When MTU is changed, FDMA is required to calculate what is the maximum size of the frame that it can received. So it can calculate what is the page order needed to allocate for the received frames. The first problem was that, when the max MTU was calculated it was reading the value from dev and not from HW, so in this way it was missing L2 header + the FCS. The other problem was that once the skb is created using __build_skb_around, it would reserve some space for skb_shared_info. So if we received a frame which size is at the limit of the page order then the creating will failed because it would not have space to put all the data. Fixes: 2ea1cbac267e ("net: lan966x: Update FDMA to change MTU.") Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com> Signed-off-by: Jakub Kicinski <kuba@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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