drbd: protocol compatibility for maximum packet sizes

Two missing corner cases to the "maximum packet size" handshake.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Track the reasons to suspend IO in dedicated state bits

There are three ways to get IO suspended:

 * Loss of any access to data
 * Fence-peer-handler running
 * User requested to suspend IO

Track those in different bits, so that one condition clearing its
state bit does not interfere with the other two conditions.

Only when the user resumes IO he overrules all three bits.

The fact is hidden from the user, he sees only a single suspend
bit.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: DIV_ROUND_UP not needed here

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Fixed compatibility with protocol versions smaller than 95

Forgot to consider the max size for the resync requests.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: fix for spurious full sync (becoming sync target looked like invalidate)

If a synctarget lost connection while being WFSyncUUID,
due to "state sanitizing", the attempted state change to SyncTarget
looked like an "invalidate" to after_state_ch() later,
thus caused a full sync on next handshake (Bug #318).

drbd0: PingAck did not arrive in time.
drbd0: peer( Primary -> Unknown ) conn( WFSyncUUID -> NetworkFailure ) pdsk( UpToDate -> DUnknown )

        from  : { cs:NetworkFailure ro:Secondary/Unknown ds:UpToDate/DUnknown r--- }
        to    : { cs:SyncTarget ro:Secondary/Unknown ds:Inconsistent/DUnknown r--- }
        after sanizising, resulted in
        state: { cs:NetworkFailure ro:Secondary/Unknown ds:Inconsistent/DUnknown r--- }
        drbd0: disk( UpToDate -> Inconsistent )

Fix:
don't mask state transition errors in "sanitizing",
so the requested state change to SyncTarget fails,
instead of being implicitly "remaped" to invalidate.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: cosmetic, don't report resync for online-verify

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: fix spurious protocol error

If we cannot satisfy a request (because our disk just broke),
we still need to drain the payload.  Or we'll get a protocol error
when interpreting the payload as DRBD packet header.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: fix potential kernel BUG (NULL deref)

BUG trace would look like:
 lc_find
 drbd_rs_complete_io
 got_OVResult
 drbd_asender

Could be triggered by explicit, or IO-error policy based,
detach during online-verify.

We may only dereference mdev->resync, if we first get_ldev(), as the
disk may break any time, causing mdev->resync to disappear once all
ldev references have been returned.
Already in flight online-verify requests or replies may still come in,
which we then need to ignore.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: don't count sendpage()d pages only referenced by tcp as in use

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Adding support for BIO/Request flags: REQ_FUA, REQ_FLUSH and REQ_DISCARD

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: drbd_md_sync before calling user space helpers

Just in case we have some pending meta data changes to sync, do it
before we call our userland helper, as that may take some time,
or even cause a hard reboot.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: fix race on meta-data update, addendum

addendum to baa33ae4eaa4477b60af7c434c0ddd1d182c1ae7

The race:
    drbd_md_sync()
if (!test_and_clear_bit(MD_DIRTY, &mdev->flags))
return;
    ==> RACE with drbd_md_mark_dirty() rearming the timer.
del_timer(&mdev->md_sync_timer);

    Fixed by moving the del_timer before the test_and_clear_bit.

Additionally only rearm the timer in drbd_md_mark_dirty, if MD_DIRTY was
not already set, reduce the grace period from five to one second, and
add an ifdef'ed debuging aid to find code paths missing an explicit
drbd_md_sync, if any, as those are the only relevant ones for this race.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Removed a race that could cause unexpected execution of w_make_resync_request()

The actual race happened int the drbd_start_resync() function. Where
drbd_resync_finished() -> __drbd_set_state() set STOP_SYNC_TIMER and
armed the timer.

If the timer fired before execution reaches the mod_timer statement
at the end of drbd_start_resync() the latter would cause an
unexpected call to w_make_resync_request().

Removed the STOP_SYNC_TIMER bit, and base it on the connection state.

