From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Balbi 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> References: <1562324238-16655-1-git-send-email-pawell@cadence.com> <1562324238-16655-6-git-send-email-pawell@cadence.com> <877e8tm25r.fsf@linux.intel.com> <8736idnu0q.fsf@gmail.com> <87k1bjvtvi.fsf@gmail.com> <87imr2u77c.fsf@gmail.com> <87d0hau37p.fsf@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Pawel Laszczak , "devicetree@vger.kernel.org" , Alan Stern Cc: "gregkh@linuxfoundation.org" , "linux-usb@vger.kernel.org" , "hdegoede@redhat.com" , "heikki.krogerus@linux.intel.com" , "robh+dt@kernel.org" , "rogerq@ti.com" , "linux-kernel@vger.kernel.org" , "jbergsagel@ti.com" , "nsekhar@ti.com" , "nm@ti.com" , Suresh Punnoose , "peter.chen@nxp.com" , Jayshri Dajiram Pawar , Rahul Kumar List-Id: devicetree@vger.kernel.org --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, Pawel Laszczak 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.=20 > > Here you have a fragment of complaints:=20 > [ 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): [] _ra= w_spin_unlock_irq+0x2c/0x40 > [ 7420.503070] hardirqs last disabled at (2962): [] _ra= w_spin_lock_irqsave+0x25/0x60 > [ 7420.503074] softirqs last enabled at (2918): [] __d= o_softirq+0x340/0x451 > [ 7420.503079] softirqs last disabled at (2657): [] irq= _exit+0xc6/0xd0 > [ 7420.503082] ---[ end trace d02652af11011c3b ]--- > > Maybe it's a bug in implementation of this function. I allocate memory w= ith flag GFP_ATOMIC with=20 > disabled interrupt, but I can't free such memory.=20 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 =3D 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? =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEElLzh7wn96CXwjh2IzL64meEamQYFAl1RQLsACgkQzL64meEa mQaIQRAA0TD8TKQptnOmAGv1zIYC6xgBgnsm0x2vGb6xL4PRP2OCZ5rtKxQ68m4V yp7zk5HSsVupbVXXvnlrwW1kkYSeSGy6Eu4R13SndS1AzDhoT4GXVQp4p4lnC/qP C7tHOOEFBAcN6/R5xmdfztd7OnNzvLVSyHQDjPTV/ZrhO5WA/7PiISDbrIJwko63 ew2eR97yc6ieP0AntOPEePHqp07h2PkOSDBECZd3k4HqI2HhZI/yRK2x02dzYLTd UeKfQePHjlfyhoptUrsumaombaIvOi4OzaW+e/XXitZAzcQhlbjiKtBy8HzSiF0U 4Y1ElXeeP1HqQBmWvOetFSgKLNjR5TAlRrWOp/x6XS8IUM/jyJHKIYqMWShjGbPZ /V2JvOhJH8z7/Gnldx47LC4qyHQaNFhtZ8DTvGTLyYiC4aJp1geNvOsn7h4hmUNp Un5t5ytPUuNrWITTN4V6w1S8eQem1GN947GTJmWDICYrlKWuBwAIfM7GrVgV0omp 4YGouah8LD8o+h2IVHqAlRui/uNQMxk0h+MHHkxo8JbrFJfOdR2JBKUT36Npv4ut 3KaCHAVG/LHY5+2LbqlbLZiH9gUjntSs0efbDDePT4OudMFqz3HX95MHAcNq1JgP s4NR1rdSKILE+EYOk9XT6ch5jNKqq9ylfwCuRhJtIShcyBGEHF0= =xDrg -----END PGP SIGNATURE----- --=-=-=--