the write start, by adding a variation of the vfs_write_resume(9)
which accepts flags.
Use the new function to prevent a deadlock between parallel suspension
and snapshotting a UFS mount. The ffs_snapshot() code performed
vfs_write_resume() followed by vn_start_write() while owning the
snaplock. If the suspension intervene between resume and
vn_start_write(), the deadlock occured after the suspending thread
tried to lock the snaplock, most typically during the write in the
ffs_copyonwrite().
Reported and tested by: Andreas Longwitz <longwitz@incore.de>
Reviewed by: mckusick
MFC after: 2 weeks
X-MFC-note: make the vfs_write_resume(9) function a macro after the MFC,
in HEAD
There is a bug in gcc (GCC/35998) where dwarf reports
sizes of unsigned -1 (0xffffffff).
On NetBSD this generated a faulty CTF entry which then
caused a segfault in ctfmerge. The issue was worked
around in NetBSD's Dtrace but since the issue originated
in gcc, it seems reasonable to fix it here.
Upstream gcc has been slow to react to this issue and
the author that submitted the patch is not interested
in licensing the change to us, so I did an independent
workaround for the issue.
MFC after: 1 week
- Remove unused br_prod_bufs member
- Fixup r241037: buf_ring pads br_prod_* and br_cons_* members at 128
bytes, assuming a fixed cache line size for all the architectures.
However, the above mentioned revision broke the padding.
Use explicit padding to the CACHE_LINE_SIZE on the members that
mark the initial new padded sections. Of course, the padding is not
important for performance reasons in the DEBUG_BUFRING case, leaving
br_cons members to share the cache line with br_lock.
- Fixup r244732: by removing incorrectly added membar in
buf_ring_dequeue_sc() where surrounding locking shoud be enough.
- Drastically reduce the number of membar used (pratically reverting
r244732) by switching rmb() in buf_ring_dequeue_mc() and wmb() in
buf_ring_enqueue() to be complete barriers. This, along with
br_prod_bufs departure, should fix ordering issues as explained in
the provided comments.
This patch is not targeted for MFC.
Sponsored by: EMC / Isilon storage division
Reviewed by: glebius
- Add my copyright to files I've touched a lot this year.
- Add dash in front of all copyright notices according to style(9).
- Move $OpenBSD$ down below copyright notices.
- Remove extra line between cdefs.h and __FBSDID.
Basically it's replica of VersatilePB code which is replica of XBox FB
code. All of them are linear framebuffers and should have common bits
moved to reusable framework.
- Disable interrupt when updating compare value in order to
make this operation atomical
- Increase minimum period for event timer. Systimer on BCM2835
is compare timer, so if minimum period is too small it might
be less then fraction of time between "read current value" and
"set compare timer" operations. It means that when timer is armed
actual counter value is more then compare value and it will take
whole cycle (~32sec for 1MHz timer) to fire interrupt.
Submitted by: Daisuke Aoyama <aoyama at peach.ne.jp>
signal bug_ring ownership. However, instructions can be reordered
around members write leading to stale values for ie. br_prod_bufs.
Use correct memory barriers to ensure proper ordering of the
ownership tokens updates.
Sponsored by: EMC / Isilon storage division
MFC after: 2 weeks
typically do not handle the SYNCHRONIZE_CACHE command - they either
return an error or the firmware enters a reset loop.
Reviewed by: hselasky
Approved by: rstone (co-mentor)
MFC after: 2 weeks
As pointed out by hselasky@, USB_IF_CSI is the wrong macro here since we want
to declare the device's interface class, subclass and protocol, not class,
subclass and driver info.
Follow-up to r244704.
PR: kern/174707
Approved by: glebius
MFC after: 1 week
