linux-toradex.git/kernel/relay.c, branch v4.13-rc7

Merge branch 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-05-02T18:38:06+00:00

Pull splice updates from Al Viro:
 "These actually missed the last cycle; the branch itself is from last
  December"

* 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  make nr_pages calculation in default_file_splice_read() a bit less ugly
  splice/tee/vmsplice: validate flags
  splice_pipe_desc: kill ->flags
  remove spd_release_page()

lib/vsprintf.c: remove %Z support

2017-02-28T02:43:47+00:00

Now that %z is standartised in C99 there is no reason to support %Z.
Unlike %L it doesn't even make format strings smaller.

Use BUILD_BUG_ON in a couple ATM drivers.

In case anyone didn't notice lib/vsprintf.o is about half of SLUB which
is in my opinion is quite an achievement.  Hopefully this patch inspires
someone else to trim vsprintf.c more.

Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2
Signed-off-by: Alexey Dobriyan 
Cc: Andy Shevchenko 
Cc: Rasmus Villemoes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf

2017-02-25T01:46:54+00:00

->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to
take a vma and vmf parameter when the vma already resides in vmf.

Remove the vma parameter to simplify things.

[arnd@arndb.de: fix ARM build]
  Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang 
Signed-off-by: Arnd Bergmann 
Reviewed-by: Ross Zwisler 
Cc: Theodore Ts'o 
Cc: Darrick J. Wong 
Cc: Matthew Wilcox 
Cc: Dave Hansen 
Cc: Christoph Hellwig 
Cc: Jan Kara 
Cc: Dan Williams 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

splice_pipe_desc: kill ->flags

2016-12-27T04:53:38+00:00

no users left

Signed-off-by: Al Viro

relay: check array offset before using it

2016-12-15T00:04:08+00:00

Smatch complains that we started using the array offset before we
checked that it was valid.

Fixes: 017c59c042d0 ('relay: Use per CPU constructs for the relay channel buffer pointers')
Link: http://lkml.kernel.org/r/20161013084947.GC16198@mwanda
Signed-off-by: Dan Carpenter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

relay: Use irq_work instead of plain timer for deferred wakeup

2016-10-11T22:06:32+00:00

Relay avoids calling wake_up_interruptible() for doing the wakeup of
readers/consumers, waiting for the generation of new data, from the
context of a process which produced the data.  This is apparently done to
prevent the possibility of a deadlock in case Scheduler itself is is
generating data for the relay, after acquiring rq->lock.

The following patch used a timer (to be scheduled at next jiffy), for
delegating the wakeup to another context.
	commit 7c9cb38302e78d24e37f7d8a2ea7eed4ae5f2fa7
	Author: Tom Zanussi 
	Date:   Wed May 9 02:34:01 2007 -0700

	relay: use plain timer instead of delayed work

	relay doesn't need to use schedule_delayed_work() for waking readers
	when a simple timer will do.

Scheduling a plain timer, at next jiffies boundary, to do the wakeup
causes a significant wakeup latency for the Userspace client, which makes
relay less suitable for the high-frequency low-payload use cases where the
data gets generated at a very high rate, like multiple sub buffers getting
filled within a milli second.  Moreover the timer is re-scheduled on every
newly produced sub buffer so the timer keeps getting pushed out if sub
buffers are filled in a very quick succession (less than a jiffy gap
between filling of 2 sub buffers).  As a result relay runs out of sub
buffers to store the new data.

By using irq_work it is ensured that wakeup of userspace client, blocked
in the poll call, is done at earliest (through self IPI or next timer
tick) enabling it to always consume the data in time.  Also this makes
relay consistent with printk & ring buffers (trace), as they too use
irq_work for deferred wake up of readers.

[arnd@arndb.de: select CONFIG_IRQ_WORK]
 Link: http://lkml.kernel.org/r/20160912154035.3222156-1-arnd@arndb.de
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1472906487-1559-1-git-send-email-akash.goel@intel.com
Signed-off-by: Peter Zijlstra 
Signed-off-by: Akash Goel 
Cc: Tom Zanussi 
Cc: Chris Wilson 
Cc: Tvrtko Ursulin 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-10-07T22:36:58+00:00

Pull VFS splice updates from Al Viro:
 "There's a bunch of branches this cycle, both mine and from other folks
  and I'd rather send pull requests separately.

  This one is the conversion of ->splice_read() to ITER_PIPE iov_iter
  (and introduction of such). Gets rid of a lot of code in fs/splice.c
  and elsewhere; there will be followups, but these are for the next
  cycle...  Some pipe/splice-related cleanups from Miklos in the same
  branch as well"

* 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  pipe: fix comment in pipe_buf_operations
  pipe: add pipe_buf_steal() helper
  pipe: add pipe_buf_confirm() helper
  pipe: add pipe_buf_release() helper
  pipe: add pipe_buf_get() helper
  relay: simplify relay_file_read()
  switch default_file_splice_read() to use of pipe-backed iov_iter
  switch generic_file_splice_read() to use of ->read_iter()
  new iov_iter flavour: pipe-backed
  fuse_dev_splice_read(): switch to add_to_pipe()
  skb_splice_bits(): get rid of callback
  new helper: add_to_pipe()
  splice: lift pipe_lock out of splice_to_pipe()
  splice: switch get_iovec_page_array() to iov_iter
  splice_to_pipe(): don't open-code wakeup_pipe_readers()
  consistent treatment of EFAULT on O_DIRECT read/write

relay: simplify relay_file_read()

2016-10-05T22:23:57+00:00

to hell with actors...

Signed-off-by: Al Viro

relayfs: Convert to hotplug state machine

2016-09-06T16:30:20+00:00

Install the callbacks via the state machine. They are installed at run time but
relay_prepare_cpu() does not need to be invoked by the boot CPU because
relay_open() was not yet invoked and there are no pools that need to be created.

Signed-off-by: Richard Weinberger 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Sebastian Andrzej Siewior 
Reviewed-by: Sebastian Andrzej Siewior 
Cc: Peter Zijlstra 
Cc: rt@linutronix.de
Cc: Andrew Morton 
Link: http://lkml.kernel.org/r/20160818125731.27256-3-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner

relay: Use per CPU constructs for the relay channel buffer pointers

2016-09-06T16:30:19+00:00

relay essentially needs to maintain a per CPU array of channel buffer
pointers but it manually creates that array.  Instead its better to use
the per CPU constructs, provided by the kernel, to allocate & access the
array of pointer to channel buffers.

Signed-off-by: Akash Goel 
Reviewed-by: Chris Wilson 
Link: http://lkml.kernel.org/r/1470909140-25919-1-git-send-email-akash.goel@intel.com
Signed-off-by: Andrew Morton 
Signed-off-by: Thomas Gleixner