From: Huang Shijie <sjhuang@iluvatar.ai> To: Peter Ujfalusi <peter.ujfalusi@ti.com> Cc: vkoul@kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, dave.jiang@intel.com, radhey.shyam.pandey@xilinx.com, appana.durga.rao@xilinx.com, jmkrzyszt@gmail.com, gomonovych@gmail.com, keescook@chromium.org, horms+renesas@verge.net.au, geert+renesas@glider.be, shawnguo@kernel.org, baoyou.xie@linaro.org, michal.simek@xilinx.com, baohua@kernel.org, ludovic.desroches@microchip.com, linus.walleij@linaro.org, david.brown@linaro.org Subject: [09/46] dmaengine: cppi41: use dmaenginem_async_device_register to simplify the code Date: Mon, 6 Aug 2018 11:28:47 +0800 [thread overview] Message-ID: <20180806032847.GA4452@hsj-Precision-5520> (raw) On Fri, Aug 03, 2018 at 10:55:25AM +0300, Peter Ujfalusi wrote: > > > On 2018-08-03 10:19, Huang Shijie wrote: > > Use dmaenginem_async_device_register to simplify the code: > > remove dma_async_device_unregister > > > > Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai> > > --- > > drivers/dma/ti/cppi41.c | 7 ++----- > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/dma/ti/cppi41.c b/drivers/dma/ti/cppi41.c > > index 1497da367710..d2998a19ed2e 100644 > > --- a/drivers/dma/ti/cppi41.c > > +++ b/drivers/dma/ti/cppi41.c > > @@ -1096,21 +1096,19 @@ static int cppi41_dma_probe(struct platform_device *pdev) > > goto err_chans; > > cdd->irq = irq; > > > > - ret = dma_async_device_register(&cdd->ddev); > > + ret = dmaenginem_async_device_register(&cdd->ddev); > > if (ret) > > goto err_chans; > > > > ret = of_dma_controller_register(dev->of_node, > > cppi41_dma_xlate, &cpp41_dma_info); > > if (ret) > > - goto err_of; > > + goto err_chans; > > > > pm_runtime_mark_last_busy(dev); > > pm_runtime_put_autosuspend(dev); > > > > return 0; > > -err_of: > > - dma_async_device_unregister(&cdd->ddev); > > err_chans: > > deinit_cppi41(dev, cdd); > > err_init_cppi: > > @@ -1132,7 +1130,6 @@ static int cppi41_dma_remove(struct platform_device *pdev) > > dev_err(&pdev->dev, "%s could not pm_runtime_get: %i\n", > > __func__, error); > > of_dma_controller_free(pdev->dev.of_node); > > - dma_async_device_unregister(&cdd->ddev); > > If I read the code right then this is not safe. I read the code again, and find it is okay. > We would have deinitalized cppi41 driver which is not functional, but we > will still have the dma device registered and if a channel is requested > we will have kernel crash. We cannot succeed to request a channel when the drv->remove() is called. Please see __device_release_driver: --------------------------------------------------------------------- if (dev->bus && dev->bus->remove) dev->bus->remove(dev); else if (drv->remove) drv->remove(dev); device_links_driver_cleanup(dev); dma_deconfigure(dev); devres_release_all(dev); ============> Devres release --------------------------------------------------------------------- For the DMA engine driver, there is only one case which will calls drv->remove(): Use the rmmod(or modprobe -r). We do not use the device_link_add API for DMA engines. And we not manually call the device_release_driver() for DMA engines. But when we use the rmmod, the module state will be MODULE_STATE_GOING. In the find_candidate(), dma_chan_get() will fail. And we cannot get a channel. Please correct me if I am wrong :) Thanks Huang Shijie --- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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From: Huang Shijie <sjhuang@iluvatar.ai> To: Peter Ujfalusi <peter.ujfalusi@ti.com> Cc: vkoul@kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, dave.jiang@intel.com, radhey.shyam.pandey@xilinx.com, appana.durga.rao@xilinx.com, jmkrzyszt@gmail.com, gomonovych@gmail.com, keescook@chromium.org, horms+renesas@verge.net.au, geert+renesas@glider.be, shawnguo@kernel.org, baoyou.xie@linaro.org, michal.simek@xilinx.com, baohua@kernel.org, ludovic.desroches@microchip.com, linus.walleij@linaro.org, david.brown@linaro.org Subject: Re: [PATCH 09/46] dmaengine: cppi41: use dmaenginem_async_device_register to simplify the code Date: Mon, 6 Aug 2018 11:28:47 +0800 [thread overview] Message-ID: <20180806032847.GA4452@hsj-Precision-5520> (raw) In-Reply-To: <43458794-d124-13df-c944-e473dc8ee1c2@ti.com> On Fri, Aug 03, 2018 at 10:55:25AM +0300, Peter Ujfalusi wrote: > > > On 2018-08-03 10:19, Huang Shijie wrote: > > Use dmaenginem_async_device_register to simplify the code: > > remove dma_async_device_unregister > > > > Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai> > > --- > > drivers/dma/ti/cppi41.c | 7 ++----- > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/dma/ti/cppi41.c b/drivers/dma/ti/cppi41.c > > index 1497da367710..d2998a19ed2e 100644 > > --- a/drivers/dma/ti/cppi41.c > > +++ b/drivers/dma/ti/cppi41.c > > @@ -1096,21 +1096,19 @@ static int cppi41_dma_probe(struct platform_device *pdev) > > goto err_chans; > > cdd->irq = irq; > > > > - ret = dma_async_device_register(&cdd->ddev); > > + ret = dmaenginem_async_device_register(&cdd->ddev); > > if (ret) > > goto err_chans; > > > > ret = of_dma_controller_register(dev->of_node, > > cppi41_dma_xlate, &cpp41_dma_info); > > if (ret) > > - goto err_of; > > + goto err_chans; > > > > pm_runtime_mark_last_busy(dev); > > pm_runtime_put_autosuspend(dev); > > > > return 0; > > -err_of: > > - dma_async_device_unregister(&cdd->ddev); > > err_chans: > > deinit_cppi41(dev, cdd); > > err_init_cppi: > > @@ -1132,7 +1130,6 @@ static int cppi41_dma_remove(struct platform_device *pdev) > > dev_err(&pdev->dev, "%s could not pm_runtime_get: %i\n", > > __func__, error); > > of_dma_controller_free(pdev->dev.of_node); > > - dma_async_device_unregister(&cdd->ddev); > > If I read the code right then this is not safe. I read the code again, and find it is okay. > We would have deinitalized cppi41 driver which is not functional, but we > will still have the dma device registered and if a channel is requested > we will have kernel crash. We cannot succeed to request a channel when the drv->remove() is called. Please see __device_release_driver: --------------------------------------------------------------------- if (dev->bus && dev->bus->remove) dev->bus->remove(dev); else if (drv->remove) drv->remove(dev); device_links_driver_cleanup(dev); dma_deconfigure(dev); devres_release_all(dev); ============> Devres release --------------------------------------------------------------------- For the DMA engine driver, there is only one case which will calls drv->remove(): Use the rmmod(or modprobe -r). We do not use the device_link_add API for DMA engines. And we not manually call the device_release_driver() for DMA engines. But when we use the rmmod, the module state will be MODULE_STATE_GOING. In the find_candidate(), dma_chan_get() will fail. And we cannot get a channel. Please correct me if I am wrong :) Thanks Huang Shijie
next reply other threads:[~2018-08-06 3:28 UTC|newest] Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-08-06 3:28 Huang Shijie [this message] 2018-08-06 3:28 ` [PATCH 09/46] dmaengine: cppi41: use dmaenginem_async_device_register to simplify the code Huang Shijie -- strict thread matches above, loose matches on Subject: below -- 2018-08-09 2:36 [07/46] dmaengine: omap-dma: " Vinod Koul 2018-08-09 2:36 ` [PATCH 07/46] " Vinod 2018-08-08 7:16 [09/46] dmaengine: cppi41: " Tony Lindgren 2018-08-08 7:16 ` [PATCH 09/46] " Tony Lindgren 2018-08-07 7:16 [09/46] " Huang Shijie 2018-08-07 7:16 ` [PATCH 09/46] " Huang Shijie 2018-08-07 7:01 [09/46] " Peter Ujfalusi 2018-08-07 7:01 ` [PATCH 09/46] " Peter Ujfalusi 2018-08-03 8:10 [17/46] dmaengine: stm32-mdma: " Pierre Yves MORDRET 2018-08-03 8:10 ` [PATCH 17/46] " Pierre Yves MORDRET 2018-08-03 8:02 [09/46] dmaengine: cppi41: " Huang Shijie 2018-08-03 8:02 ` [PATCH 09/46] " Huang Shijie 2018-08-03 7:55 [09/46] " Peter Ujfalusi 2018-08-03 7:55 ` [PATCH 09/46] " Peter Ujfalusi 2018-08-03 7:54 [08/46] dmaengine: edma: " Huang Shijie 2018-08-03 7:54 ` [PATCH 08/46] " Huang Shijie 2018-08-03 7:52 [07/46] dmaengine: omap-dma: " Huang Shijie 2018-08-03 7:52 ` [PATCH 07/46] " Huang Shijie 2018-08-03 7:50 [08/46] dmaengine: edma: " Peter Ujfalusi 2018-08-03 7:50 ` [PATCH 08/46] " Peter Ujfalusi 2018-08-03 7:47 [07/46] dmaengine: omap-dma: " Peter Ujfalusi 2018-08-03 7:47 ` [PATCH 07/46] " Peter Ujfalusi 2018-08-03 7:20 [46/46] dmaengine: add COMPILE_TEST for the drivers Huang Shijie 2018-08-03 7:20 ` [PATCH 46/46] " Huang Shijie 2018-08-03 7:20 [45/46] dmaengine: dma-axi-dmac: use dmaenginem_async_device_register to simplify the code Huang Shijie 2018-08-03 7:20 ` [PATCH 45/46] " Huang Shijie 2018-08-03 7:20 [44/46] dmaengine: dma-jz4740: " Huang Shijie 2018-08-03 7:20 ` [PATCH 44/46] " Huang Shijie 2018-08-03 7:20 [43/46] dmaengine: dma-jz4780: " Huang Shijie 2018-08-03 7:20 ` [PATCH 43/46] " Huang Shijie 2018-08-03 7:20 [42/46] dmaengine: at_xdmac: " Huang Shijie 2018-08-03 7:20 ` [PATCH 42/46] " Huang Shijie 2018-08-03 7:20 [41/46] dmaengine: at_hdmac: " Huang Shijie 2018-08-03 7:20 ` [PATCH 41/46] " Huang Shijie 2018-08-03 7:20 [40/46] dmaengine: fsl-edma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 40/46] " Huang Shijie 2018-08-03 7:20 [39/46] dmaengine: img-mdc-dma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 39/46] " Huang Shijie 2018-08-03 7:20 [38/46] dmaengine: imx-dma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 38/46] " Huang Shijie 2018-08-03 7:20 [37/46] dmaengine: imx-sdma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 37/46] " Huang Shijie 2018-08-03 7:20 [36/46] dmaengine: k3dma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 36/46] " Huang Shijie 2018-08-03 7:20 [35/46] dmaengine: mtk-hsdma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 35/46] " Huang Shijie 2018-08-03 7:20 [34/46] dmaengine: mxs-dma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 34/46] " Huang Shijie 2018-08-03 7:20 [33/46] dmaengine: pch_dma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 33/46] " Huang Shijie 2018-08-03 7:20 [32/46] dmaengine: pl330: " Huang Shijie 2018-08-03 7:20 ` [PATCH 32/46] " Huang Shijie 2018-08-03 7:20 [31/46] dmaengine: moxart-dma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 31/46] " Huang Shijie 2018-08-03 7:20 [30/46] dmaengine: pxa_dma: " Huang Shijie 2018-08-03 7:20 ` [PATCH 30/46] " Huang Shijie 2018-08-03 7:19 [29/46] dmaengine: hidma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 29/46] " Huang Shijie 2018-08-03 7:19 [28/46] dmaengine: rcar-dmac: " Huang Shijie 2018-08-03 7:19 ` [PATCH 