Thomas Hellstrom e3a55052f4 kref: Implement kref_get_unless_zero v3 ... commit 4b20db3de8 upstream. This function is intended to simplify locking around refcounting for objects that can be looked up from a lookup structure, and which are removed from that lookup structure in the object destructor. Operations on such objects require at least a read lock around lookup + kref_get, and a write lock around kref_put + remove from lookup structure. Furthermore, RCU implementations become extremely tricky. With a lookup followed by a kref_get_unless_zero *with return value check* locking in the kref_put path can be deferred to the actual removal from the lookup structure and RCU lookups become trivial. v2: Formatting fixes. v3: Invert the return value. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2013-04-16 21:27:26 -07:00
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acpi	Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux	2012-05-05 10:06:06 -07:00
asm-generic	signal: Define __ARCH_HAS_SA_RESTORER so we know whether to clear sa_restorer	2013-04-05 10:04:14 -07:00
crypto	crypto: user - Fix lookup of algorithms with IV generator	2012-03-29 19:52:47 +08:00
drm	drm/radeon: add Richland pci ids	2013-03-28 12:12:13 -07:00
keys
linux	kref: Implement kref_get_unless_zero v3	2013-04-16 21:27:26 -07:00
math-emu
media	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2012-05-14 11:23:37 -07:00
misc
mtd
net	inet: limit length of fragment queue hash table bucket lists	2013-03-28 12:11:54 -07:00
pcmcia
rdma	infiniband: pass rdma_cm module to netlink_dump_start	2012-10-28 10:14:15 -07:00
rxrpc
scsi	SCSI: libsas: fix taskfile corruption in sas_ata_qc_fill_rtf	2012-07-16 09:04:37 -07:00
sound	ALSA: Add a reference counter to card instance	2012-11-17 13:16:13 -08:00
target	target: Add link_magic for fabric allow_link destination target_items	2013-01-21 11:45:24 -08:00
trace	xen/mmu: Use Xen specific TLB flush instead of the generic one.	2012-11-17 13:15:54 -08:00
video	atmel_lcdfb: fix 16-bpp modes on older SOCs	2013-03-20 13:05:00 -07:00
xen	xen/blkback: correctly respond to unknown, non-native requests	2013-04-05 10:04:18 -07:00
Kbuild