078a650614
Fix the following deadlocks: 1/ atc_handle_cyclic() and atc_chain_complete() called dmaengine_desc_get_callback_invoke() while wrongly holding the atchan->lock. Clients can set the callback to dmaengine_terminate_sync() which will end up trying to get the same lock, thus a deadlock occurred. 2/ dma_run_dependencies() was called with the atchan->lock held, but the method calls device_issue_pending() which tries to get the same lock, and so a deadlock occurred. The driver must not hold the lock when invoking the callback or when running dependencies. Releasing the spinlock within a called function before calling the callback is not a nice thing to do -> called functions become non-atomic when called within an atomic region. Thus the lock is now taken in the child routines whereever is needed. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> Link: https://lore.kernel.org/r/20200123140237.125799-6-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.