The STOP_SYNC_TIMER bit probably originates probably the time before
the state engine.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: implicitly create unconfigured devices on sync-after dependencies

If pacemaker (for example) decided to initialize minor devices not in
the exact sync-after dependency order, the configuration partially
failed with an error "The sync-after minor number is invalid". (Bugz. #322)

We can avoid that by implicitly creating unconfigured minor devices,
if others depend on them.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: fix race on meta-data update

The race:
drbd_md_mark_dirty()
drbd_md_sync()
if (!test_and_clear_bit(MD_DIRTY, &mdev->flags))
return;
drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)
  ==> RACE
clear_bit(MD_DIRTY, &mdev->flags); <== spurious

Fixed by removing the spurious clear_bit.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: fix race between deconfiguring and reconfiguring network

If a drbd_nl_net_conf hits the small window between the state change
to C_STANDALONE and the corresponding cleanup in after_state_ch,
that cleanup would throw away stuff we now need again,
and later trigger BUG_ON()s.

Fixed by properly serializing the new config request with
any pending cleanup.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Disable activity log updates when the whole device is out of sync

When the complete device is marked as out of sync, we can disable
updates of the on disk AL. Currently AL updates are only disabled
if one uses the "invalidate-remote" command on an unconnected,
primary device, or when at attach time all bits in the bitmap are
set.

As of now, AL updated do not get disabled when a all bits becomes
set due to application writes to an unconnected DRBD device.
While this is a missing feature, it is not considered important,
and might get added later.

BTW, after initializing a "one legged" DRBD device
drbdadm create-md resX
drbdadm -- --force primary resX
AL updates also get disabled, until the first connect.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Actually allow BIOs up to 128k (was 32k).

Now we have multiple BIOs per ee, packets with a 32 bit length field,
it gets time to use these goodies.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: receiving of big packets, for payloads between 64kByte and 4GByte

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Sending of big packets, for payloads from 64KByte to 4GByte

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Bugfix for regression introduced with f9bc8913c06022e

If we intent to use the block_id member of an epoch entry,
we may not use the digest member.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Microfix: Assigning sector once is sufficient

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: new configuration parameter c-min-rate

We now track the data rate of locally submitted resync related requests,
and can thus detect non-resync activity on the lower level device.

If the current sync rate is above c-min-rate, and the lower level device
appears to be busy, we throttle the resyncer.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: reduce code duplication when receiving data requests

also canonicalize the return values of read_for_csum
and drbd_rs_begin_io to return -ESOMETHING, or 0 for success.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: use rolling marks for resync speed calculation

The current resync speed as displayed in /proc/drbd fluctuates a lot.
Using an array of rolling marks makes this calculation much more stable.
We used to have this (a long time ago with 0.7), but it got lost somehow.

If "stalled", do not discard the rest of the information, just add a
" (stalled)" tag to the progress line.

This patch also shortens a spinlock critical section somewhat, and
reduces the number of atomic operations in put_ldev.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: remove outdated comment and dead code

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: let drbd_free_ee implicitly free any digest

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Replaced some casts by an union. Improved comments

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Bugfix: rs_in_flight could become wrong if read_for_csum() requested reschedule later

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: The new, smarter resync speed controller

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: New sync_param packet, that includes the parameters of the new controller

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: New sync parameters for the smart resync rate controller

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: fix list corruption (recent regression)

The commit 288f422ec13667de40b278535d2a5fb5c77352c4
 drbd: Track all IO requests on the TL, not writes only
moved a list_add_tail(req, ) into a region where req
may have just been freed due to conflict detection.

Fix this by adding a proper cleanup section for that code path.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Initialize all members of sync_conf to their defaults [Bugz 315]

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Make sure tl_restart(, resend) can not get called multiple times for a new connection

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Do not try to free tl_hash in drbd_disconnect() when IO is suspended

We may not free tl_hash when IO is suspended, since we can not wait
until ap_bio_cnt reaches zero.

We can do this after susp reched 0, since then tl_clear was called

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Allow attach while IO is suspended

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Allow tl_restart() to do IO completion while IO is suspended

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Fixed a deadlock, probably only affected UP machines

After disconnect (most likely mdev->net_cnt == 0) and we are
still in an unstable state (!drbd_state_is_stable()). When we
get an IO request in drbd_get_max_buffers() (called from
__inc_ap_bio_cond(), called from inc_ap_bio()) we wake up
misc_wait. Misc_wait is also used in inc_ap_bio() to sleep
until the outcome of __inc_ap_bio_cond() changes. => Busy loop!

Solution: Have a dedicated wait queue for get_net_conf() and
put_net_conf().

