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History log of /drivers/block/aoe/aoe.h
Revision Date Author Comments
feb261e2ee5d782c7e9c71fe1ef0828244a42cc1 13-Aug-2013 Kent Overstreet <kmo@daterainc.com> aoe: Convert to immutable biovecs

Now that we've got a mechanism for immutable biovecs -
bi_iter.bi_bvec_done - we need to convert drivers to use primitives that
respect it instead of using the bvec array directly.

The aoe code no longer has to manually iterate over partial bvecs, so
some struct members go away - other struct members are effectively
renamed:

buf->resid -> buf->iter.bi_size
buf->sector -> buf->iter.bi_sector

f->bcnt -> f->iter.bi_size
f->lba -> f->iter.bi_sector

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
896dcd9a64a86d8792302615ee8ab118dc8afd9c 11-Sep-2013 Ed Cashin <ecashin@coraid.com> aoe: update internal version number to 85

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
e8866cf2b90f3a29859d2113c0fd23daf189c282 11-Sep-2013 Ed Cashin <ecashin@coraid.com> aoe: add AoE-target files to debugfs

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
94ac11833fc46fcde6eec7d97893a44c7673967b 04-Jul-2013 Ed Cashin <ecashin@coraid.com> aoe: update internal version number to v83

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ca47bbd93c1cc75b9b2736b0ac49129718f32342 04-Jul-2013 Ed Cashin <ecashin@coraid.com> aoe: update copyright date

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
8030d34397e066deecb5ee9d17387fa767b12de2 04-Jul-2013 Ed Cashin <ecashin@coraid.com> aoe: perform I/O completions in parallel

Some users have a large AoE target while others like to use many AoE
targets at the same time. In the latter case, there is an opportunity to
greatly improve aggregate throughput by allowing different threads to
complete the I/O associated with each target. For 36 targets, 4 KiB read
throughput roughly doubles, for example, with these changes in place.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2b37c7d865121249f2dee9ae25d524333b07be63 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: update internal version number to 81

This version number is printed to the console on module initialization
and is available in sysfs, which is where the userland aoe-version tool
looks for it.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
4a6c9ee93cd03604bd0e61066ce6aaf4bc0f1eb9 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: allow comma separator in aoe_iflist value

By default, the aoe driver uses any ethernet interface for AoE, but the
aoe_iflist module parameter provides a convenient way to limit AoE
traffic to a specific list of local network interfaces.

This change allows a list to be specified using the comma character as a
separator. For example,

modprobe aoe aoe_iflist=eth2,eth3

Before, it was inconvenient to get the quoting right in shell scripts
when setting aoe_iflist to have more than one network interface.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
71114ec45f09eb6ef6f9d41c98d4ab6455086e58 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: use dynamic number of remote ports for AoE storage target

Many AoE targets have four or fewer network ports, but some existing
storage devices have many, and the AoE protocol sets no limit.

This patch allows the use of more than eight remote MAC addresses per AoE
target, while reducing the amount of memory used by the aoe driver in
cases where there are many AoE targets with fewer than eight MAC addresses
each.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
e52a29326462badd9ceec90a9eb2ac2a8550e02e 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: avoid races between device destruction and discovery

This change avoids a race that could result in a NULL pointer derference
following a WARNing from kobject_add_internal, "don't try to register
things with the same name in the same directory."

The problem was found with a test that forgets and discovers an
aoe device in a loop:

while test ! -r /tmp/stop; do
aoe-flush -a
aoe-discover
done

The race was between aoedev_flush taking aoedevs out of the devlist,
allowing a new discovery of the same AoE target to take place before the
driver gets around to calling sysfs_remove_group. Fixing that one
revealed another race between do_open and add_disk, and this patch avoids
that, too.

The fix required some care, because for flushing (forgetting) an aoedev,
some of the steps must be performed under lock and some must be able to
sleep. Also, for discovering a new aoedev, some steps might sleep.

The check for a bad aoedev pointer remains from a time when about half of
this patch was done, and it was possible for the
bdev->bd_disk->private_data to become corrupted. The check should be
removed eventually, but it is not expected to add significant overhead,
occurring in the aoeblk_open routine.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
bbb44e30d07fdc111e34a5ec935b57521cea9499 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: improve handling of misbehaving network paths

An AoE target can have multiple network ports used for AoE, and in the
aoe driver, those are tracked by the aoetgt struct. These changes allow
the aoe driver to handle network paths, or aoetgts, that are not working
well, compared to the others.

