The k8t_sound_hostbridge PCI quick fires on my motherboard (Jetway
K8M8MS) while it shouldn't: the on-board sound chip is not disabled
and is working just fine. Looking at the code, I see that we are
running the quirk for two distinct register values (0x88 and 0xc8)
and then clear bit 6 (0x40). However value 0x88 already has bit 6
cleared so this is a no-op. This is what happens on my board. Thus I
believe that the quirk should only be run for register value 0xc8.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

RX790 can't do MSI like its predecessors.  Disable MSI on RX790.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

RD580 can't do MSI like its predecessors.  Disable MSI on RD580.
Signed-off-by: NTejun Heo <teheo@suse.de>
CC: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

RS690 can't do MSI like its predecessors.  Disable MSI on RS690.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Henry Su <henry.su@amd.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

[PATCH] PCI: make pcie_get_readrq visible in pci.h

pcie_get_readrq() is EXPORT_SYMBOL'ed, but its prototype is not
visible in pci.h, add it there.

This is needed by some network drivers.
Signed-off-by: NBrice Goglin <brice@myri.com>
Acked-by: NPeter Oruba <peter.oruba@amd.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Adrian Bunk wrote:
> Alois Nešpor wrote
>> PCI: Bus #0b (-#0e) is hidden behind transparent bridge #0a (-#0b) (try 'pci=assign-busses')
>> Please report the result to linux-kernel to fix this permanently"
>>
>> dmesg:
>> "Yenta: Raising subordinate bus# of parent bus (#0a) from #0b to #0e"
>> without pci=assign-busses and nothing with pci=assign-busses.
> 
> Bernhard?

Ok, lets kill the message. As Alois Nešpor also saw, that's fixed up by Yenta,
so PCI does not have to warn about it. PCI could still warn about it if
is_cardbus is 0 in that instance of pci_scan_bridge(), but so far I have
not seen a report where this would have been the case so I think we can
spare the kernel of that check (removes ~300 lines of asm) unless debugging
is done.

History: The whole check was added in the days before we had the fixup
for this in Yenta and pci=assign-busses was the only way to get CardBus
cards detected on many (not all) of the machines which give this warning.

In theory, there could be cases when this warning would be triggered and
it's not cardbus, then the warning should still apply, but I think this
should only be the case when working on a completely broken PCI setup,
but one may have already enabled the debug code in drivers/pci and the
patched check would then trigger.

I do not sign this off yet because it's completely untested so far, but
everyone is free to test it (with the #ifdef DEBUG replaced by #if 1 and
pr_debug( changed to printk(.

We may also dump the whole check (remove everything within the #ifdef from
the source) if that's perferred.

On Alois Nešpor's machine this would then (only when debugging) this message:

"PCI: Bus #0b (-#0e) is partially hidden behind transparent bridge #0a (-#0b)"

"partially" should be in the message on his machine because #0b of #0b-#0e 
is reachable behind #0a-#0b, but not #0c-#0e.

But that differentiation is now moot anyway because the fixup in Yenta takes
care of it as far as I could see so far, which means that unless somebody
is debugging a totally broken PCI setup, this message is not needed anymore,
not even for debugging PCI.


Ok, here the patch with the following changes:

* Refined to say that the bus is only partially hidden when the parent
  bus numbers are not totally way off (outside of) the child bus range
* remove the reference to pci=assign-busses and the plea to report it

We could add a pure source code-only comment to keep a reference to
pci=assign-busses the in case when this is triggered by someone who
is debugging the cause of this message and looking the way to solve it.

From: Bernhard Kaindl <bk@suse.de>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

remove stale BKL use from drivers/pci/hotplug/cpqphp_ctrl.c.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This useful interface is hardly mentioned anywhere in the in-tree
documentation.
Signed-off-by: NRolf Eike Beer <eike-kernel@sf-tec.de>
Cc: Tejun Heo <htejun@gmail.com>
Acked-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

quirk_e100_interrupts() is called after PCI controller is initialized
and before PCI bus enumeration is performed. On some powerpc platforms
which modify PCI controller configuration and set different MEM and IO
windows than those set by firmware quirk_e100_interrupt() is causing
kernel panic as it tries to read from device BAR0 offets which at this
time points to a invalid PCI window (set by firmware).

