6b6e986864
There haven been reports, that the flexcan_close() soradically hangs during simultanious ifdown, sending of CAN messages and probably open CAN bus: | (__schedule) from [<808bbd34>] (schedule+0x90/0xb8) | (schedule) from [<808bf274>] (schedule_timeout+0x1f8/0x24c) | (schedule_timeout) from [<8016be44>] (msleep+0x18/0x1c) | (msleep) from [<80746a64>] (napi_disable+0x60/0x70) | (napi_disable) from [<8052fdd0>] (flexcan_close+0x2c/0x140) | (flexcan_close) from [<80744930>] (__dev_close_many+0xb8/0xd8) | (__dev_close_many) from [<8074db9c>] (__dev_change_flags+0xd0/0x1a0) | (__dev_change_flags) from [<8074dc84>] (dev_change_flags+0x18/0x48) | (dev_change_flags) from [<80760c24>] (do_setlink+0x44c/0x7b4) | (do_setlink) from [<80761560>] (rtnl_newlink+0x374/0x68c) I was unable to reproduce the issue, but a cleanup of the flexcan close sequence has probably fixed the problem at the reporting user. This patch changes the sequence in flexcan_close() to: - stop the TX queue - disable the interrupts on the chip level and wait via free_irq() synchronously for the interrupt handler to finish - disable RX offload, which disables synchronously NAPI - disable the flexcan on the chip level - free RX offload - disable the transceiver - close the CAN device - disable the clocks Link: https://lore.kernel.org/r/20201119100917.3013281-6-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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.