Paths that do not get responses despite the retransmission of AoE
commands are marked as "tainted", and non-tainted paths are preferred.

Meanwhile, the aoe driver attempts to "probe" the tainted path in the
background by issuing reads of LBA 0 that are padded out to full
(possibly jumbo-frame) size. If the probes get responses, then the path
is "redeemed", and its taint is removed.

This mechanism has been shown to be helpful in transparently handling
and recovering from real-world network "brown outs" in ways that the
earlier "shoot the help-needing target in the head" mechanism could not.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
72837600ee8b0d09618f7fcbe36aab08c3ba8890 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: cleanup: correct comment for aoetgt nout

A misplaced comment was attached to the nout member of the aoetgt. This
change corrects the comment.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
519b77b0320fabb07fe54a300876dfff5f96d233 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: update driver-internal version to 64+

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
3fc9b032489d365957ce531d32e225b2d0b3ed11 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: commands in retransmit queue use new destination on failure

When one remote MAC address isn't working as a destination for AoE
commands, the frames used to track information associated with the AoE
commands are moved to a new aoetgt (defined by the tuple of {AoE major,
AoE minor, target MAC address}).

This patch makes sure that the frames on the queue for retransmits that
need to be done are updated to use the new destination, so that
retransmits will be sent through a working network path.

Without this change, packets on the retransmit queue will be needlessly
retransmitted to the unresponsive destination MAC, possibly causing
premature target failure before there's time for the retransmit timer to
run again, decide to retransmit again, and finally update the destination
to a working MAC address on the AoE target.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
5f0c9c48e7265039c3f945aaf44a1c6ae8adbd01 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: use high-resolution RTTs with fallback to low-res

These changes improve the accuracy of the decision about whether it's time
to retransmit an AoE command by using the microsecond-resolution
gettimeofday instead of jiffies.

Because the system time can jump suddenly, the decision reverts to using
jiffies if the high-resolution time difference is relatively large.
Otherwise the AoE targets could be considered failed inappropriately.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
3a0c40d2d29e476ece583540e4f11276e0f36d5f 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: improve network congestion handling

The aoe driver already had some congestion handling, but it was limited in
its ability to cope with the kind of congestion that can arise on more
complex networks such as those involving paths through multiple ethernet
switches.

Some of the lessons from TCP's history of development can be applied to
improving the congestion control and avoidance on AoE storage networks.
These changes use familar concepts from Van Jacobson's "Congestion
Avoidance and Control" paper from '88, without adding significant
overhead.

This patch depends on an upcoming patch that covers the failover case when
AoE commands being retransmitted are transferred from one retransmit queue
to another. Another upcoming patch increases the timing accuracy.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
667be1e757f5684576d01d7402907a2489b1402f 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: provide ATA identify device content to user on request

Make the aoe driver follow expected behavior when the user uses ioctl to
get the ATA device identify information, allowing access to model, serial
number, etc.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cd220bf51f94e6b3f7678183b6ea911cefbf7d03 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: update driver-internal version number to 60

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
a04b41cd2c3ea39115a2d4f264773a5956a3318d 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: whitespace cleanup

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1b8a1636ceea573b1d452a1cccf01c990d8d628a 18-Dec-2012 Ed Cashin <ecashin@coraid.com> aoe: update cap on outstanding commands based on config query response

The ATA over Ethernet config query response contains a "buffer count"
field reflecting the AoE target's capacity to buffer incoming AoE
commands.

By taking the current value of this field into accound, we increase
performance throughput or avoid network congestion, when the value
has increased or decreased, respectively.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
322c9ec009fdc2bc9ccb8f55afab3f7ab8ac71ab 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: update aoe-internal version number to 50

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1ac9e602625817b0c16cc70ea496875f7bd58a4d 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: remove unused code

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7159e969d1963f19e7550aafd234b0c5361e5d69 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: update and specify AoE address guards and error messages

In general, specific is better when it comes to messages about AoE usage
problems. Also, explicit checks for the AoE broadcast addresses are
added.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
0c966214589b9767fd8771b71328f83bac58cb25 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: support more AoE addresses with dynamic block device minor numbers

The ATA over Ethernet protocol uses a major (shelf) and minor (slot)
address to identify a particular storage target. These changes remove an
artificial limitation the aoe driver imposes on the use of AoE addresses.
For example, without these changes, the slot address has a maximum of 15,
but users commonly use slot numbers much greater than that.