This patch delays the quirk_100_interrupt() to pci_fixup_final phase,
which happens after bus enumeration and before PCI enable and
device driver initialization.
Signed-off-by: NMarian Balakowicz <m8@semihalf.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We need pci_bus_find_capability() in some arch/powerpc code so move
the prototype into a header accessible to it.

Also kill the duplicate prototype for pci_bus_alloc_resource().
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

* git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog:
  [WATCHDOG] Add support for 1533 bridge to alim1535_wdt
  [WATCHDOG] Add a 00-INDEX file to Documentation/watchdog/
  [WATCHDOG] Eurotechwdt.c - clean-up comments

* 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6:
  [SPARC32]: Revert f642b263.
  [SPARC64]: Need to clobber global reg vars in switch_to().

* 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6:
  [IRDA] irda_nl_get_mode: always results in failure
  [PPP]: Fix output buffer size in ppp_decompress_frame().
  [IRDA]: Avoid a label defined but not used warning in irda_init()
  [IPV6]: Fix kernel panic while send SCTP data with IP fragments
  [SNAP]: Check packet length before reading
  [DCCP]: Allocation in atomic context

* 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6:
  [S390] Change atomic_read/set to inline functions with barrier semantics.
  [S390] kprobes: fix instruction length calculation
  [S390] hypfs: inode corruption due to missing locking
  [S390] disassembler: fix b2 opcodes like srst, bsg, and others
  [S390] vmur: fix reference counting for vmur device structure
  [S390] vmur: fix diag14 exceptions with addresses > 2GB.
  [S390] qdio: Refresh buffer states for IQDIO Asynchronous output queue
  [S390] qdio: fix EQBS handling on CCQ96
  [S390] cio: change confusing message in cmf.
  [S390] cio: dont forget to set last slot to NULL in ccw_uevent().

Touching vmalloc memory in the middle of a lazy mode update can generate
a kernel PDE update, which must be flushed immediately.  The fix is to
leave lazy mode when doing a vmalloc sync.
Signed-off-by: NZachary Amsden <zach@vmware.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After doing some tests this seems to be the best variant for s390 and
should be correct as well. With gcc 4.2.1 we get the following kernel
image sizes using the default configuration:

atomic_t type volatile, atomic_read/set defines   5311824 bytes
atomic_t type int, atomic_read/set defines        5270864 bytes
atomic_t type int, atomic_read/set inline asm     5279056 bytes
atomic_t type int, atomic_read/set inline barrier 5270864 bytes
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Placing a kprobe on "bc" instruction (s390/s390x) can cause an oops.
The instruction length is encoded into the first two bits of the s390
instruction. Kprobe is incorrectly computing the instruction length.
The instruction length is used for determining what type of "fix-up" is
needed for conditional branch instruction. The problem can bee seen by
placing a kprobe on a "bc" instruction that will not branch. The
results is that Kprobe incorrectly computes the new instruction
pointer (psw.addr) after single stepping the instruction. The problem
is corrected with this patch.
Signed-off-by: NDavid Wilder <dwilder@us.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

hypfs removes the whole hypfs directory tree and creates a new one, when a
process triggers an update by writing to the "update" attribute. When removing
and creating files, it is necessary to lock the inode of the parent directory
where the files live. Currently hypfs does not lock the parent inode, which
can lead to inode corruption. This patch:
 * Introduces correct locking
 * Fixes i_nlink reference counting for inodes, when creating directories
 * Adds info printk, when hypfs filesystem has been mounted
Signed-off-by: NMichael Holzheu <holzheu@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

The instruction table for b2 opcodes was missing an opfrag value
for the cpya instruction. All instructions specified after cpya
were not considered by the disassembler. The fix is simple and
obvious - add the opfrag field to the cpya instruction.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

When a vmur device is removed due to a detach of the device, currently the
ur device structure is freed. Unfortunately it can happen, that there is
still a user of the device structure, when the character device is open
during the detach process. To fix this, reference counting for the vmur
structure is introduced.
In addition to that, the online, offline, probe and remove functions are
serialized now using a global mutex.
Signed-off-by: NMichael Holzheu <holzheu@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

