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On older kernels a call to irq_set_affinity_hint does not guarantee that the IRQ affinity will be set. If nothing else on the system sets the IRQ affinity this can result in a bug in the i40e_napi_poll() routine where we notice that our interrupt fired on the "wrong" CPU according to our internal affinity_mask variable. This results in a bug where we continuously tell NAPI to stop polling to move the interrupt to a new CPU, but the CPU never changes because our affinity mask does not match the actual mask setup for the IRQ. The root problem is a mismatched affinity mask value. So lets initialize the value to cpu_possible_mask instead. This ensures that prior to the first time we get an IRQ affinity notification we'll have the mask set to include every possible CPU. We use cpu_possible_mask instead of cpu_online_mask since the former is almost certainly never going to change, while the later might change after we've made a copy. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Andrew Bowers <andrewx.bowers@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.