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Do not do a hard state change when establishing a connection [bugz 304]

Make sure the state engine can deny two primaries to connect

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Ensure that the peer was not rebootet in the meantime before resending TL

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Delayed creation of current-UUID

When a fencing policy of "resource-and-stonith" is configured,
and DRBD looses connection to it's peer, we can delay the
creation of a new current-UUID until IO gets thawed.

That allows one to deploy fence-peer handlers that actually
commit suicide on the machine they get started.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Run the fence-peer helper asynchronously

Since we can not thaw the transfer log, the next logical step is
to allow reconnects while the fence-peer handler runs.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Reduce the verbosity of some state transitions

State transitions in the space of non-allowed states used
to be very noisy. Reduce that, since that has little value
for the majority of the user base.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Removing a by now obsolete clause in the state sanitizing

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Now we need to handle the ed_uuid of an diskless, unconnected primary correctly

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Disabled the crashed_primary detection for re-attach of last data while IO is frozen

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Do not allow a fencing-policy of resource-and-stonith with protocol A

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Finished the "on-no-data-accessible suspend-io;" functionality

When no data is accessible (no connection to the peer, nor a local disk)
allow the user to select to freeze all IO operations instead of getting
IO errors.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Removed redundant error checks in the request code path

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: factored drbd_req_make_private_bio() out of drbd_req_new()

Preparing tl_thaw_dio()

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Do not send two barriers without any writes between them

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: factored tl_restart() out of tl_clear().

If IO was frozen for a temporal network outage, resend the
content of the transfer-log into the newly established connection.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: mod_req has now a return value

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: Track all IO requests on the TL, not writes only

With that the drbd_fail_pending_reads() function becomes obsolete.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drbd: renamed drbd_tl_epoch.n_req to drbd_tl_epoch.n_writes

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

amiga floppy: Compile failure fixes

o Compile fixes for amiga floppy driver.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

atari floppy: Stop sharing request queue across multiple gendisks

o Use one request queue per gendisk instead of sharing the queue.

o Don't have hardware. No compile testing or run time testing done. Completely
  untested.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

amiga floppy: Stop sharing request queue across multiple gendisks

o Use one request queue per gendisk instead of sharing request queue

o Don't have hardware. No compile testing or run time testing done. Completely
  untested.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

floppy: switch to one queue per drive instead of sharing a queue

Pretty straight forward conversion. Note that we do round-robin
between the drives that have available requests, before we simply
used the drive that the IO scheduler told us to. Since the IO
scheduler doesn't care about multiple devices per queue, the resulting
sort would not have made sense.

Fixed by Vivek to get rid of a double lock problem in set_next_request()

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>

cciss: remove some superfluous tests from cciss_bigpassthru()

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_big_passthru

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_passthru

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_getluninfo

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_getdrivver

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_getfirmver

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_getbustypes

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_getheartbeat

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_setnodename

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_getnodename

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_setintinfo

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_getintinfo

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

cciss: factor out cciss_getpciinfo

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

loop: add some basic read-only sysfs attributes

Create /sys/block/loopX/loop directory and provide these attributes:
 - backing_file
 - autoclear
 - offset
 - sizelimit

This loop directory is present only if loop device is configured.

To be used in util-linux-ng (and possibly elsewhere like udev rules)
where code need to get loop attributes from kernel (and not store
duplicate info in userspace).

Moreover loop ioctls are not even able to provide full backing
file info because of buffer limits.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Merge branch 'radix-tree' of git://git./linux/kernel/git/dgc/xfsdev

* 'radix-tree' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev:
  radix-tree: radix_tree_range_tag_if_tagged() can set incorrect tags
  radix-tree: clear all tags in radix_tree_node_rcu_free

Linux 2.6.36-rc2

radix-tree: radix_tree_range_tag_if_tagged() can set incorrect tags

Commit ebf8aa44beed48cd17893a83d92a4403e5f9d9e2 ("radix-tree:
omplement function radix_tree_range_tag_if_tagged") does not safely
set tags on on intermediate tree nodes. The code walks down the tree
setting tags before it has fully resolved the path to the leaf under
the assumption there will be a leaf slot with the tag set in the
range it is searching.

Unfortunately, this is not a valid assumption - we can abort after
setting a tag on an intermediate node if we overrun the number of
tags we are allowed to set in a batch, or stop scanning because we
we have passed the last scan index before we reach a leaf slot with
the tag we are searching for set.