There are several s390 diagnose calls, which must be executed below the
2GB memory boundary. In order to enforce this, those diagnoses must be
compiled into the kernel. Currently diag 14 can be called within the
vmur kernel module from addresses above 2GB. This leads to specification
exceptions. This patch moves diag10, diag14 and diag210 into the new
diag.c file.
Signed-off-by: NMichael Holzheu <holzheu@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

Hipersocket Multicast queue works asynchronously. When sending buffers,
the buffer state change may happen delayed. The tasklet for checking
changes in the outbound queue excluded IQDIO async queues from this
process. This created either a hang situation when the queue ran full,
or presented a hang situation a interface close time.
The tasklet processing is changed to include IQDIO async queues when
requesting buffer state refresh.
Signed-off-by: NKlaus D. Wacker <kdwacker@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

QDIO returned from EQBS instruction in any case after return code
CCQ=96 was issued regardless whether buffer states for at least one
buffer were extracted or not.
This caused FCP devices to hang when running under z/VM and having
QIOASSASIST=ON and having high I/O rates.
In order to fix this qdio return code processing of EQBS instruction
after CCQ=96 is changed that buffers are returned and if no buffers
where extracted the instruction is repeated at once.
Signed-off-by: NKlaus D. Wacker <kdwacker@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

cmf currently prints a message that more than 4096 channels are not
allowed in basic mode - however, this can only be enforced if cmf was
a module (which is no longer possible). It makes much more sense to
not check the specified number of channels and just print a message if
the block for basic mode could not be allocated (which may happen for
any number of specified channels).
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

It seems an extraneous trailing ';' has slipped in to the error handling for a
name registration failure causing the error path to trigger unconditionally.
Signed-off-by: NAndy Whitcroft <apw@shadowen.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NSamuel Ortiz <samuel@sortiz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch addresses the issue with "osize too small" errors in mppe
encryption.  The patch fixes the issue with wrong output buffer size
being passed to ppp decompression routine.

--------------------
As pointed out by Suresh Mahalingam, the issue addressed by
ppp-fix-osize-too-small-errors-when-decoding patch is not fully resolved yet.
The size of allocated output buffer is correct, however it size passed to
ppp->rcomp->decompress in ppp_generic.c if wrong. The patch fixes that.
--------------------
Signed-off-by: NKonstantin Sharlaimov <konstantin.sharlaimov@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Easily avoidable compiler warnings bug me.

Building irmod without CONFIG_SYSCTL currently results in :
 net/irda/irmod.c:132: warning: label 'out_err_2' defined but not used

But that can easily be avoided by simply moving the label inside
the existing "#ifdef CONFIG_SYSCTL" one line above it.

This patch moves the label and buys us one less warning with no
ill effects.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If ICMP6 message with "Packet Too Big" is received after send SCTP DATA,
kernel panic will occur when SCTP DATA is send again.

This is because of a bad dest address when call to skb_copy_bits().

The messages sequence is like this:

Endpoint A                             Endpoint B
                               <-------  SCTP DATA (size=1432)
ICMP6 message ------->
(Packet Too Big pmtu=1280)
                               <-------  Resend SCTP DATA (size=1432)
------------kernel panic---------------

