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In schedule_resp(), under certain conditions we check whether the per-device queue is full (num_in_q == queue depth - 1) and we may inject a "task set full" (TSF) error if it is. However how we read num_in_q is racy - many threads may see the same "queue is full" value (and also issue a TSF). There is per-queue locking in reading per-device num_in_q, but that would not help. Replace how we read num_in_q at this location with a call to scsi_device_busy(). Calling scsi_device_busy() is likewise racy (as reading num_in_q), so nothing lost or gained. Calling scsi_device_busy() is also slow as it needs to read all bits in the per-device budget bitmap, but we can live with that since we're just a simulator and it's only under a certain configs which we would see this. Also move the "task set full" print earlier as it would only be called now under this condition. However, previously it may not have been called - like returning early - but keep it simple and always call it. At this point we can drop sdebug_dev_info.num_in_q - it is difficult to maintain properly and adds extra normal case command processing. Signed-off-by: John Garry <john.g.garry@oracle.com> Acked-by: Douglas Gilbert <dgilbert@interlog.com> Link: https://lore.kernel.org/r/20230313093114.1498305-10-john.g.garry@oracle.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.