The AoE shelf and slot address space is often used sparsely. Instead of
using a static mapping between AoE addresses and the block device minor
number, the block device minor numbers are now allocated on demand.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fea05a26c3a215796b7a4fa5cbc25278d3e16d30 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: update copyright year in touched files

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7392fbe5ade3b28387bb467e39f5f3e01f6c9f13 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: update internal version number to 49

The internal version number of the aoe driver appears in a console message
when the driver loads and is usually obtained by the user with the
userland aoe-version tool, part of the aoetools.[1]

Although this patchset includes bugfixes backported from higher-numbered
versions published on the coraid.com website, it is a form of version 49.

1. http://aoetools.sourceforge.net/

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
b21faa25c6d25a76c09f1e05a1b18ee2372e3841 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: remove unused code and add cosmetic improvements

This change removes some unused code and attempts to increase code
consistency.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
64a80f5ac78a289f66c373ace61973205d960ee7 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: associate frames with the AoE storage target

In the driver code, "target" and aoetgt refer to a particular remote
interface on the AoE storage target. The latter is identified by its AoE
major and minor addresses. Commands that are being sent to an AoE storage
target {major, minor} can be sent or retransmitted to any of the remote
MAC addresses associated with the AoE storage target.

That is, frames are naturally associated with not an aoetgt (AoE major,
AoE minor, remote MAC address) but an aoedev (AoE major, AoE minor).
Making the code reflect that reality simplifies the driver, especially
when the path to a remote MAC address becomes unusable.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
d54d35ac6605161a593e3f4411de338ef81b5263 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: failover remote interface based on aoe_deadsecs parameter

The aoe_deadsecs module parameter allows the user to specify a hard limit
on the number of seconds an AoE command can be retransmitted before the
AoE block device is considered to have failed.

Using aoe_deadsecs to determine the time we try using a different remote
interface helps to ensure that the hard limit is not reached before we've
tried to recover by sending to a different remote port.

As a data storage target, the AoE target is unambiguously identified by
its {major, minor} AoE address tuple, and an AoE target can have multiple
MAC addresses. However, note that "target" in the driver code and
comments means a {major, minor, MAC address} tuple, as in "somewhere to
send packets".

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
3f0f0133747368fe0fcf3908f788b53591bff4e0 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: use packets that work with the smallest-MTU local interface

Users with several network interfaces dedicated to AoE generally do not
configure them to support different-sized AoE data payloads on purpose.

For a given AoE target, there will be a set of local network interfaces
that can reach it. Using only the payload that will fit in the
smallest-sized MTU of all those local interfaces greatly simplifies the
driver, especially in failure scenarios.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
eb086ec59667df5b07d58176e21a5f523ead1d66 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: use a kernel thread for transmissions

The dev_queue_xmit function needs to have interrupts enabled, so the most
simple way to get the locking right but still fulfill that requirement is
to use a process that can call dev_queue_xmit serially over queued
transmissions.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
69cf2d85de773d998798e47e3335b85e5645d157 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: become I/O request queue handler for increased user control

To allow users to choose an elevator algorithm for their particular
workloads, change from a make_request-style driver to an
I/O-request-queue-handler-style driver.

We have to do a couple of things that might be surprising. We manipulate
the page _count directly on the assumption that we still have no guarantee
that users of the block layer are prohibited from submitting bios
containing pages with zero reference counts.[1] If such a prohibition now
exists, I can get rid of the _count manipulation.

Just as before this patch, we still keep track of the sk_buffs that the
network layer still hasn't finished yet and cap the resources we use with
a "pool" of skbs.[2]

Now that the block layer maintains the disk stats, the aoe driver's
diskstats function can go away.

1. https://lkml.org/lkml/2007/3/1/374
2. https://lkml.org/lkml/2007/7/6/241

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
896831f5909e2733c13c9cb13a1a215f10c3eaa8 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: kernel thread handles I/O completions for simple locking

Make the frames the aoe driver uses to track the relationship between bios
and packets more flexible and detached, so that they can be passed to an
"aoe_ktio" thread for completion of I/O.

The frames are handled much like skbs, with a capped amount of
preallocation so that real-world use cases are likely to run smoothly and
degenerate gracefully even under memory pressure.

Decoupling I/O completion from the receive path and serializing it in a
process makes it easier to think about the correctness of the locking in
the driver, especially in the case of a remote MAC address becoming
unusable.