 printing eip:
c05be62a
*pde = 00000000
Oops: 0002 [#1]
SMP
Modules linked in: scomm l2cap bluetooth ipv6 dm_mirror dm_mod video output sbs battery lp floppy sg i2c_piix4 i2c_core pcnet32 mii button ac parport_pc parport ide_cd cdrom serio_raw mptspi mptscsih mptbase scsi_transport_spi sd_mod scsi_mod ext3 jbd ehci_hcd ohci_hcd uhci_hcd
CPU:    0
EIP:    0060:[<c05be62a>]    Not tainted VLI
EFLAGS: 00010282   (2.6.23-rc2 #1)
EIP is at skb_copy_bits+0x4f/0x1ef
eax: 000004d0   ebx: ce12a980   ecx: 00000134   edx: cfd5a880
esi: c8246858   edi: 00000000   ebp: c0759b14   esp: c0759adc
ds: 007b   es: 007b   fs: 00d8  gs: 0000  ss: 0068
Process swapper (pid: 0, ti=c0759000 task=c06d0340 task.ti=c0713000)
Stack: c0759b88 c0405867 ce12a980 c8bff838 c789c084 00000000 00000028 cfd5a880
       d09f1890 000005dc 0000007b ce12a980 cfd5a880 c8bff838 c0759b88 d09bc521
       000004d0 fffff96c 00000200 00000100 c0759b50 cfd5a880 00000246 c0759bd4
Call Trace:
 [<c0405e1d>] show_trace_log_lvl+0x1a/0x2f
 [<c0405ecd>] show_stack_log_lvl+0x9b/0xa3
 [<c040608d>] show_registers+0x1b8/0x289
 [<c0406271>] die+0x113/0x246
 [<c0625dbc>] do_page_fault+0x4ad/0x57e
 [<c0624642>] error_code+0x72/0x78
 [<d09bc521>] ip6_output+0x8e5/0xab2 [ipv6]
 [<d09bcec1>] ip6_xmit+0x2ea/0x3a3 [ipv6]
 [<d0a3f2ca>] sctp_v6_xmit+0x248/0x253 [sctp]
 [<d0a3c934>] sctp_packet_transmit+0x53f/0x5ae [sctp]
 [<d0a34bf8>] sctp_outq_flush+0x555/0x587 [sctp]
 [<d0a34d3c>] sctp_retransmit+0xf8/0x10f [sctp]
 [<d0a3d183>] sctp_icmp_frag_needed+0x57/0x5b [sctp]
 [<d0a3ece2>] sctp_v6_err+0xcd/0x148 [sctp]
 [<d09cf1ce>] icmpv6_notify+0xe6/0x167 [ipv6]
 [<d09d009a>] icmpv6_rcv+0x7d7/0x849 [ipv6]
 [<d09be240>] ip6_input+0x1dc/0x310 [ipv6]
 [<d09be965>] ipv6_rcv+0x294/0x2df [ipv6]
 [<c05c3789>] netif_receive_skb+0x2d2/0x335
 [<c05c5733>] process_backlog+0x7f/0xd0
 [<c05c58f6>] net_rx_action+0x96/0x17e
 [<c042e722>] __do_softirq+0x64/0xcd
 [<c0406f37>] do_softirq+0x5c/0xac
 =======================
Code: 00 00 29 ca 89 d0 2b 45 e0 89 55 ec 85 c0 7e 35 39 45 08 8b 55 e4 0f 4e 45 08 8b 75 e0 8b 7d dc 89 c1 c1 e9 02 03 b2 a0 00 00 00 <f3> a5 89 c1 83 e1 03 74 02 f3 a4 29 45 08 0f 84 7b 01 00 00 01
EIP: [<c05be62a>] skb_copy_bits+0x4f/0x1ef SS:ESP 0068:c0759adc
Kernel panic - not syncing: Fatal exception in interrupt

Arnaldo says:
====================
Thanks! I'm to blame for this one, problem was introduced in:

b0e380b1

@@ -761,7 +762,7 @@ slow_path:
                /*
                 *      Copy a block of the IP datagram.
                 */
-               if (skb_copy_bits(skb, ptr, frag->h.raw, len))
+               if (skb_copy_bits(skb, ptr, skb_transport_header(skb),
len))
                        BUG();
                left -= len;
====================
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The snap_rcv code reads 5 bytes so we should make sure that
we have 5 bytes in the head before proceeding.

Based on diagnosis and fix by Evgeniy Polyakov, reported by
Alan J. Wylie.

Patch also kills the skb->sk assignment before kfree_skb
since it's redundant.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fixes the following bug reported in syslog:

[ 4039.051658] BUG: sleeping function called from invalid context at /usr/src/davem-2.6/mm/slab.c:3032
[ 4039.051668] in_atomic():1, irqs_disabled():0
[ 4039.051670] INFO: lockdep is turned off.
[ 4039.051674]  [<c0104c0f>] show_trace_log_lvl+0x1a/0x30
[ 4039.051687]  [<c0104d4d>] show_trace+0x12/0x14
[ 4039.051691]  [<c0104d65>] dump_stack+0x16/0x18
[ 4039.051695]  [<c011371e>] __might_sleep+0xaf/0xbe
[ 4039.051700]  [<c0157b66>] __kmalloc+0xb1/0xd0
[ 4039.051706]  [<f090416f>] ccid2_hc_tx_alloc_seq+0x35/0xc3 [dccp_ccid2]
[ 4039.051717]  [<f09048d6>] ccid2_hc_tx_packet_sent+0x27f/0x2d9 [dccp_ccid2]
[ 4039.051723]  [<f085486b>] dccp_write_xmit+0x1eb/0x338 [dccp]
[ 4039.051741]  [<f085603d>] dccp_sendmsg+0x113/0x18f [dccp]
[ 4039.051750]  [<c03907fc>] inet_sendmsg+0x2e/0x4c
[ 4039.051758]  [<c033a47d>] sock_aio_write+0xd5/0x107
[ 4039.051766]  [<c015abc1>] do_sync_write+0xcd/0x11c
[ 4039.051772]  [<c015b296>] vfs_write+0x118/0x11f
[ 4039.051840]  [<c015b932>] sys_write+0x3d/0x64
[ 4039.051845]  [<c0103e7c>] syscall_call+0x7/0xb
[ 4039.051848]  =======================

The problem was that GFP_KERNEL was used; fixed by using gfp_any().
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Gerd Hoffmann pointed out that my patch from yesterday can lead
to a null pointer dereference if the kernel is booted with no
console, and no earlyprintk defined. This fixes that issue.
Signed-off-by: NRobin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The initial user manuals for MPC8544/8533 had some issues with properly
documenting the device IDs for MPC8544/8533.  These processors are almost
identical and both show up on the reference boards.

Fix up the quirks for PCIe support to handle MPC8533/E.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

There are special PHY settings available on Yukon EC-U chip that
should not get cleared. This should solve mysterious errors on some
motherboards (like Gigabyte DS-3).
Signed-off-by: NStephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes handling of USB ISO completion error -EXDEV and includes
several other changes to current CVS version at isdn4linux.de (changes
in debug flags, style of code remarks, etc)
Signed-off-by: NMartin Bachem <info@colognechip.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I did some testing and found quite a lot of problems (doesn't
boot at all on non NUMA and misassigns cores on Opteron systems).

Mark it as experimental and warn against its use for now.

It's still default y for SUMMIT/NUMAQ because it'll presumably
work on these systems.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This causes boot failures for some people.
It looks like in fact that some SILO provided
ramdisk images should not be KERNBASE normalized.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Otherwise the compiler can't see the things like the
per-cpu area base register are changing.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 196705c9.  It was
reported to cause a regression by Daniel Exner, and Arjan van de Ven
points out that we actually already have infrastructure in place for
setting limits on acceptable DMA latency that would be the much more
correct fix for the problem with some Broadcom EHCI controllers.

Fixed up trivial conflicts due to the changes to support big-endian host
controller descriptors in drivers/usb/host/{ehci-sched.c,ehci.h}.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch uses kzalloc to zero all of struct dio rather than manually
trying to track which fields we rely on being zero.  It passed aio+dio
stress testing and some bug regression testing on ext3.

This patch was introduced by Linus in the conversation that lead up to
Badari's minimal fix to manually zero .map_bh.b_state in commit:

  6a648fa7

It makes the code a bit smaller.  Maybe a couple fewer cachelines to
load, if we're lucky:

   text    data     bss     dec     hex filename
3285925  568506 1304616 5159047  4eb887 vmlinux
3285797  568506 1304616 5158919  4eb807 vmlinux.patched

I was unable to measure a stable difference in the number of cpu cycles
spent in blockdev_direct_IO() when pushing aio+dio 256K reads at
~340MB/s.

So the resulting intent of the patch isn't a performance gain but to
avoid exposing ourselves to the risk of finding another field like
.map_bh.b_state where we rely on zeroing but don't enforce it in the
code.
Signed-off-by: NZach Brown <zach.brown@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>