In the kernel we have a nice helper that may be used here. This patch
substitutes the custom implementation by the native function call.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Ed Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We should return NULL on failure instead of returning a freed pointer.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Ed Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The value returned by the static minor device number number allocator is
the real minor number, so it must be multiplied by the supported number
of partitions per aoedev.

Without this fix the support for systems without udev is incomplete, and
the few users of aoe on such systems will have surprising results when
device nodes names do not match the AoE target.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Because the minor_get and related functions use the return values for
errors, the compiler doesn't know that sysminor will always either 1) be
initialized in aoedev_by_aoeaddr by the call to minor_get, or 2) be
unused as the "goto out" is executed.

This patch avoids the compiler warning.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For some special-purpose systems where udev isn't present, static
allocation of minor numbers is desirable.  This update distinguishes
different failure scenarios, to help the user understand what went
wrong.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Users sometimes want to cause the aoe driver to forget a particular
previously discovered device when it is no longer online.  The aoetools
provide an "aoe-flush" command that users run to perform this
administrative task.  The changes below provide the support needed in the
driver.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Because udev use is so widespread, making the old static mapping the
default is too conservative, given the severe limitations it places on
usable AoE addresses.  Storage virtualization and larger shelves have made
the old limitations too confining.

These changes make the dynamic block device minor numbers the default,
removing the limitations on usable AoE addresses.

The static arrangement is still available with aoe_dyndevs=0, and the
aoe-stat tool from the userland aoetools package, the user space
counterpart to the aoe driver, recognizes the case where there is a
mismatch between the minor number in sysfs and the minor number in a
special device file.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The old mapping between AoE target shelf and slot addresses and the block
device minor number is retained as a backwards-compatible feature, with a
new "aoe_dyndevs" module parameter available for enabling dynamic block
device minor numbers.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This change eliminates the danger that the user could rmmod the driver for
a network interface that is being used for AoE by the aoe driver.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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/2007/7/6/241Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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 f01a5236
  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.htmlSigned-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

flush_scheduled_work() is deprecated and scheduled to be removed.
Directly cancel aoedev->work on free instead of depending on
flush_scheduled_works().
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

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

  cd43e26f

  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: NEd 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: NJens Axboe <jens.axboe@oracle.com>

with while (i-- > 0); i reaches -1 after the loop, so the test below is printed
one too early: 0 still means success.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move disk->capacity to part0->nr_sects and convert all users who
directly accessed the field to use {get|set}_capacity().  This is done
early to allow the __dev field to be moved.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove the no longer used aoedev_isbusy().
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I guess aoedev_init() can go away now.

Cc: Greg KH <greg@kroah.com>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Update the year in the copyright notices.
Signed-off-by: NEd L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NEd L. Cashin <ecashin@coraid.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As bi_end_io is only called once when the reqeust is complete,
the 'size' argument is now redundant.  Remove it.

Now there is no need for bio_endio to subtract the size completed
from bi_size.  So don't do that either.

While we are at it, change bi_end_io to return void.
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Fix up for make allyesconfig.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>

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: N"Ed L. Cashin" <ecashin@coraid.com>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Avoid memory copy on writes.
(This patch follows patch 4.)
Signed-off-by: N"Ed L. Cashin" <ecashin@coraid.com>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Use simple macros to clean up the printks.
(This patch is reverted by the 14th patch to follow.)
Signed-off-by: N"Ed L. Cashin" <ecashin@coraid.com>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>