As a result, we can leave the function with tags set on intemediate
nodes which can be tripped over later by tag-based lookups. The
result of these stale tags is that lookup may end prematurely or
livelock because the lookup cannot make progress.

The fix for the problem involves reocrding the traversal path we
take to the leaf nodes, and only propagating the tags back up the
tree once the tag is set in the leaf node slot. We are already
recording the path for efficient traversal, so there is no
additional overhead to do the intermediately node tag setting in
this manner.

This fixes a radix tree lookup livelock triggered by the new
writeback sync livelock avoidance code introduced in commit
f446daaea9d4a420d16c606f755f3689dcb2d0ce ("mm: implement writeback
livelock avoidance using page tagging").

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Acked-by: Jan Kara <jack@suse.cz>

radix-tree: clear all tags in radix_tree_node_rcu_free

Commit f446daaea9d4a420d16c606f755f3689dcb2d0ce ("mm: implement
writeback livelock avoidance using page tagging") introduced a new
radix tree tag, increasing the number of tags in each node from 2 to
3. It did not, however, fix up the code in
radix_tree_node_rcu_free() that cleans up after radix_tree_shrink()
and hence could leave stray tags set in the new tag array.

The result is that the livelock avoidance code added in the the
above commit would hit stale tags when doing tag based lookups,
resulting in livelocks when trying to traverse the tree.

Fix this problem in radix_tree_node_rcu_free() so it doesn't happen
again in the future by using a loop to walk all the tags up to
RADIX_TREE_MAX_TAGS to clear the stray tags radix_tree_shrink()
leaves behind.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Acked-by: Nick Piggin <npiggin@kernel.dk>
Acked-by: Jan Kara <jack@suse.cz>

Merge branch 'kvm-updates/2.6.36' of git://git./virt/kvm/kvm

* 'kvm-updates/2.6.36' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: PIT: free irq source id in handling error path
  KVM: destroy workqueue on kvm_create_pit() failures
  KVM: fix poison overwritten caused by using wrong xstate size

Merge branch 'for-linus' of git://git./linux/kernel/git/anholt/drm-intel

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel: (58 commits)
  drm/i915,intel_agp: Add support for Sandybridge D0
  drm/i915: fix render pipe control notify on sandybridge
  agp/intel: set 40-bit dma mask on Sandybridge
  drm/i915: Remove the conflicting BUG_ON()
  drm/i915/suspend: s/IS_IRONLAKE/HAS_PCH_SPLIT/
  drm/i915/suspend: Flush register writes before busy-waiting.
  i915: disable DAC on Ironlake also when doing CRT load detection.
  drm/i915: wait for actual vblank, not just 20ms
  drm/i915: make sure eDP PLL is enabled at the right time
  drm/i915: fix VGA plane disable for Ironlake+
  drm/i915: eDP mode set sequence corrections
  drm/i915: add panel reset workaround
  drm/i915: Enable RC6 on Ironlake.
  drm/i915/sdvo: Only set is_lvds if we have a valid fixed mode.
  drm/i915: Set up a render context on Ironlake
  drm/i915 invalidate indirect state pointers at end of ring exec
  drm/i915: Wake-up wait_request() from elapsed hang-check (v2)
  drm/i915: Apply i830 errata for cursor alignment
  drm/i915: Only update i845/i865 CURBASE when disabled (v2)
  drm/i915: FBC is updated within set_base() so remove second call in mode_set()
  ...

Merge branch 'for-linus' of git://git./linux/kernel/git/penberg/slab-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slab: fix object alignment
  slub: add missing __percpu markup in mm/slub_def.h

Merge branch 'for-linus' of git://git./linux/kernel/git/ryusuke/nilfs2

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
  nilfs2: wait for discard to finish

drm/i915,intel_agp: Add support for Sandybridge D0

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drm/i915: fix render pipe control notify on sandybridge

This one is missed in last pipe control fix for sandybridge,
that really unmask interrupt bit for notify in render engine IMR.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

agp/intel: set 40-bit dma mask on Sandybridge

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drm/i915: Remove the conflicting BUG_ON()

We now attempt to free "active" objects following a GPU hang as either
the GPU will be reset or the hang is permenant. In either case, the GPU
writes will not be flushed to main memory and it should be safe to
return that memory back to the system.

The BUG_ON(active) is thus overkill and can erroneously fire after a
EIO.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>

drm/i915/suspend: s/IS_IRONLAKE/HAS_PCH_SPLIT/

For the shared paths on the next generation chipsets.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>

drm/i915/suspend: Flush register writes before busy-waiting.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>

i915: disable DAC on Ironlake also when doing CRT load detection.

Like on Sandybridge, disabling the DAC here when doing CRT load detect
avoids forever hangs waiting on the hardware.

test procedure on HP 2740p:
boot with no VGA plugged in, start X,
plug in VGA monitor (1280x1024)
chvt 3
machine hangs waiting forever.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drm/i915: wait for actual vblank, not just 20ms

Waiting for a hard coded 20ms isn't always enough to make sure a vblank
period has actually occurred, so add code to make sure we really have
passed through a vblank period (or that the pipe is off when disabling).

This prevents problems with mode setting and link training, and seems to
fix a bug like https://bugs.freedesktop.org/show_bug.cgi?id=29278, but
on an HP 8440p instead.  Hopefully also fixes
https://bugs.freedesktop.org/show_bug.cgi?id=29141.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>

workqueue: Add basic tracepoints to track workqueue execution

With the introduction of the new unified work queue thread pools,
we lost one feature: It's no longer possible to know which worker
is causing the CPU to wake out of idle. The result is that PowerTOP
now reports a lot of "kworker/a:b" instead of more readable results.

This patch adds a pair of tracepoints to the new workqueue code,
similar in style to the timer/hrtimer tracepoints.

With this pair of tracepoints, the next PowerTOP can correctly
report which work item caused the wakeup (and how long it took):

Interrupt (43)            i915      time   3.51ms    wakeups 141
Work      ieee80211_iface_work      time   0.81ms    wakeups  29
Work              do_dbs_timer      time   0.55ms    wakeups  24
Process                   Xorg      time  21.36ms    wakeups   4
Timer    sched_rt_period_timer      time   0.01ms    wakeups   1

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge git://git.infradead.org/mtd-2.6

* git://git.infradead.org/mtd-2.6:
  mtd: nand: Fix probe of Samsung NAND chips
  mtd: nand: Fix regression in BBM detection
  pxa3xx: fix ns2cycle equation

Replace Configure with Enable in description of MAXSMP

The "Configure" word tends to make user believe they have to say 'yes'
to be able to choose the number of procs/nodes.  "Enable" should be
unambiguous enough.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: make stack guard page logic use vm_prev pointer

Like the mlock() change previously, this makes the stack guard check
code use vma->vm_prev to see what the mapping below the current stack
is, rather than have to look it up with find_vma().

Also, accept an abutting stack segment, since that happens naturally if
you split the stack with mlock or mprotect.

Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: make the mlock() stack guard page checks stricter

If we've split the stack vma, only the lowest one has the guard page.
Now that we have a doubly linked list of vma's, checking this is trivial.

Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: make the vma list be doubly linked

It's a really simple list, and several of the users want to go backwards
in it to find the previous vma.  So rather than have to look up the
previous entry with 'find_vma_prev()' or something similar, just make it
doubly linked instead.

Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mtd: nand: Fix probe of Samsung NAND chips

Apparently, the check for a 6-byte ID string introduced by commit
426c457a3216fac74e3d44dd39729b0689f4c7ab ("mtd: nand: extend NAND flash
detection to new MLC chips") is NOT sufficient to determine whether or
not a Samsung chip uses their new MLC detection scheme or the old,
standard scheme. This adds a condition to check cell type.

Signed-off-by: Tilman Sauerbeck <tilman@code-monkey.de>
Signed-off-by: Brian Norris <norris@broadcom.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org

Merge branch 'x86-fixes-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, apic: Fix apic=debug boot crash
  x86, hotplug: Serialize CPU hotplug to avoid bringup concurrency issues
  x86-32: Fix dummy trampoline-related inline stubs
  x86-32: Separate 1:1 pagetables from swapper_pg_dir
  x86, cpu: Fix regression in AMD errata checking code

Documentation: fix ozlabs.org mailing list address

This list moved to lists.ozlabs.org quite some time ago.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS: Fix ozlabs.org mailing list addresses

All these lists moved to lists.ozlabs.org quite a while ago.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>