[dan.carpenter@oracle.com: cleanup an allocation a bit]
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
3d5b06051cd5fa82c9a4285f7ce8650a0f0845ff 05-Oct-2012 Ed Cashin <ecashin@coraid.com> aoe: for performance support larger packet payloads

tAdd adds the ability to work with large packets composed of a number of
segments, using the scatter gather feature of the block layer (biovecs)
and the network layer (skb frag array). The motivation is the performance
gained by using a packet data payload greater than a page size and by
using the network card's scatter gather feature.

Users of the out-of-tree aoe driver already had these changes, but since
early 2011, they have complained of increased memory utilization and
higher CPU utilization during heavy writes.[1] The commit below appears
related, as it disables scatter gather on non-IP protocols inside the
harmonize_features function, even when the NIC supports sg.

commit f01a5236bd4b140198fbcc550f085e8361fd73fa
Author: Jesse Gross <jesse@nicira.com>
Date: Sun Jan 9 06:23:31 2011 +0000

net offloading: Generalize netif_get_vlan_features().

With that regression in place, transmits always linearize sg AoE packets,
but in-kernel users did not have this patch. Before 2.6.38, though, these
changes were working to allow sg to increase performance.

1. http://www.spinics.net/lists/linux-mm/msg15184.html

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7135a71b19be1faf48b7148d77844d03bc0717d6 09-Sep-2009 Ed Cashin <ecashin@coraid.com> aoe: allocate unused request_queue for sysfs

Andy Whitcroft reported an oops in aoe triggered by use of an
incorrectly initialised request_queue object:

[ 2645.959090] kobject '<NULL>' (ffff880059ca22c0): tried to add
an uninitialized object, something is seriously wrong.
[ 2645.959104] Pid: 6, comm: events/0 Not tainted 2.6.31-5-generic #24-Ubuntu
[ 2645.959107] Call Trace:
[ 2645.959139] [<ffffffff8126ca2f>] kobject_add+0x5f/0x70
[ 2645.959151] [<ffffffff8125b4ab>] blk_register_queue+0x8b/0xf0
[ 2645.959155] [<ffffffff8126043f>] add_disk+0x8f/0x160
[ 2645.959161] [<ffffffffa01673c4>] aoeblk_gdalloc+0x164/0x1c0 [aoe]

The request queue of an aoe device is not used but can be allocated in
code that does not sleep.

Bruno bisected this regression down to

cd43e26f071524647e660706b784ebcbefbd2e44

block: Expose stacked device queues in sysfs

"This seems to generate /sys/block/$device/queue and its contents for
everyone who is using queues, not just for those queues that have a
non-NULL queue->request_fn."

Addresses http://bugs.launchpad.net/bugs/410198
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13942

Note that embedding a queue inside another object has always been
an illegal construct, since the queues are reference counted and
must persist until the last reference is dropped. So aoe was
always buggy in this respect (Jens).

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Bruno Premont <bonbons@linux-vserver.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
b6d6c5175809934e04a606d9193ef04924a7a7d9 18-Feb-2009 Ed Cashin <ecashin@coraid.com> aoe: ignore vendor extension AoE responses

The Welland ME-747K-SI AoE target generates unsolicited AoE responses that
are marked as vendor extensions. Instead of ignoring these packets, the
aoe driver was generating kernel messages for each unrecognized response
received. This patch corrects the behavior.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Reported-by: <karaluh@karaluh.pl>
Tested-by: <karaluh@karaluh.pl>
Cc: <stable@kernel.org>
Cc: Alex Buell <alex.buell@munted.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
411c41eea58bd3500cf897e2c27dd5330935a3a8 25-Nov-2008 Harvey Harrison <harvey.harrison@gmail.com> aoe: remove private mac address format function

Add %pm to omit the colons when printing a mac address.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
e9bb8fb0b6d61a822201537b25206a0ca34b9d1d 22-Sep-2008 David S. Miller <davem@davemloft.net> aoe: Use SKB interfaces for list management instead of home-grown stuff.

Signed-off-by: David S. Miller <davem@davemloft.net>
0302190411c2ba79819303503999cc839d600704 29-Apr-2008 Adrian Bunk <bunk@kernel.org> remove aoedev_isbusy()

Remove the no longer used aoedev_isbusy().

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
52e112b3ab6b2b35a144565c8ea3bdda1e2845f2 08-Feb-2008 Ed L. Cashin <ecashin@coraid.com> aoe: update copyright date

Update the year in the copyright notices.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9bb237b6a670fa7a6af3adc65231b1f6fda44510 08-Feb-2008 Ed L. Cashin <ecashin@coraid.com> aoe: dynamically allocate a capped number of skbs when necessary

What this Patch Does

Even before this recent series of 12 patches to 2.6.22-rc4, the aoe
driver was reusing a small set of skbs that were allocated once and
were only used for outbound AoE commands.

The network layer cannot be allowed to put_page on the data that is
still associated with a bio we haven't returned to the block layer,
so the aoe driver (even before the patch under discussion) is still
the owner of skbs that have been handed to the network layer for
transmission. We need to keep track of these skbs so that we can
free them, but by tracking them, we can also easily re-use them.

The new patch was a response to the behavior of certain network
drivers. We cannot reuse an skb that the network driver still has
in its transmit ring. Network drivers can defer transmit ring
cleanup and then use the state in the skb to determine how many data
segments to clean up in its transmit ring. The tg3 driver is one
driver that behaves in this way.

When the network driver defers cleanup of its transmit ring, the aoe
driver can find itself in a situation where it would like to send an
AoE command, and the AoE target is ready for more work, but the
network driver still has all of the pre-allocated skbs. In that
case, the new patch just calls alloc_skb, as you'd expect.

We don't want to get carried away, though. We try not to do
excessive allocation in the write path, so we cap the number of skbs
we dynamically allocate.

Probably calling it a "dynamic pool" is misleading. We were already
trying to use a small fixed-size set of pre-allocated skbs before
this patch, and this patch just provides a little headroom (with a
ceiling, though) to accomodate network drivers that hang onto skbs,
by allocating when needed. The d->skbpool_hd list of allocated skbs
is necessary so that we can free them later.

We didn't notice the need for this headroom until AoE targets got
fast enough.

Alternatives

If the network layer never did a put_page on the pages in the bio's
we get from the block layer, then it would be possible for us to
hand skbs to the network layer and forget about them, allowing the
network layer to free skbs itself (and thereby calling our own
skb->destructor callback function if we needed that). In that case
we could get rid of the pre-allocated skbs and also the
d->skbpool_hd, instead just calling alloc_skb every time we wanted
to transmit a packet. The slab allocator would effectively maintain
the list of skbs.

Besides a loss of CPU cache locality, the main concern with that
approach the danger that it would increase the likelihood of
deadlock when VM is trying to free pages by writing dirty data from
the page cache through the aoe driver out to persistent storage on
an AoE device. Right now we have a situation where we have
pre-allocation that corresponds to how much we use, which seems
ideal.

Of course, there's still the separate issue of receiving the packets
that tell us that a write has successfully completed on the AoE
target. When memory is low and VM is using AoE to flush dirty data
to free up pages, it would be perfect if there were a way for us to
register a fast callback that could recognize write command
completion responses. But I don't think the current problems with
the receive side of the situation are a justification for
exacerbating the problem on the transmit side.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
262bf54144ebcb78cd0d057d2705dc5fb7bba7ac 08-Feb-2008 Ed L. Cashin <ecashin@coraid.com> aoe: user can ask driver to forget previously detected devices

When an AoE device is detected, the kernel is informed, and a new block device
is created. If the device is unused, the block device corresponding to remote
device that is no longer available may be removed from the system by telling
the aoe driver to "flush" its list of devices.

Without this patch, software like GPFS and LVM may attempt to read from AoE
devices that were discovered earlier but are no longer present, blocking until
the I/O attempt times out.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1eb0da4cea28ae8f1bbe61822a2cc04e6d074e03 08-Feb-2008 Ed L. Cashin <ecashin@coraid.com> aoe: mac_addr: avoid 64-bit arch compiler warnings

By returning unsigned long long, mac_addr does not generate compiler warnings
on 64-bit architectures.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
68e0d42f39d85b334d3867a4e5fc2e0e775c1a6c 08-Feb-2008 Ed L. Cashin <ecashin@coraid.com> aoe: handle multiple network paths to AoE device

A remote AoE device is something can process ATA commands and is identified by
an AoE shelf number and an AoE slot number. Such a device might have more
than one network interface, and it might be reachable by more than one local
network interface. This patch tracks the available network paths available to
each AoE device, allowing them to be used more efficiently.

Andrew Morton asked about the call to msleep_interruptible in the revalidate
function. Yes, if a signal is pending, then msleep_interruptible will not
return 0. That means we will not loop but will call aoenet_xmit with a NULL
skb, which is a noop. If the system is too low on memory or the aoe driver is
too low on frames, then the user can hit control-C to interrupt the attempt to
do a revalidate. I have added a comment to the code summarizing that.

Andrew Morton asked whether the allocation performed inside addtgt could use a
more relaxed allocation like GFP_KERNEL, but addtgt is called when the aoedev
lock has been locked with spin_lock_irqsave. It would be nice to allocate the
memory under fewer restrictions, but targets are only added when the device is
being discovered, and if the target can't be added right now, we can try again
in a minute when then next AoE config query broadcast goes out.

Andrew Morton pointed out that the "too many targets" message could be printed
for failing GFP_ATOMIC allocations. The last patch in this series makes the
messages more specific.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
8911ef4dc97f77797f297318010a7424300d2d50 08-Feb-2008 Ed L. Cashin <ecashin@coraid.com> aoe: bring driver version number to 47

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
abdbf94d7c6f1fcb2931d5cb7562a6159323b704 17-Oct-2007 Ed L. Cashin <ecashin@coraid.com> aoe: remove unecessary wrapper function

We can just use skb_mac_header now, and we don't need a wrapper function to
perform the cast. Instead of requiring the reader to check aoe.h to look
up what an aoe_hdr function does, I'd rather do without it.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
165125e1e480f9510a5ffcfbfee4e3ee38c05f23 24-Jul-2007 Jens Axboe <jens.axboe@oracle.com> [BLOCK] Get rid of request_queue_t typedef

Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
98e399f82ab3a6d863d1d4a7ea48925cc91c830e 19-Mar-2007 Arnaldo Carvalho de Melo <acme@redhat.com> [SK_BUFF]: Introduce skb_mac_header()

For the places where we need a pointer to the mac header, it is still legal to
touch skb->mac.raw directly if just adding to, subtracting from or setting it
to another layer header.

This one also converts some more cases to skb_reset_mac_header() that my
regex missed as it had no spaces before nor after '=', ugh.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
029720f15dcd3c6c16824177cfc486083b229411 10-Mar-2007 Arnaldo Carvalho de Melo <acme@redhat.com> [AOE]: Introduce aoe_hdr()

For consistency with other skb->mac.raw users.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
c4028958b6ecad064b1a6303a6a5906d4fe48d73 22-Nov-2006 David Howells <dhowells@redhat.com> WorkStruct: make allyesconfig

Fix up for make allyesconfig.

Signed-Off-By: David Howells <dhowells@redhat.com>
a12c93f08b8fc83b7fcdabaf92b1adcea7489f5e 20-Sep-2006 Ed L. Cashin <ecashin@coraid.com> aoe: revert printk macros

This patch addresses the concern that the aoe driver should
not introduce unecessary conventions that must be learned by
the reader. It reverts patch 6.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
086216db1435f44a58c18454acfa59f013510c95 20-Sep-2006 Ed L. Cashin <ecashin@coraid.com> aoe: update driver version

Update aoe driver version number to 32.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
4f51dc5e9ae195d2e8c22e5f574e004c2f6518a4 20-Sep-2006 Ed L. Cashin <ecashin@coraid.com> aoe: zero copy write 2 of 2

Avoid memory copy on writes.
(This patch follows patch 4.)

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
dced3a053dd5415a7321e1ae153c96dea644da4e 20-Sep-2006 Ed L. Cashin <ecashin@coraid.com> aoe: improve retransmission heuristics

Add a dynamic minimum timer for better retransmission behavior.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
6bb6285fdb948cedee586c6bebc9ebc5e32a5c35 20-Sep-2006 Ed L. Cashin <ecashin@coraid.com> aoe: clean up printks via macros

Use simple macros to clean up the printks.
(This patch is reverted by the 14th patch to follow.)

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
19bf26353c50bc2be375109ec73f2f0bbd616ed1 20-Sep-2006 Ed L. Cashin <ecashin@coraid.com> aoe: jumbo frame support 1 of 2

Add support for jumbo ethernet frames.
(This patch depends on patch 7 to follow.)

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
e407a7f6cd143b3ab4eb3d7e1cf882e96b710eb5 20-Sep-2006 Ed L. Cashin <ecashin@coraid.com> aoe: zero copy write 1 of 2

Avoid memory copy on writes.
(This patch depends on fixes in patch 9 to follow.)

