't free such memory. 

I don't understand the intricacies of the coherent API to judge if it's
a bug in the API itself. In any case, here's where the splat comes from:

void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
		dma_addr_t dma_handle, unsigned long attrs)
{
	const struct dma_map_ops *ops = get_dma_ops(dev);

	if (dma_release_from_dev_coherent(dev, get_order(size), cpu_addr))
		return;
	/*
	 * On non-coherent platforms which implement DMA-coherent buffers via
	 * non-cacheable remaps, ops->free() may call vunmap(). Thus getting
	 * this far in IRQ context is a) at risk of a BUG_ON() or trying to
	 * sleep on some machines, and b) an indication that the driver is
	 * probably misusing the coherent API anyway.
	 */
	WARN_ON(irqs_disabled());

	if (!cpu_addr)
		return;

	debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
	if (dma_is_direct(ops))
		dma_direct_free(dev, size, cpu_addr, dma_handle, attrs);
	else if (ops->free)
		ops->free(dev, size, cpu_addr, dma_handle, attrs);
}
EXPORT_SYMBOL(dma_free_attrs);

maybe you're gonna have to fire up a workqueue to free this memory for
you :-(

Unless someone else has better ideas. Alan, Greg, any ideas?

-- 
balbi

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  reply index

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-05 10:57 [PATCH v9 0/6] Introduced new Cadence USBSS " Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 1/6] dt-bindings: add binding for USBSS-DRD controller Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 2/6] usb:gadget Separated decoding functions from dwc3 driver Pawel Laszczak
2019-07-05 11:27   ` Greg KH
2019-07-05 11:39     ` Pawel Laszczak
2019-07-05 11:49       ` Greg KH
2019-07-05 12:03         ` Pawel Laszczak
2019-07-05 11:39   ` Felipe Balbi
2019-07-05 11:44     ` Pawel Laszczak
2019-08-07 10:17       ` Roger Quadros
2019-08-07 10:22         ` Felipe Balbi
2019-08-08  3:07           ` Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 3/6] usb:gadget Patch simplify usb_decode_set_clear_feature function Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 4/6] usb:gadget Simplify usb_decode_get_set_descriptor function Pawel Laszczak
2019-07-05 10:57 ` [PATCH v9 5/6] usb:cdns3 Add Cadence USB3 DRD Driver Pawel Laszczak
2019-07-05 11:55   ` Felipe Balbi
2019-07-07 17:56     ` Pawel Laszczak
2019-07-08  6:29       ` Felipe Balbi
2019-07-08 10:59         ` Pawel Laszczak
2019-07-08 11:15           ` Felipe Balbi
2019-07-08 11:45             ` Pawel Laszczak
2019-07-08 11:59               ` Felipe Balbi
2019-07-08 12:39                 ` Pawel Laszczak
2019-07-09  4:23         ` Pawel Laszczak
2019-07-09  6:36           ` Felipe Balbi
2019-07-09  7:07             ` Pawel Laszczak
2019-07-09  7:22               ` Felipe Balbi
2019-07-09  7:29                 ` Pawel Laszczak
2019-07-10  8:25       ` Pawel Laszczak
2019-07-08  7:11   ` Felipe Balbi
2019-07-15 11:00     ` Pawel Laszczak
2019-08-07 10:34       ` Felipe Balbi
2019-08-10 20:39         ` Pawel Laszczak
2019-08-12  1:55           ` Peter Chen
2019-08-12  4:43             ` Pawel Laszczak
2019-08-12  5:24           ` Felipe Balbi
2019-08-12  7:13             ` Pawel Laszczak
2019-08-12  8:19               ` Felipe Balbi
2019-08-12  9:13                 ` Pawel Laszczak
2019-08-12  9:45                   ` Felipe Balbi
2019-08-12 10:26                     ` Pawel Laszczak
2019-08-12 10:34                       ` Felipe Balbi [this message]
2019-08-12 14:20                         ` Alan Stern
2019-07-05 10:57 ` [PATCH v9 6/6] usb:cdns3 Fix for stuck packets in on-chip OUT buffer Pawel Laszczak

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