kernel/linux.git/drivers/dma/dmaengine.c, branch linux-5.11.y

dmaengine: Fix a double free in dma_async_device_register

2021-04-21T11:13:18+00:00

[ Upstream commit ea45b6008f8095db0cc09ad6e03c7785c2986197 ] In the first list_for_each_entry() macro of dma_async_device_register, it gets the chan from list and calls __dma_async_device_channel_register (..,chan). We can see that chan->local is allocated by alloc_percpu() and it is freed chan->local by free_percpu(chan->local) when __dma_async_device_channel_register() failed. But after __dma_async_device_channel_register() failed, the caller will goto err_out and freed the chan->local in the second time by free_percpu(). The cause of this problem is forget to set chan->local to NULL when chan->local was freed in __dma_async_device_channel_register(). My patch sets chan->local to NULL when the callee failed to avoid double free. Fixes: d2fb0a0438384 ("dmaengine: break out channel registration") Signed-off-by: Lv Yunlong Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/20210331014458.3944-1-lyl2019@mail.ustc.edu.cn Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin

dmaengine: move channel device_node deletion to driver

2021-01-19T16:40:52+00:00

Channel device_node deletion is managed by the device driver rather than the dmaengine core. The deletion was accidentally introduced when making channel unregister dynamic. It causes xilinx_dma module to crash on unload as reported by Radhey. Remove chan->device_node delete in dmaengine and also fix up idxd driver. [ 42.142705] Internal error: Oops: 96000044 [#1] SMP [ 42.147566] Modules linked in: xilinx_dma(-) clk_xlnx_clock_wizard uio_pdrv_genirq [ 42.155139] CPU: 1 PID: 2075 Comm: rmmod Not tainted 5.10.1-00026-g3a2e6dd7a05-dirty #192 [ 42.163302] Hardware name: Enclustra XU5 SOM (DT) [ 42.167992] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--) [ 42.173996] pc : xilinx_dma_chan_remove+0x74/0xa0 [xilinx_dma] [ 42.179815] lr : xilinx_dma_chan_remove+0x70/0xa0 [xilinx_dma] [ 42.185636] sp : ffffffc01112bca0 [ 42.188935] x29: ffffffc01112bca0 x28: ffffff80402ea640 xilinx_dma_chan_remove+0x74/0xa0: __list_del at ./include/linux/list.h:112 (inlined by) __list_del_entry at./include/linux/list.h:135 (inlined by) list_del at ./include/linux/list.h:146 (inlined by) xilinx_dma_chan_remove at drivers/dma/xilinx/xilinx_dma.c:2546 Fixes: e81274cd6b52 ("dmaengine: add support to dynamic register/unregister of channels") Reported-by: Radhey Shyam Pandey Signed-off-by: Dave Jiang Tested-by: Radhey Shyam Pandey Link: https://lore.kernel.org/r/161099092469.2495902.5064826526660062342.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Vinod Koul Cc: stable@vger.kernel.org # 5.9+

dmaengine: fix error codes in channel_register()

2020-11-18T12:21:51+00:00

The error codes were not set on some of these error paths. Also the error handling was more confusing than it needed to be so I cleaned it up and shuffled it around a bit. Fixes: d2fb0a043838 ("dmaengine: break out channel registration") Signed-off-by: Dan Carpenter Reviewed-by: Peter Ujfalusi Link: https://lore.kernel.org/r/20201113101631.GE168908@mwanda Signed-off-by: Vinod Koul

dmaengine: Save few bytes and increase readability of dma_request_chan()

2020-09-03T06:52:35+00:00

Split IS_ERR_OR_NULL() check followed by additional conditional to two simple conditionals. This increases readability and saves memory: Function old new delta dma_request_chan 700 697 -3 Total: Before=10224, After=10221, chg -0.03% Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200828144519.14483-1-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul

dmaengine: Mark dma_request_slave_channel() deprecated

2020-09-03T06:51:03+00:00

New drivers should use dma_request_chan() instead dma_request_slave_channel() dma_request_slave_channel() is a simple wrapper for dma_request_chan() eating up the error code for channel request failure and makes deferred probing impossible. Move the dma_request_slave_channel() into the header as inline function, mark it as deprecated. Signed-off-by: Peter Ujfalusi Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200828110507.22407-1-peter.ujfalusi@ti.com Signed-off-by: Vinod Koul

dmaengine: Introduce DMA-device device_caps callback

2020-07-27T09:00:55+00:00

There are DMA devices (like ours version of Synopsys DW DMAC) which have DMA capabilities non-uniformly redistributed between the device channels. In order to provide a way of exposing the channel-specific parameters to the DMA engine consumers, we introduce a new DMA-device callback. In case if provided it gets called from the dma_get_slave_caps() method and is able to override the generic DMA-device capabilities. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200723005848.31907-6-Sergey.Semin@baikalelectronics.ru Signed-off-by: Vinod Koul