28/46] " Huang Shijie 2018-08-03 7:19 [27/46] dmaengine: usb-dmac: " Huang Shijie 2018-08-03 7:19 ` [PATCH 27/46] " Huang Shijie 2018-08-03 7:19 [26/46] dmaengine: shdmac: " Huang Shijie 2018-08-03 7:19 ` [PATCH 26/46] " Huang Shijie 2018-08-03 7:19 [25/46] dmaengine: mmp_tdma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 25/46] " Huang Shijie 2018-08-03 7:19 [24/46] dmaengine: nbpfaxi: " Huang Shijie 2018-08-03 7:19 ` [PATCH 24/46] " Huang Shijie 2018-08-03 7:19 [23/46] dmaengine: sa11x0-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 23/46] " Huang Shijie 2018-08-03 7:19 [22/46] dmaengine: sudmac: " Huang Shijie 2018-08-03 7:19 ` [PATCH 22/46] " Huang Shijie 2018-08-03 7:19 [21/46] dmaengine: bam_dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 21/46] " Huang Shijie 2018-08-03 7:19 [20/46] dmaengine: sirf-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 20/46] " Huang Shijie 2018-08-03 7:19 [19/46] dmaengine: sprd-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 19/46] " Huang Shijie 2018-08-03 7:19 [18/46] dmaengine: stm32-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 18/46] " Huang Shijie 2018-08-03 7:19 [17/46] dmaengine: stm32-mdma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 17/46] " Huang Shijie 2018-08-03 7:19 [16/46] dmaengine: ste_dma40: " Huang Shijie 2018-08-03 7:19 ` [PATCH 16/46] " Huang Shijie 2018-08-03 7:19 [15/46] dmaengine: s3c24xx-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 15/46] " Huang Shijie 2018-08-03 7:19 [14/46] dmaengine: coh901318: " Huang Shijie 2018-08-03 7:19 ` [PATCH 14/46] " Huang Shijie 2018-08-03 7:19 [13/46] dmaengine: sun4i-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 13/46] " Huang Shijie 2018-08-03 7:19 [12/46] dmaengine: sun6i-dma: use helper dmaenginem_async_device_register Huang Shijie 2018-08-03 7:19 ` [PATCH 12/46] " Huang Shijie 2018-08-03 7:19 [11/46] dmaengine: tegra20-apb-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 11/46] " Huang Shijie 2018-08-03 7:19 [10/46] dmaengine: tegra210-adma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 10/46] " Huang Shijie 2018-08-03 7:19 [09/46] dmaengine: cppi41: use dmaenginem_async_device_register to simplify the code Huang Shijie 2018-08-03 7:19 ` [PATCH 09/46] " Huang Shijie 2018-08-03 7:19 [08/46] dmaengine: edma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 08/46] " Huang Shijie 2018-08-03 7:19 [07/46] dmaengine: omap-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 07/46] " Huang Shijie 2018-08-03 7:19 [06/46] dmaengine: timb_dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 06/46] " Huang Shijie 2018-08-03 7:19 [05/46] dmaengine: txx9dmac: " Huang Shijie 2018-08-03 7:19 ` [PATCH 05/46] " Huang Shijie 2018-08-03 7:19 [04/46] dmaengine: xgene-dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 04/46] " Huang Shijie 2018-08-03 7:19 [03/46] dmaengine: xilinx_dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 03/46] " Huang Shijie 2018-08-03 7:19 [02/46] dmaengine: zynqmp_dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 02/46] " Huang Shijie 2018-08-03 7:19 [01/46] dmaengine: zx_dma: " Huang Shijie 2018-08-03 7:19 ` [PATCH 01/46] " Huang Shijie 2018-08-03 7:19 [PATCH 00/46] Use dmaenginem_async_device_register to simplify code Huang Shijie 2018-08-03 7:51 ` Lars-Peter Clausen 2018-08-03 7:59 ` Huang Shijie 2018-08-03 8:20 ` Peter Ujfalusi 2018-08-03 8:48 ` Huang Shijie 2018-08-05 1:03 ` Huang Shijie
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