[ Upstream commit 9ead7e74bfd6dd54db12ef133b8604add72511de ] Ice driver allocates per cpu XDP queues so that redirect path can safely use smp_processor_id() as an index to the array. At the same time though, XDP rings are used to pick NAPI context to call napi_schedule() or set NAPIF_STATE_MISSED. When user reduces queue count, say to 8, and num_possible_cpus() of underlying platform is 44, then this means queue vectors with correlated NAPI contexts will carry several XDP queues. This in turn can result in a broken behavior where NAPI context of interest will never be scheduled and AF_XDP socket will not process any traffic. To fix this, let us change the way how XDP rings are assigned to Rx rings and use this information later on when setting ice_tx_ring::xsk_pool pointer. For each Rx ring, grab the associated queue vector and walk through Tx ring's linked list. Once we stumble upon XDP ring in it, assign this ring to ice_rx_ring::xdp_ring. Previous [0] approach of fixing this issue was for txonly scenario because of the described grouping of XDP rings across queue vectors. So, relying on Rx ring meant that NAPI context could be scheduled with a queue vector without XDP ring with associated XSK pool. [0]: https://lore.kernel.org/netdev/20220707161128.54215-1-maciej.fijalkowski@intel.com/ Fixes: 2d4238f55697 ("ice: Add support for AF_XDP") Fixes: 22bf877e528f ("ice: introduce XDP_TX fallback path") Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com> Signed-off-by: Sasha Levin <sashal@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.
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