kernel/linux.git/drivers/dma/dmaengine.c, branch v4.14.263

dmaengine: Store module owner in dma_device struct

2020-02-28T15:36:01+00:00

[ Upstream commit dae7a589c18a4d979d5f14b09374e871b995ceb1 ] dma_chan_to_owner() dereferences the driver from the struct device to obtain the owner and call module_[get|put](). However, if the backing device is unbound before the dma_device is unregistered, the driver will be cleared and this will cause a NULL pointer dereference. Instead, store a pointer to the owner module in the dma_device struct so the module reference can be properly put when the channel is put, even if the backing device was destroyed first. This change helps to support a safer unbind of DMA engines. If the dma_device is unregistered in the driver's remove function, there's no guarantee that there are no existing clients and a users action may trigger the WARN_ONCE in dma_async_device_unregister() which is unlikely to leave the system in a consistent state. Instead, a better approach is to allow the backing driver to go away and fail any subsequent requests to it. Signed-off-by: Logan Gunthorpe Link: https://lore.kernel.org/r/20191216190120.21374-2-logang@deltatee.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin

dmaengine: remove BUG_ON while registering devices

2017-08-28T04:09:46+00:00

DMAengine core has BUG_ON to check for mandatory operations and ones based on capabilities, but they use BUG_ON, so remove and move to error returns and logging the errors gracefully Acked-by: Dan Williams Signed-off-by: Vinod Koul

dmaengine: remove DMA_SG as it is dead code in kernel

2017-08-22T03:52:11+00:00

There are no in kernel consumers for DMA_SG op. Removing operation, dead code, and test code in dmatest. Signed-off-by: Dave Jiang Reviewed-by: Linus Walleij Cc: Gary Hook Cc: Ludovic Desroches Cc: Kedareswara rao Appana Cc: Li Yang Cc: Michal Simek Signed-off-by: Vinod Koul

dmaengine: Fix array index out of bounds warning in __get_unmap_pool()

2017-03-14T04:41:27+00:00

This fixes the following warning when building with clang and CONFIG_DMA_ENGINE_RAID=n : drivers/dma/dmaengine.c:1102:11: error: array index 2 is past the end of the array (which contains 1 element) [-Werror,-Warray-bounds] return &unmap_pool[2]; ^ ~ drivers/dma/dmaengine.c:1083:1: note: array 'unmap_pool' declared here static struct dmaengine_unmap_pool unmap_pool[] = { ^ drivers/dma/dmaengine.c:1104:11: error: array index 3 is past the end of the array (which contains 1 element) [-Werror,-Warray-bounds] return &unmap_pool[3]; ^ ~ drivers/dma/dmaengine.c:1083:1: note: array 'unmap_pool' declared here static struct dmaengine_unmap_pool unmap_pool[] = { Signed-off-by: Matthias Kaehlcke Reviewed-by: Dan Williams Signed-off-by: Vinod Koul

dmaengine: Convert ID allocation to an IDA

2017-01-02T04:16:32+00:00

dmaengine currently uses an IDR to allocate DMA IDs, but it only needs to know whether IDs are in use or not; the ID to pointer functionality of the IDR is unused. That means it can use the more space-efficient IDA. Signed-off-by: Matthew Wilcox Signed-off-by: Vinod Koul

dmaengine: device must have at least one channel

2016-08-22T06:19:07+00:00

The DMA device can't be registered if it doesn't have any channels registered at all. Moreover, it leads to memory leak and is reported by kmemleak as (on 3.10 kernel, and same shall happen on mainline): unreferenced object 0xffffffc09e597240 (size 64): comm "swapper/0", pid 1, jiffies 4294877736 (age 7060.280s) hex dump (first 32 bytes): 00 00 00 00 c0 ff ff ff 30 00 00 ff 00 00 00 ff ........0....... 00 00 00 ff 00 00 00 ff 00 00 00 ff 00 00 00 ff ................ backtrace: [] create_object+0x148/0x2a0 [] kmemleak_alloc+0x80/0xbc [] kmem_cache_alloc_trace+0x120/0x1ac [] dma_async_device_register+0x160/0x46c [] foo_probe+0x1a0/0x264 [] platform_drv_probe+0x14/0x20 [] driver_probe_device+0x160/0x374 [] __driver_attach+0x60/0x90 [] bus_for_each_dev+0x7c/0xb0 [] driver_attach+0x1c/0x28 [] bus_add_driver+0x124/0x248 [] driver_register+0x90/0x110 [] platform_driver_register+0x58/0x64 [] foo_driver_init+0x10/0x1c [] do_one_initcall+0xac/0x148 [] kernel_init_freeable+0x1a0/0x258 Return -ENODEV from dma_async_device_register() on such a case. Signed-off-by: Viresh Kumar Signed-off-by: Vinod Koul

Merge branch 'topic/core' into for-linus

2016-05-17T04:43:40+00:00

dmaengine: core: Use IS_ENABLED() instead of checking for built-in or module

2016-05-14T08:02:03+00:00

The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either built-in or as a module, use that macro instead of open coding the same. Signed-off-by: Javier Martinez Canillas Signed-off-by: Vinod Koul

dmaengine: slave means at least one of DMA_SLAVE, DMA_CYCLIC

2016-05-12T05:44:56+00:00

When check for capabilities recognize slave support by either DMA_SLAVE or DMA_CYCLIC bit set. If we don't do that the user can't get a normally worked DMA support for engines that doesn't have one of the mentioned bits set. Signed-off-by: Andy Shevchenko Signed-off-by: Vinod Koul

dmaengine: core: Revert back to pr_debug in __dma_request_channel()

2016-04-13T15:39:21+00:00

Commit ef859312c3a1 ("dmaengine: core: Use dev_ functions for debug and error prints") wasn't quite right in __dma_request_channel() by claiming that all pr_ prints have valid DMA channel pointer. Obviously it is not true as __dma_request_channel() is looking for a channel and returns NULL if it does not find it. Prevent this potential NULL pointer dereference by reverting back to pr_debug(). Signed-off-by: Jarkko Nikula Reported-by: Dan Carpenter Signed-off-by: Vinod Koul