/* * Ingenic JZ4740 "glue layer" * * Copyright (C) 2013, Apelete Seketeli * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include #include #include #include "musb_core.h" struct jz4740_glue { struct device *dev; struct platform_device *musb; struct clk *clk; }; static irqreturn_t jz4740_musb_interrupt(int irq, void *__hci) { unsigned long flags; irqreturn_t retval = IRQ_NONE; struct musb *musb = __hci; spin_lock_irqsave(&musb->lock, flags); musb->int_usb = musb_readb(musb->mregs, MUSB_INTRUSB); musb->int_tx = musb_readw(musb->mregs, MUSB_INTRTX); musb->int_rx = musb_readw(musb->mregs, MUSB_INTRRX); /* * The controller is gadget only, the state of the host mode IRQ bits is * undefined. Mask them to make sure that the musb driver core will * never see them set */ musb->int_usb &= MUSB_INTR_SUSPEND | MUSB_INTR_RESUME | MUSB_INTR_RESET | MUSB_INTR_SOF; if (musb->int_usb || musb->int_tx || musb->int_rx) retval = musb_interrupt(musb); spin_unlock_irqrestore(&musb->lock, flags); return retval; } static struct musb_fifo_cfg jz4740_musb_fifo_cfg[] = { { .hw_ep_num = 1, .style = FIFO_TX, .maxpacket = 512, }, { .hw_ep_num = 1, .style = FIFO_RX, .maxpacket = 512, }, { .hw_ep_num = 2, .style = FIFO_TX, .maxpacket = 64, }, }; static struct musb_hdrc_config jz4740_musb_config = { /* Silicon does not implement USB OTG. */ .multipoint = 0, /* Max EPs scanned, driver will decide which EP can be used. */ .num_eps = 4, /* RAMbits needed to configure EPs from table */ .ram_bits = 9, .fifo_cfg = jz4740_musb_fifo_cfg, .fifo_cfg_size = ARRAY_SIZE(jz4740_musb_fifo_cfg), }; static struct musb_hdrc_platform_data jz4740_musb_platform_data = { .mode = MUSB_PERIPHERAL, .config = &jz4740_musb_config, }; static int jz4740_musb_init(struct musb *musb) { usb_phy_generic_register(); musb->xceiv = usb_get_phy(USB_PHY_TYPE_USB2); if (IS_ERR(musb->xceiv)) { pr_err("HS UDC: no transceiver configured\n"); return PTR_ERR(musb->xceiv); } /* Silicon does not implement ConfigData register. * Set dyn_fifo to avoid reading EP config from hardware. */ musb->dyn_fifo = true; musb->isr = jz4740_musb_interrupt; return 0; } static int jz4740_musb_exit(struct musb *musb) { usb_put_phy(musb->xceiv); return 0; } /* * DMA has not been confirmed to work with CONFIG_USB_INVENTRA_DMA, * so let's not set up the dma function pointers yet. */ static const struct musb_platform_ops jz4740_musb_ops = { .quirks = MUSB_DMA_INVENTRA | MUSB_INDEXED_EP, .fifo_mode = 2, .init = jz4740_musb_init, .exit = jz4740_musb_exit, }; static int jz4740_probe(struct platform_device *pdev) { struct musb_hdrc_platform_data *pdata = &jz4740_musb_platform_data; struct platform_device *musb; struct jz4740_glue *glue; struct clk *clk; int ret; glue = devm_kzalloc(&pdev->dev, sizeof(*glue), GFP_KERNEL); if (!glue) return -ENOMEM; musb = platform_device_alloc("musb-hdrc", PLATFORM_DEVID_AUTO); if (!musb) { dev_err(&pdev->dev, "failed to allocate musb device\n"); return -ENOMEM; } clk = devm_clk_get(&pdev->dev, "udc"); if (IS_ERR(clk)) { dev_err(&pdev->dev, "failed to get clock\n"); ret = PTR_ERR(clk); goto err_platform_device_put; } ret = clk_prepare_enable(clk); if (ret) { dev_err(&pdev->dev, "failed to enable clock\n"); goto err_platform_device_put; } musb->dev.parent = &pdev->dev; glue->dev = &pdev->dev; glue->musb = musb; glue->clk = clk; pdata->platform_ops = &jz4740_musb_ops; platform_set_drvdata(pdev, glue); ret = platform_device_add_resources(musb, pdev->resource, pdev->num_resources); if (ret) { dev_err(&pdev->dev, "failed to add resources\n"); goto err_clk_disable; } ret = platform_device_add_data(musb, pdata, sizeof(*pdata)); if (ret) { dev_err(&pdev->dev, "failed to add platform_data\n"); goto err_clk_disable; } ret = platform_device_add(musb); if (ret) { dev_err(&pdev->dev, "failed to register musb device\n"); goto err_clk_disable; } return 0; err_clk_disable: clk_disable_unprepare(clk); err_platform_device_put: platform_device_put(musb); return ret; } static int jz4740_remove(struct platform_device *pdev) { struct jz4740_glue *glue = platform_get_drvdata(pdev); platform_device_unregister(glue->musb); usb_phy_generic_unregister(pdev); clk_disable_unprepare(glue->clk); return 0; } static struct platform_driver jz4740_driver = { .probe = jz4740_probe, .remove = jz4740_remove, .driver = { .name = "musb-jz4740", }, }; MODULE_DESCRIPTION("JZ4740 MUSB Glue Layer"); MODULE_AUTHOR("Apelete Seketeli "); MODULE_LICENSE("GPL v2"); module_platform_driver(jz4740_driver); /linux/net-next.git/patch/sound/pci/ac97?id=966d2b04e070bc040319aaebfec09e0144dc3341'>patch) tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /sound/pci/ac97 parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'sound/pci/ac97')