07df385e64
In the PF interrupt handler, the interrupt is disabled for a set of VFs by writing to the interrupt source mask register, ERRMSK. The interrupt is re-enabled in the bottom half handler by writing to the same CSR. This is done through the functions enable_vf2pf_interrupts() and disable_vf2pf_interrupts() which perform a read-modify-write operation on the ERRMSK registers to mask and unmask the source of interrupt. There can be a race condition where the top half handler for one VF interrupt runs just as the bottom half for another VF is about to re-enable the interrupt. Depending on whether the top or bottom half updates the CSR first, this would result either in a spurious interrupt or in the interrupt not being re-enabled. This patch protects the access of ERRMSK with a spinlock. The functions adf_enable_vf2pf_interrupts() and adf_disable_vf2pf_interrupts() have been changed to acquire a spin lock before accessing and modifying the ERRMSK registers. These functions use spin_lock_irqsave() to disable IRQs and avoid potential deadlocks. In addition, the function adf_disable_vf2pf_interrupts_irq() has been added. This uses spin_lock() and it is meant to be used in the top half only. Signed-off-by: Kanchana Velusamy <kanchanax.velusamy@intel.com> Co-developed-by: Marco Chiappero <marco.chiappero@intel.com> Signed-off-by: Marco Chiappero <marco.chiappero@intel.com> Co-developed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com> Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com> Reviewed-by: Fiona Trahe <fiona.trahe@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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.