that the events queue is empty. In other case we're able to hit the race
where for example da0s1 is tasted by some other class, which means that
da0 is open with exclusive bit set, which means that we can't open da0
for writing if it is our component.
Reported by: Attila Nagy <bra@fsn.hu> (and somebody else sometime ago,
but I cannot find who it was)
transfer timeouts that typically cause a transfer to be completed
twice, resulting in panics and page faults:
o A transfer completion interrupt could arrive while an abort_task
event was set up, so the transfer would be aborted after it had
completed. This is very easy to reproduce. Fix this by setting
the transfer status to USBD_TIMEOUT before scheduling the
abort_task so that the transfer completion code will ignore it.
o The transfer completion code could execute concurrently with the
timeout callout, leaving the callout blocked (e.g. waiting for
Giant) while the transfer completion code runs. In this case,
callout_stop() does not prevent the callout from running, so
again the timeout code would run after the transfer was complete.
Handle this case by checking the return value from callout_stop(),
and ignoring the transfer if the callout could not be removed.
o Finally, protect against a timeout callout occurring while a
transfer is being aborted by another process. Here we arrange
for the timeout processing to ignore the transfer, and use
callout_drain() to ensure that the callout has really gone before
completing the transfer.
This was tested by repeatedly performing USB transfers with a timeout
set to approximately the same as the normal transfer completion
time. In the PR below, apparently this occurred by accident with a
particular printer and the default timeout.
PR: kern/71491
changes associated with adding System V IPC support. This will prevent
old modules from being used with the new kernel, and new modules from
being used with the old kernel.
These can be used to pass extra options to the mdmfs(8) utility,
to customize the finer details of the md file system creation
(i.e. to turn on/off softupdates, to specify a default owner for md
filesystem, etc).
Use these two new flags to mount tmpmfs and varmfs without
softupdates, since it doesn't make much sense to use SU on
malloc-backed file systems.
Reviewed by: mtm
Inspired by: J. D. Bronson, jbronson at wixb dot com
appropriate for different tag requirements. With the former global pool,
bounce pages might get allocated that are appropriate for one tag, but not
appropriate for another, but the system had no way to distinguish between them.
Now zones with distinct attributes are created to hold pages, and each tag
that requires bouncing is associated with a zone. New zones are created as
needed if no existing zones can meet the requirements of the tag. Stats for
each zone are tracked via the hw.busdma sysctl node.
This should help drivers that are failing with mysterious data corruption.
MFC After: 1 week
changes, start on a new line. Insertion of a filename will keep the
diff limited to the block of filenames that have the same first letter
instead of creating a huge diff. While here, move remote.c after the
remote-*.c files and move tui.c after the tui-*.c files. This matches
the order of ls(1) and makes it easier to compare object files created
by a stock gdb(1) build with the list of files we have here.
This is a non-functional change only.
