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Injecting errors on the PCI slot while the driver is handling NVMe I/O will cause crashes and hangs. There are several rather difficult scenarios occurring. The main issue is that the adapter can report a PCI error before or simultaneously to the PCI subsystem reporting the error. Both paths have different entry points and currently there is no interlock between them. Thus multiple teardown paths are competing and all heck breaks loose. Complicating things is the NVMs path. To a large degree, I/O was able to be shutdown for a full FC port on the SCSI stack. But on NVMe, there isn't a similar call. At best, it works on a per-controller basis, but even at the controller level, it's a controller "reset" call. All of which means I/O is still flowing on different CPUs with reset paths expecting hw access (mailbox commands) to execute properly. The following modifications are made: - A new flag is set in PCI error entrypoints so the driver can track being called by that path. - An interlock is added in the SLI hw error path and the PCI error path such that only one of the paths proceeds with the teardown logic. - RPI cleanup is patched such that RPIs are marked unregistered w/o mbx cmds in cases of hw error. - If entering the SLI port re-init calls, a case where SLI error teardown was quick and beat the PCI calls now reporting error, check whether the SLI port is still live on the PCI bus. - In the PCI reset code to bring the adapter back, recheck the IRQ settings. Different checks for SLI3 vs SLI4. - In I/O completions, that may be called as part of the cleanup or underway just before the hw error, check the state of the adapter. If in error, shortcut handling that would expect further adapter completions as the hw error won't be sending them. - In routines waiting on I/O completions, which may have been in progress prior to the hw error, detect the device is being torn down and abort from their waits and just give up. This points to a larger issue in the driver on ref-counting for data structures, as it doesn't have ref-counting on q and port structures. We'll do this fix for now as it would be a major rework to be done differently. - Fix the NVMe cleanup to simulate NVMe I/O completions if I/O is being failed back due to hw error. - In I/O buf allocation, done at the start of new I/Os, check hw state and fail if hw error. Link: https://lore.kernel.org/r/20210910233159.115896-10-jsmart2021@gmail.com Co-developed-by: Justin Tee <justin.tee@broadcom.com> Signed-off-by: Justin Tee <justin.tee@broadcom.com> Signed-off-by: James Smart <jsmart2021@gmail.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.