dmaengine: Introduce max SG burst capability

2020-07-27T09:00:54+00:00

Some devices may lack the support of the hardware accelerated SG list entries automatic walking through and execution. In this case a burden of the SG list traversal and DMA engine re-initialization lies on the DMA engine driver (normally implemented by using a DMA transfer completion IRQ to recharge the DMA device with a next SG list entry). But such solution may not be suitable for some DMA consumers. In particular SPI devices need both Tx and Rx DMA channels work synchronously in order to avoid the Rx FIFO overflow. In case if Rx DMA channel is paused for some time while the Tx DMA channel works implicitly pulling data into the Rx FIFO, the later will be eventually overflown, which will cause the data loss. So if SG list entries aren't automatically fetched by the DMA engine, but are one-by-one manually selected for execution in the ISRs/deferred work/etc., such problem will eventually happen due to the non-deterministic latencies of the service execution. In order to let the DMA consumer know about the DMA device capabilities regarding the hardware accelerated SG list traversal we introduce the max_sg_burst capability. It is supposed to be initialized by the DMA engine driver with 0 if there is no limitation of the number of SG entries atomically executed and with non-zero value if there is such constraints, so the upper limit is determined by the number set to the property. Suggested-by: Andy Shevchenko Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200723005848.31907-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Vinod Koul

dmaengine: Introduce min burst length capability

2020-07-27T09:00:54+00:00

Some hardware aside from default 0/1 may have greater minimum burst transactions length constraints. Here we introduce the DMA device and slave capability, which if required can be initialized by the DMA engine driver with the device-specific value. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200723005848.31907-4-Sergey.Semin@baikalelectronics.ru Signed-off-by: Vinod Koul

Merge tag 'dmaengine-5.8-rc1' of git://git.infradead.org/users/vkoul/slave-dma

2020-06-10T18:03:04+00:00

Pull dmaengine updates from Vinod Koul: "A fairly small dmaengine update which includes mostly driver updates (dmatest, dw-edma, ioat, mmp-tdma and k3-udma) along with Renesas binding update to json-schema" * tag 'dmaengine-5.8-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (39 commits) dmaengine: imx-sdma: initialize all script addresses dmaengine: ti: k3-udma: Use proper return code in alloc_chan_resources dmaengine: ti: k3-udma: Remove udma_chan.in_ring_cnt dmaengine: ti: k3-udma: Add missing dma_sync call for rx flush descriptor dmaengine: at_xdmac: Replace zero-length array with flexible-array dmaengine: at_hdmac: Replace zero-length array with flexible-array dmaengine: qcom: bam_dma: Replace zero-length array with flexible-array dmaengine: ti: k3-udma: Use PTR_ERR_OR_ZERO() to simplify code dmaengine: moxart-dma: Drop pointless static qualifier in moxart_probe() dmaengine: sf-pdma: Simplify the error handling path in 'sf_pdma_probe()' dmaengine: qcom_hidma: use true,false for bool variable dmaengine: dw-edma: support local dma device transfer semantics dmaengine: Fix doc strings to satisfy validation script dmaengine: Include dmaengine.h into dmaengine.c dmaengine: dmatest: Describe members of struct dmatest_info dmaengine: dmatest: Describe members of struct dmatest_params dmaengine: dmatest: Allow negative timeout value to specify infinite wait Revert "dmaengine: dmatest: timeout value of -1 should specify infinite wait" dmaengine: stm32-dma: direct mode support through device tree dt-bindings: dma: add direct mode support through device tree in stm32-dma ...

dmaengine: Fix doc strings to satisfy validation script

2020-05-04T05:28:03+00:00

The validation kernel doc script complains about undescribed function parameters .../dmaengine.c:155: warning: Function parameter or member 'dev' not descr ibed in 'dev_to_dma_chan' .../dmaengine.c:251: warning: cannot understand function prototype: 'dma_cap_mask_t dma_cap_mask_all; ' .../dmaengine.c:257: warning: cannot understand function prototype: 'struct dma_chan_tbl_ent ' .../dmaengine.c:264: warning: cannot understand function prototype: 'struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END]; ' .../dmaengine.c:304: warning: Function parameter or member 'chan' not described in 'dma_chan_is_local' .../dmaengine.c:304: warning: Function parameter or member 'cpu' not described in 'dma_chan_is_local' .../dmaengine.c:414: warning: Function parameter or member 'chan' not described in 'balance_ref_count' .../dmaengine.c:447: warning: Function parameter or member 'chan' not described in 'dma_chan_get' .../dmaengine.c:494: warning: Function parameter or member 'chan' not described in 'dma_chan_put' Add descriptions to the function parameters and in some cases update existing text as well. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200429122151.50989-2-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul