cancel_dirty_page() had some issues and b9ea2515 ("page_writeback:
clean up mess around cancel_dirty_page()") replaced it with
account_page_cleaned() which makes the caller responsible for clearing
the dirty bit; unfortunately, the planned changes for cgroup writeback
support requires synchronization between dirty bit manipulation and
stat updates.  While we can open-code such synchronization in each
account_page_cleaned() callsite, that's gonna be unnecessarily awkward
and verbose.

This patch revives cancel_dirty_page() but in a more restricted form.
All it does is TestClearPageDirty() followed by account_page_cleaned()
invocation if the page was dirty.  This helper covers all
account_page_cleaned() usages except for __delete_from_page_cache()
which is a special case anyway and left alone.  As this leaves no
module user for account_page_cleaned(), EXPORT_SYMBOL() is dropped
from it.

This patch just revives cancel_dirty_page() as a trivial wrapper to
replace equivalent usages and doesn't introduce any functional
changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NJens Axboe <axboe@fb.com>

Storage controllers may expose multiple block devices that share hardware
resources managed by blk-mq. This patch enhances the shared tags so a
low-level driver can access the shared resources not tied to the unshared
h/w contexts. This way the LLD can dynamically add and delete disks and
request queues without having to track all the request_queue hctx's to
iterate outstanding tags.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

We don't need to honor chunk sizes for IO that doesn't carry any
data.
Signed-off-by: NJens Axboe <axboe@fb.com>

Currently dm-multipath has to clone the bios for every request sent
to the lower devices, which wastes cpu cycles and ties down memory.

This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio
to not complete bios attached to a request, which we set on clone
requests similar to bios in a flush sequence.  With this change I/O
errors on a path failure only get propagated to dm-multipath, which
can then either resubmit the I/O or complete the bios on the original
request.

I've done some basic testing of this on a Linux target with ALUA support,
and it survives path failures during I/O nicely.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for
non-chains") regressed all existing callers that followed this pattern:
 1) saving a bio's original bi_end_io
 2) wiring up an intermediate bi_end_io
 3) restoring the original bi_end_io from intermediate bi_end_io
 4) calling bio_endio() to execute the restored original bi_end_io

The regression was due to BIO_CHAIN only ever getting set if
bio_inc_remaining() is called.  For the above pattern it isn't set until
step 3 above (step 2 would've needed to establish BIO_CHAIN).  As such
the first bio_endio(), in step 2 above, never decremented __bi_remaining
before calling the intermediate bi_end_io -- leaving __bi_remaining with
the value 1 instead of 0.  When bio_inc_remaining() occurred during step
3 it brought it to a value of 2.  When the second bio_endio() was
called, in step 4 above, it should've called the original bi_end_io but
it didn't because there was an extra reference that wasn't dropped (due
to atomic operations being optimized away since BIO_CHAIN wasn't set
upfront).

Fix this issue by removing the __bi_remaining management complexity for
all callers that use the above pattern -- bio_chain() is the only
interface that _needs_ to be concerned with __bi_remaining.  For the
above pattern callers just expect the bi_end_io they set to get called!
Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls
that aren't associated with the bio_chain() interface.

Also, the bio_inc_remaining() interface has been moved local to bio.c.

Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains")
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This patch exports blkdev_reread_part() for block drivers, also
introduce __blkdev_reread_part().

For some drivers, such as loop, reread of partitions can be run
from the release path, and bd_mutex may already be held prior to
calling ioctl_by_bdev(bdev, BLKRRPART, 0), so introduce
__blkdev_reread_part for use in such cases.

CC: Christoph Hellwig <hch@lst.de>
CC: Jens Axboe <axboe@kernel.dk>
CC: Tejun Heo <tj@kernel.org>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
CC: Markus Pargmann <mpa@pengutronix.de>
CC: Stefan Weinhuber <wein@de.ibm.com>
CC: Stefan Haberland <stefan.haberland@de.ibm.com>
CC: Sebastian Ott <sebott@linux.vnet.ibm.com>
CC: Fabian Frederick <fabf@skynet.be>
CC: Ming Lei <ming.lei@canonical.com>
CC: David Herrmann <dh.herrmann@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: nbd-general@lists.sourceforge.net
CC: linux-s390@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJarod Wilson <jarod@redhat.com>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Stop abusing struct page functionality and the swap end_io handler, and
instead add a modified version of the blk-lib.c bio_batch helpers.

Also move the block I/O code into swap.c as they are directly tied into
each other.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NPavel Machek <pavel@ucw.cz>
Tested-by: NMing Lin <mlin@kernel.org>
Acked-by: NPavel Machek <pavel@ucw.cz>
Acked-by: NRafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: NJens Axboe <axboe@fb.com>

Various previous patches removed bits and left holes, collapse them
all. Leave the reset start bit where it is, we don't need to change
that.
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>

Since the big barrier rewrite/removal in 2007 we never fail FLUSH or
FUA requests, which means we can remove the magic BIO_EOPNOTSUPP flag
to help propagating those to the buffer_head layer.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>

lockdep gets unhappy about the not disabling irqs when using the queue_lock
around it.  Instead of trying to fix that up just switch to an atomic_t
and get rid of the lock.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

This removes the request types and hacks from the block code and into the
old IDE driver.  There is a small amunt of code duplication due to this,
but it's not too bad.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

These values are only used by the IDE driver, so move them into it
by allowing drivers to take cmd_type values after the first private
one.  Note that we have to turn cmd_type into a plain unsigned integer
so that gcc doesn't complain about mismatching enum types.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Struct bio has a reference count that controls when it can be freed.
Most uses cases is allocating the bio, which then returns with a
single reference to it, doing IO, and then dropping that single
reference. We can remove this atomic_dec_and_test() in the completion
path, if nobody else is holding a reference to the bio.

If someone does call bio_get() on the bio, then we flag the bio as
now having valid count and that we must properly honor the reference
count when it's being put.
Tested-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Struct bio has an atomic ref count for chained bio's, and we use this
to know when to end IO on the bio. However, most bio's are not chained,
so we don't need to always introduce this atomic operation as part of
ending IO.

Add a helper to elevate the bi_remaining count, and flag the bio as
now actually needing the decrement at end_io time. Rename the field
to __bi_remaining to catch any current users of this doing the
incrementing manually.

For high IOPS workloads, this reduces the overhead of bio_endio()
substantially.
Tested-by: NRobert Elliott <elliott@hp.com>
Acked-by: NKent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

In commit 0b053c95 ("lib: memzero_explicit: use barrier instead
of OPTIMIZER_HIDE_VAR"), we made memzero_explicit() more robust in
case LTO would decide to inline memzero_explicit() and eventually
find out it could be elimiated as dead store.

While using barrier() works well for the case of gcc, recent efforts
from LLVMLinux people suggest to use llvm as an alternative to gcc,
and there, Stephan found in a simple stand-alone user space example
that llvm could nevertheless optimize and thus elimitate the memset().
A similar issue has been observed in the referenced llvm bug report,
which is regarded as not-a-bug.

Based on some experiments, icc is a bit special on its own, while it
doesn't seem to eliminate the memset(), it could do so with an own
implementation, and then result in similar findings as with llvm.

The fix in this patch now works for all three compilers (also tested
with more aggressive optimization levels). Arguably, in the current
kernel tree it's more of a theoretical issue, but imho, it's better
to be pedantic about it.

It's clearly visible with gcc/llvm though, with the below code: if we
would have used barrier() only here, llvm would have omitted clearing,
not so with barrier_data() variant:

  static inline void memzero_explicit(void *s, size_t count)
  {
    memset(s, 0, count);
    barrier_data(s);
  }

  int main(void)
  {
    char buff[20];
    memzero_explicit(buff, sizeof(buff));
    return 0;
  }

  $ gcc -O2 test.c
  $ gdb a.out
  (gdb) disassemble main
  Dump of assembler code for function main:
   0x0000000000400400  <+0>: lea   -0x28(%rsp),%rax
   0x0000000000400405  <+5>: movq  $0x0,-0x28(%rsp)
   0x000000000040040e <+14>: movq  $0x0,-0x20(%rsp)
   0x0000000000400417 <+23>: movl  $0x0,-0x18(%rsp)
   0x000000000040041f <+31>: xor   %eax,%eax
   0x0000000000400421 <+33>: retq
  End of assembler dump.

  $ clang -O2 test.c
  $ gdb a.out
  (gdb) disassemble main
  Dump of assembler code for function main:
   0x00000000004004f0  <+0>: xorps  %xmm0,%xmm0
   0x00000000004004f3  <+3>: movaps %xmm0,-0x18(%rsp)
   0x00000000004004f8  <+8>: movl   $0x0,-0x8(%rsp)
   0x0000000000400500 <+16>: lea    -0x18(%rsp),%rax
   0x0000000000400505 <+21>: xor    %eax,%eax
   0x0000000000400507 <+23>: retq
  End of assembler dump.

As gcc, clang, but also icc defines __GNUC__, it's sufficient to define
this in compiler-gcc.h only to be picked up. For a fallback or otherwise
unsupported compiler, we define it as a barrier. Similarly, for ecc which
does not support gcc inline asm.

Reference: https://llvm.org/bugs/show_bug.cgi?id=15495Reported-by: NStephan Mueller <smueller@chronox.de>
Tested-by: NStephan Mueller <smueller@chronox.de>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Stephan Mueller <smueller@chronox.de>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: mancha security <mancha1@zoho.com>
Cc: Mark Charlebois <charlebm@gmail.com>
Cc: Behan Webster <behanw@converseincode.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Here the "other side" refers to the guest or host.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

NLM_F_MULTI must be used only when a NLMSG_DONE message is sent. In fact,
it is sent only at the end of a dump.

Libraries like libnl will wait forever for NLMSG_DONE.

Fixes: e5a55a89 ("net: create generic bridge ops")
Fixes: 815cccbf ("ixgbe: add setlink, getlink support to ixgbe and ixgbevf")
CC: John Fastabend <john.r.fastabend@intel.com>
CC: Sathya Perla <sathya.perla@emulex.com>
CC: Subbu Seetharaman <subbu.seetharaman@emulex.com>
CC: Ajit Khaparde <ajit.khaparde@emulex.com>
CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
CC: intel-wired-lan@lists.osuosl.org
CC: Jiri Pirko <jiri@resnulli.us>
CC: Scott Feldman <sfeldma@gmail.com>
CC: Stephen Hemminger <stephen@networkplumber.org>
CC: bridge@lists.linux-foundation.org
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Looks like audigy emu10k2 (probably emu10k1 - sb live too) support two
modes for DMA. Second mode is useful for 64 bit os with more then 2 GB
of ram (fixes problems with big soundfont loading)

1) 32MB from 2 GB address space using 8192 pages (used now as default)
2) 16MB from 4 GB address space using 4096 pages

Mode is set using HCFG_EXPANDED_MEM flag in HCFG register.
Also format of emu10k2 page table is then different.
Signed-off-by: NPeter Zubaj <pzubaj@marticonet.sk>
Tested-by: NTakashi Iwai <tiwai@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

During commit e252652f ("ACPICA: acpidump: Remove integer types
translation protection.") two 'unsigned char' types got converted to 'u8'.

The result does not compile with gcc-4.5, it can not cope with duplicate
typedefs.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

rajeev-dlh.kumar@st.com email-id doesn't exist anymore as I have left the
company.  Replace ST's id with Rajeev Kumar <rajeevkumar.linux@gmail.com>
Signed-off-by: NRajeev Kumar <rajeevkumar.linux@gmail.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

This is needed by Bluetooth hci_uart module to be able to change speed
of Bluetooth controller and local UART.
Signed-off-by: NFrederic Danis <frederic.danis@linux.intel.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The usb-storage driver sets max_sectors = 240 in its scsi-host template,
for uas we do not want to do that for all devices, but testing has shown
that some devices need it.

This commit adds a US_FL_MAX_SECTORS_240 flag for such devices, and
implements support for it in uas.c, while at it it also adds support
for US_FL_MAX_SECTORS_64 to uas.c.

Cc: stable@vger.kernel.org # 3.16
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This works around a issue with qnap iscsi targets not handling large IOs
very well.

The target returns:

VPD INQUIRY: Block limits page (SBC)
  Maximum compare and write length: 1 blocks
  Optimal transfer length granularity: 1 blocks
  Maximum transfer length: 4294967295 blocks
  Optimal transfer length: 4294967295 blocks
  Maximum prefetch, xdread, xdwrite transfer length: 0 blocks
  Maximum unmap LBA count: 8388607
  Maximum unmap block descriptor count: 1
  Optimal unmap granularity: 16383
  Unmap granularity alignment valid: 0
  Unmap granularity alignment: 0
  Maximum write same length: 0xffffffff blocks
  Maximum atomic transfer length: 0
  Atomic alignment: 0
  Atomic transfer length granularity: 0

and it is *sometimes* able to handle at least one IO of size up to 8 MB. We
have seen in traces where it will sometimes work, but other times it
looks like it fails and it looks like it returns failures if we send
multiple large IOs sometimes. Also it looks like it can return 2 different
errors. It will sometimes send iscsi reject errors indicating out of
resources or it will send invalid cdb illegal requests check conditions.
And then when it sends iscsi rejects it does not seem to handle retries
when there are command sequence holes, so I could not just add code to
try and gracefully handle that error code.

The problem is that we do not have a good contact for the company,
so we are not able to determine under what conditions it returns
which error and why it sometimes works.

So, this patch just adds a new black list flag to set targets like this to
the old max safe sectors of 1024. The max_hw_sectors changes added in 3.19
caused this regression, so I also ccing stable.
Reported-by: NChristian Hesse <list@eworm.de>
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Cc: stable@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

This reverts commits 0a4e6be9
and 80f7fdb1.

The task migration notifier was originally introduced in order to support
the pvclock vsyscall with non-synchronized TSC, but KVM only supports it
with synchronized TSC.  Hence, on KVM the race condition is only needed
due to a bad implementation on the host side, and even then it's so rare
that it's mostly theoretical.

As far as KVM is concerned it's possible to fix the host, avoiding the
additional complexity in the vDSO and the (re)introduction of the task
migration notifier.

Xen, on the other hand, hasn't yet implemented vsyscall support at
all, so we do not care about its plans for non-synchronized TSC.
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Suggested-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The bonding modules currently defines four macros with
general names that pollute the global namespace:
DRV_VERSION
DRV_RELDATE
DRV_NAME
DRV_DESCRIPTION

Fixing that by defining a private bonding_priv.h
header files which includes those defines.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When I added pfmemalloc support in build_skb(), I forgot netlink
was using build_skb() with a vmalloc() area.

In this patch I introduce __build_skb() for netlink use,
and build_skb() is a wrapper handling both skb->head_frag and
skb->pfmemalloc

This means netlink no longer has to hack skb->head_frag

[ 1567.700067] kernel BUG at arch/x86/mm/physaddr.c:26!
[ 1567.700067] invalid opcode: 0000 [#1] PREEMPT SMP KASAN
[ 1567.700067] Dumping ftrace buffer:
[ 1567.700067]    (ftrace buffer empty)
[ 1567.700067] Modules linked in:
[ 1567.700067] CPU: 9 PID: 16186 Comm: trinity-c182 Not tainted 4.0.0-next-20150424-sasha-00037-g4796e21 #2167
[ 1567.700067] task: ffff880127efb000 ti: ffff880246770000 task.ti: ffff880246770000
[ 1567.700067] RIP: __phys_addr (arch/x86/mm/physaddr.c:26 (discriminator 3))
[ 1567.700067] RSP: 0018:ffff8802467779d8  EFLAGS: 00010202
[ 1567.700067] RAX: 000041000ed8e000 RBX: ffffc9008ed8e000 RCX: 000000000000002c
[ 1567.700067] RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffffffb3fd6049
[ 1567.700067] RBP: ffff8802467779f8 R08: 0000000000000019 R09: ffff8801d0168000
[ 1567.700067] R10: ffff8801d01680c7 R11: ffffed003a02d019 R12: ffffc9000ed8e000
[ 1567.700067] R13: 0000000000000f40 R14: 0000000000001180 R15: ffffc9000ed8e000
[ 1567.700067] FS:  00007f2a7da3f700(0000) GS:ffff8801d1000000(0000) knlGS:0000000000000000
[ 1567.700067] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1567.700067] CR2: 0000000000738308 CR3: 000000022e329000 CR4: 00000000000007e0
[ 1567.700067] Stack:
[ 1567.700067]  ffffc9000ed8e000 ffff8801d0168000 ffffc9000ed8e000 ffff8801d0168000
[ 1567.700067]  ffff880246777a28 ffffffffad7c0a21 0000000000001080 ffff880246777c08
[ 1567.700067]  ffff88060d302e68 ffff880246777b58 ffff880246777b88 ffffffffad9a6821
[ 1567.700067] Call Trace:
[ 1567.700067] build_skb (include/linux/mm.h:508 net/core/skbuff.c:316)
[ 1567.700067] netlink_sendmsg (net/netlink/af_netlink.c:1633 net/netlink/af_netlink.c:2329)
[ 1567.774369] ? sched_clock_cpu (kernel/sched/clock.c:311)
[ 1567.774369] ? netlink_unicast (net/netlink/af_netlink.c:2273)
[ 1567.774369] ? netlink_unicast (net/netlink/af_netlink.c:2273)
[ 1567.774369] sock_sendmsg (net/socket.c:614 net/socket.c:623)
[ 1567.774369] sock_write_iter (net/socket.c:823)
[ 1567.774369] ? sock_sendmsg (net/socket.c:806)
[ 1567.774369] __vfs_write (fs/read_write.c:479 fs/read_write.c:491)
[ 1567.774369] ? get_lock_stats (kernel/locking/lockdep.c:249)
[ 1567.774369] ? default_llseek (fs/read_write.c:487)
[ 1567.774369] ? vtime_account_user (kernel/sched/cputime.c:701)
[ 1567.774369] ? rw_verify_area (fs/read_write.c:406 (discriminator 4))
[ 1567.774369] vfs_write (fs/read_write.c:539)
[ 1567.774369] SyS_write (fs/read_write.c:586 fs/read_write.c:577)
[ 1567.774369] ? SyS_read (fs/read_write.c:577)
[ 1567.774369] ? __this_cpu_preempt_check (lib/smp_processor_id.c:63)
[ 1567.774369] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2594 kernel/locking/lockdep.c:2636)
[ 1567.774369] ? trace_hardirqs_on_thunk (arch/x86/lib/thunk_64.S:42)
[ 1567.774369] system_call_fastpath (arch/x86/kernel/entry_64.S:261)

Fixes: 79930f58 ("net: do not deplete pfmemalloc reserve")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I_DIO_WAKEUP is never directly used, but fix it up anyway.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

do_blockdev_direct_IO() increments and decrements the inode
->i_dio_count for each IO operation. It does this to protect against
truncate of a file. Block devices don't need this sort of protection.

For a capable multiqueue setup, this atomic int is the only shared
state between applications accessing the device for O_DIRECT, and it
presents a scaling wall for that. In my testing, as much as 30% of
system time is spent incrementing and decrementing this value. A mixed
read/write workload improved from ~2.5M IOPS to ~9.6M IOPS, with
better latencies too. Before:

clat percentiles (usec):
 |  1.00th=[   33],  5.00th=[   34], 10.00th=[   34], 20.00th=[   34],
 | 30.00th=[   34], 40.00th=[   34], 50.00th=[   35], 60.00th=[   35],
 | 70.00th=[   35], 80.00th=[   35], 90.00th=[   37], 95.00th=[   80],
 | 99.00th=[   98], 99.50th=[  151], 99.90th=[  155], 99.95th=[  155],
 | 99.99th=[  165]

After:

clat percentiles (usec):
 |  1.00th=[   95],  5.00th=[  108], 10.00th=[  129], 20.00th=[  149],
 | 30.00th=[  155], 40.00th=[  161], 50.00th=[  167], 60.00th=[  171],
 | 70.00th=[  177], 80.00th=[  185], 90.00th=[  201], 95.00th=[  270],
 | 99.00th=[  390], 99.50th=[  398], 99.90th=[  418], 99.95th=[  422],
 | 99.99th=[  438]

In other setups, Robert Elliott reported seeing good performance
improvements:

https://lkml.org/lkml/2015/4/3/557

The more applications accessing the device, the worse it gets.

Add a new direct-io flags, DIO_SKIP_DIO_COUNT, which tells
do_blockdev_direct_IO() that it need not worry about incrementing
or decrementing the inode i_dio_count for this caller.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Elliott, Robert (Server Storage) <elliott@hp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJens Axboe <axboe@fb.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Might not have an outdev yet. We'll oops when iface goes down while skbs
are still nfqueue'd:

RIP: 0010:[<ffffffff81422a2f>]  [<ffffffff81422a2f>] dev_cmp+0x4f/0x80
nfqnl_rcv_dev_event+0xe2/0x150
notifier_call_chain+0x53/0xa0

Fixes: c737b7c4 ("netfilter: bridge: add helpers for fetching physin/outdev")
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

[ 3897.923145] BUG: unable to handle kernel NULL pointer dereference at
 0000000000000080
[ 3897.931025] IP: [<ffffffffa9f27686>] reqsk_timer_handler+0x1a6/0x243

There is a race when reqsk_timer_handler() and tcp_check_req() call
inet_csk_reqsk_queue_unlink() on the same req at the same time.

Before commit fa76ce73 ("inet: get rid of central tcp/dccp listener
timer"), listener spinlock was held and race could not happen.

To solve this bug, we change reqsk_queue_unlink() to not assume req
must be found, and we return a status, to conditionally release a
refcount on the request sock.

This also means tcp_check_req() in non fastopen case might or not
consume req refcount, so tcp_v6_hnd_req() & tcp_v4_hnd_req() have
to properly handle this.

(Same remark for dccp_check_req() and its callers)

inet_csk_reqsk_queue_drop() is now too big to be inlined, as it is
called 4 times in tcp and 3 times in dccp.

Fixes: fa76ce73 ("inet: get rid of central tcp/dccp listener timer")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The conversion of mac80211's station table to rhashtable had a bug
that I found by accident in code review, that hadn't been found as
rhashtable apparently managed to have a maximum hash chain length
of one (!) in all our testing.

In order to test the bug and verify the fix I set my rhashtable's
max_size very low (4) in order to force getting hash collisions.

At that point, rhashtable WARNed in rhashtable_insert_rehash() but
didn't actually reject the hash table insertion. This caused it to
lose insertions - my master list of stations would have 9 entries,
but the rhashtable only had 5. This may warrant a deeper look, but
that WARN_ON() just shouldn't happen.

Fix this by not returning true from rht_grow_above_100() when the
rhashtable's max_size has been reached - in this case the user is
explicitly configuring it to be at most that big, so even if it's
now above 100% it shouldn't attempt to resize.

This fixes the "lost insertion" issue and consequently allows my
code to display its error (and verify my fix for it.)
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Acked-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This file is only used internally to the NFS v4 module, so it doesn't
need to be in the global include path.  I also renamed it from
nfs_idmap.h to nfs4idmap.h to emphasize that it's an NFSv4-only include
file.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The idmapper is completely internal to the NFS v4 module, so this macro
will always evaluate to true.  This patch also removes unnecessary
includes of this file from the generic NFS client.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

v2: gracefully handle the case where some dentry pointers end up NULL
    and be more dilligent about zeroing out dentry pointers

We currently have a problem that SELinux policy is being enforced when
creating debugfs files. If a debugfs file is created as a side effect of
doing some syscall, then that creation can fail if the SELinux policy
for that process prevents it.

This seems wrong. We don't do that for files under /proc, for instance,
so Bruce has proposed a patch to fix that.

While discussing that patch however, Greg K.H. stated:

    "No kernel code should care / fail if a debugfs function fails, so
     please fix up the sunrpc code first."

This patch converts all of the sunrpc debugfs setup code to be void
return functins, and the callers to not look for errors from those
functions.

This should allow rpc_clnt and rpc_xprt creation to work, even if the
kernel fails to create debugfs files for some reason.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: N"J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This patch adds a GETATTR to the end of ALLOCATE and DEALLOCATE
operations so we can set the updated inode size and change attribute
directly.  DEALLOCATE will still need to release pagecache pages, so
nfs42_proc_deallocate() now calls truncate_pagecache_range() before
contacting the server.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>