linux-toradex.git/include/linux/kref.h, branch v4.19-rc5

kref: remove WARN_ON for NULL release functions

2017-05-09T00:15:14+00:00

The kref functions check for NULL release functions.  This WARN_ON seems
rather pointless.  We will eventually release and then just crash
nicely.  It is also somewhat expensive because these functions are
inlined in a lot of places.  Removing the WARN_ONs saves around 2.3k in
this kernel (likely more in others with more drivers)

     text    data     bss     dec     hex filename
  9083992 5367600 11116544        25568136        1862388 vmlinux-before-load-avg
  9070166 5367600 11116544        25554310        185ed86 vmlinux-load-avg

Link: http://lkml.kernel.org/r/20170315021431.13107-5-andi@firstfloor.org
Signed-off-by: Andi Kleen 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kref: Implement 'struct kref' using refcount_t

2017-02-10T08:04:19+00:00

Use the refcount_t 'atomic' type to implement 'struct kref', this makes kref
more robust by bringing saturation semantics.

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Signed-off-by: Ingo Molnar

locking/atomic, kref: Implement kref_put_lock()

2017-01-18T09:03:29+00:00

Because home-rolling your own is _awesome_, stop doing it. Provide
kref_put_lock(), just like kref_put_mutex() but for a spinlock.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

locking/atomic, kref: Kill kref_sub()

2017-01-14T10:37:19+00:00

By general sentiment kref_sub() is a bad interface, make it go away.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

locking/atomic, kref: Add kref_read()

2017-01-14T10:37:18+00:00

Since we need to change the implementation, stop exposing internals.

Provide kref_read() to read the current reference count; typically
used for debug messages.

Kills two anti-patterns:

	atomic_read(&kref->refcount)
	kref->refcount.counter

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

locking/atomic, kref: Add KREF_INIT()

2017-01-14T10:37:18+00:00

Since we need to change the implementation, stop exposing internals.

Provide KREF_INIT() to allow static initialization of struct kref.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

kref: Remove kref_put_spinlock_irqsave()

2015-11-29T03:33:29+00:00

The last user is gone. Hence remove this function.

Signed-off-by: Bart Van Assche 
Cc: Greg Kroah-Hartman 
Cc: Christoph Hellwig 
Cc: Joern Engel 
Signed-off-by: Nicholas Bellinger

Merge branch 'queue' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending

2013-05-16T14:55:07+00:00

Pull target fixes from Nicholas Bellinger:
 "A handful of fixes + minor changes this time around, along with one
  important >= v3.9 regression fix for IBLOCK backends.  The highlights
  include:

   - Use FD_MAX_SECTORS in FILEIO for block_device as
     well as files (agrover)

   - Fix processing of out-of-order CmdSNs with
     iSBD driver (shlomo)

   - Close long-standing target_put_sess_cmd() vs.
     core_tmr_abort_task() race with the addition of
     kref_put_spinlock_irqsave() (joern + greg-kh)

   - Fix IBLOCK WCE=1 + DPOFUA=1 backend WRITE
     regression in >= v3.9 (nab + bootc)

  Note these four patches are CC'ed to stable.

  Also, there is still some work left to be done on the active I/O
  shutdown path in target_wait_for_sess_cmds() used by tcm_qla2xxx +
  ib_isert fabrics that is still being discussed on the list, and will
  hopefully be resolved soon."

* 'queue' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: close target_put_sess_cmd() vs. core_tmr_abort_task() race
  target: removed unused transport_state flag
  target/iblock: Fix WCE=1 + DPOFUA=1 backend WRITE regression
  MAINTAINERS: Update target git tree URL
  iscsi-target: Fix typos in RDMAEXTENSIONS macro usage
  target/rd: Add ramdisk bit for NULLIO operation
  iscsi-target: Fix processing of OOO commands
  iscsi-target: Make buf param of iscsit_do_crypto_hash_buf() const void *
  iscsi-target: Fix NULL pointer dereference in iscsit_send_reject
  target: Have dev/enable show if TCM device is configured
  target: Use FD_MAX_SECTORS/FD_BLOCKSIZE for blockdevs using fileio
  target: Remove unused struct members in se_dev_entry

target: close target_put_sess_cmd() vs. core_tmr_abort_task() race

2013-05-15T08:47:35+00:00

It is possible for one thread to to take se_sess->sess_cmd_lock in
core_tmr_abort_task() before taking a reference count on
se_cmd->cmd_kref, while another thread in target_put_sess_cmd() drops
se_cmd->cmd_kref before taking se_sess->sess_cmd_lock.

This introduces kref_put_spinlock_irqsave() and uses it in
target_put_sess_cmd() to close the race window.

Signed-off-by: Joern Engel 
Acked-by: Greg Kroah-Hartman 
Cc: 
Signed-off-by: Nicholas Bellinger

kref: minor cleanup

2013-05-07T23:09:00+00:00

 - make warning smp-safe
 - result of atomic _unless_zero functions should be checked by caller
   to avoid use-after-free error
 - trivial whitespace fix.

Link: https://lkml.org/lkml/2013/4/12/391

Tested: compile x86, boot machine and run xfstests
Signed-off-by: Anatol Pomozov 
[ Removed line-break, changed to use WARN_ON_ONCE()  - Linus ]
Signed-off-by: Linus Torvalds