Although skb->len should not be set when working with linear skbuffs,
the skb->tail pointer maintained by skb_put/skb_trim is not relevant
to what happens when the skb_fill_page_desc function is called. This
issue was raised without comment in linux-kernel and netdev earlier
this month:

http://thread.gmane.org/gmane.linux.kernel/446474/
http://thread.gmane.org/gmane.linux.network/45444/

So until there is something analogous to skb_put that works for
zero-copy write skbuffs, we will do what the other callers of
skb_fill_page_desc are doing.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2611464d7f36685fb1990275d3de1e72e6aff9d9 20-Sep-2006 Ed L. Cashin <ecashin@coraid.com> aoe: update copyright date

Update the copyright year to 2006.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
0fdf109676d1eda4ff8199a9a3ee3f11c555c1b3 07-Feb-2006 Ed L. Cashin <ecashin@coraid.com> [PATCH] aoe [3/3]: update version to 22

Increase version number to 22.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
a712c0efbffb09f7b837577e29d0efb043fea0ea 19-Jan-2006 Ed L. Cashin <ecashin@coraid.com> [PATCH] aoe [8/8]: update driver version number

Update aoe driver version number.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
3ae1c24e395b2b65326439622223d88d92bfa03a 19-Jan-2006 Ed L. Cashin <ecashin@coraid.com> [PATCH] aoe [2/8]: support dynamic resizing of AoE devices

Allow the driver to recognize AoE devices that have changed size.
Devices not in use are updated automatically, and devices that are in
use are updated at user request.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
3dc7c555636e46bb64b4da3570a345f4b247eaf0 29-Sep-2005 Ed L. Cashin <ecashin@coraid.com> [PATCH] aoe: update to version 14

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Update driver version number to 14.
49a1fd60d2a8e671222515cf6055e91781278517 19-Aug-2005 Ed L Cashin <ecashin@coraid.com> [PATCH] aoe [2/2]: update driver version number to twelve

Update driver version number to twelve.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
e39526e6e7a96904c9f1c85375d49ff437c18c44 19-Aug-2005 Ed L Cashin <ecashin@coraid.com> [PATCH] aoe [1/2]: support 16 AoE slot addresses per AoE shelf

Change the number of supported AoE slot addresses per AoE shelf
address to 16.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
0e57c7166675a86293f150d5ef7779edd629fe2a 29-Apr-2005 Ed L Cashin <ecashin@coraid.com> [PATCH] aoe: update version number to 10

update version number to 10

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
a4b38364093bf2094ff858ad45f490521bb87984 19-Apr-2005 ecashin@coraid.com <ecashin@coraid.com> [PATCH] aoe 12/12: send outgoing packets in order

I can't use list.h, since sk_buff doesn't have a list_head but instead
has two struct sk_buff pointers, and I want to avoid any extra memory
allocation.

send outgoing packets in order

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
0c6f0e7920f39b28bdbe5f134f3e592542332d87 19-Apr-2005 ecashin@coraid.com <ecashin@coraid.com> [PATCH] aoe 11/12: add support for disk statistics

add support for disk statistics

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
63e9cc5d6fbe8b58ea1ee96439d356cbf726fbc0 19-Apr-2005 ecashin@coraid.com <ecashin@coraid.com> [PATCH] aoe 6/12: Alexey Dobriyan sparse cleanup

Alexey Dobriyan sparse cleanup

Signed-off-by: Alexey Dobriyan <adobriyan@mail.ru>
Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
b68650fd3f31d47426a2b1c6cfad904880258423 19-Apr-2005 ecashin@coraid.com <ecashin@coraid.com> [PATCH] aoe 3/12: update driver version to 6

update driver version to 6

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
32465c650670c7499548d70fdeed57fab44ee679 19-Apr-2005 ecashin@coraid.com <ecashin@coraid.com> [PATCH] aoe 2/12: allow multiple aoe devices with same MAC

allow multiple aoe devices with same MAC addr

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
fc458dcda27c6d26cb11ef9ee9c1c3599711be94 19-Apr-2005 ecashin@coraid.com <ecashin@coraid.com> [PATCH] aoe 1/12: remove too-low cap on minor number

remove too-low cap on minor number

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 17-Apr-2005 Linus Torvalds <torvalds@ppc970.osdl.org> Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!