linux/lib
Linus Torvalds e7d33bb5ea lockref: add ability to mark lockrefs "dead"
The only actual current lockref user (dcache) uses zero reference counts
even for perfectly live dentries, because it's a cache: there may not be
any users, but that doesn't mean that we want to throw away the dentry.

At the same time, the dentry cache does have a notion of a truly "dead"
dentry that we must not even increment the reference count of, because
we have pruned it and it is not valid.

Currently that distinction is not visible in the lockref itself, and the
dentry cache validation uses "lockref_get_or_lock()" to either get a new
reference to a dentry that already had existing references (and thus
cannot be dead), or get the dentry lock so that we can then verify the
dentry and increment the reference count under the lock if that
verification was successful.

That's all somewhat complicated.

This adds the concept of being "dead" to the lockref itself, by simply
using a count that is negative.  This allows a usage scenario where we
can increment the refcount of a dentry without having to validate it,
and pushing the special "we killed it" case into the lockref code.

The dentry code itself doesn't actually use this yet, and it's probably
too late in the merge window to do that code (the dentry_kill() code
with its "should I decrement the count" logic really is pretty complex
code), but let's introduce the concept at the lockref level now.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-07 15:49:18 -07:00
..
fonts lib: Move fonts from drivers/video/console/ to lib/fonts/ 2013-06-28 10:28:22 +02:00
lz4 lib/lz4: correct the LZ4 license 2013-08-23 09:51:22 -07:00
lzo lib/lzo: Update LZO compression to current upstream version 2013-02-20 19:36:01 +01:00
mpi alpha: Modernize lib/mpi/longlong.h 2013-07-19 13:54:23 -07:00
raid6 lib/raid6: add ARM-NEON accelerated syndrome calculation 2013-07-08 22:09:18 +01:00
reed_solomon
xz decompressors: fix typo "POWERPC" 2013-03-13 15:21:48 -07:00
zlib_deflate
zlib_inflate
.gitignore
argv_split.c argv_split(): teach it to handle mutable strings 2013-04-29 18:28:19 -07:00
asn1_decoder.c
atomic64_test.c
atomic64.c
audit.c
average.c
bcd.c
bch.c
bitmap.c
bitrev.c
bsearch.c
btree.c
bug.c taint: add explicit flag to show whether lock dep is still OK. 2013-01-21 17:17:57 +10:30
build_OID_registry X.509: do not emit any informational output 2013-06-19 17:54:06 +02:00
bust_spinlocks.c printk: Provide a wake_up_klogd() off-case 2013-03-22 16:41:20 -07:00
check_signature.c
checksum.c asm-generic headers: Allow yet more arch overrides in checksum.h 2013-02-11 20:00:33 +05:30
clz_ctz.c lib: add weak clz/ctz functions 2013-07-09 10:33:30 -07:00
clz_tab.c
cmdline.c
cordic.c
cpu_rmap.c
cpu-notifier-error-inject.c
cpumask.c
crc7.c
crc8.c
crc16.c
crc32.c
crc32defs.h
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c Reinstate "crypto: crct10dif - Wrap crc_t10dif function all to use crypto transform framework" 2013-09-07 12:56:26 +10:00
ctype.c
debug_locks.c mutex: Add support for wound/wait style locks 2013-06-26 12:10:56 +02:00
debugobjects.c debugobjects: Make debug_object_activate() return status 2013-08-18 17:39:55 -07:00
dec_and_lock.c
decompress_bunzip2.c
decompress_inflate.c
decompress_unlz4.c lib: add support for LZ4-compressed kernel 2013-07-09 10:33:30 -07:00
decompress_unlzma.c
decompress_unlzo.c lib/lzo: Rename lzo1x_decompress.c to lzo1x_decompress_safe.c 2013-02-20 19:36:00 +01:00
decompress_unxz.c
decompress.c lib: add support for LZ4-compressed kernel 2013-07-09 10:33:30 -07:00
devres.c lib/devres.c: fix misplaced #endif 2013-02-27 19:10:09 -08:00
digsig.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2013-02-21 08:18:12 -08:00
div64.c Revert "math64: New div64_u64_rem helper" 2013-04-30 19:13:05 +02:00
dma-debug.c dma-debug: update DMA debug API to better handle multiple mappings of a buffer 2013-03-22 16:41:20 -07:00
dump_stack.c x86, asmlinkage: Make dump_stack visible 2013-08-06 14:21:01 -07:00
dynamic_debug.c dynamic debug: line queries failing due to uninitialized local variable 2013-08-28 12:10:53 -07:00
dynamic_queue_limits.c
earlycpio.c earlycpio.c: Fix the confusing comment of find_cpio_data(). 2013-08-14 23:24:01 +02:00
extable.c
fault-inject.c debugfs: add get/set for atomic types 2013-06-03 13:55:01 -07:00
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
fdt.c
find_last_bit.c
find_next_bit.c
flex_array.c
flex_proportions.c
gcd.c
gen_crc32table.c
genalloc.c genalloc: add devres support, allow to find a managed pool by device 2013-04-29 18:28:13 -07:00
halfmd4.c
hexdump.c
hweight.c
idr.c idr: print a stack dump after ida_remove warning 2013-07-03 16:08:04 -07:00
inflate.c
int_sqrt.c lib/int_sqrt.c: optimize square root algorithm 2013-04-29 18:28:19 -07:00
interval_tree_test_main.c
interval_tree.c
iomap_copy.c
iomap.c
iommu-helper.c
ioremap.c
iovec.c Hoist memcpy_fromiovec/memcpy_toiovec into lib/ 2013-05-20 10:24:22 +09:30
irq_regs.c
is_single_threaded.c
jedec_ddr_data.c
kasprintf.c
Kconfig Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2013-09-07 14:31:18 -07:00
Kconfig.debug kobject: delayed kobject release: help find buggy drivers 2013-07-25 15:39:04 -07:00
Kconfig.kgdb treewide: Fix typo in printk 2013-06-18 13:48:45 +02:00
Kconfig.kmemcheck
kfifo.c kfifo: fix kfifo_alloc() and kfifo_init() 2013-02-27 19:10:23 -08:00
klist.c klist: del waiter from klist_remove_waiters before wakeup waitting process 2013-05-21 10:16:39 -07:00
kobject_uevent.c
kobject.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-09-07 14:35:32 -07:00
kstrtox.c
kstrtox.h
lcm.c
libcrc32c.c
list_debug.c
list_sort.c lib/: rename random32() to prandom_u32() 2013-04-29 18:28:42 -07:00
llist.c llist: fix/simplify llist_add() and llist_add_batch() 2013-07-13 13:29:24 +04:00
locking-selftest-hardirq.h
locking-selftest-mutex.h
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h
locking-selftest-rsem.h
locking-selftest-softirq.h
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h
locking-selftest-wsem.h
locking-selftest.c mutex: Move ww_mutex definitions to ww_mutex.h 2013-07-12 12:07:46 +02:00
lockref.c lockref: add ability to mark lockrefs "dead" 2013-09-07 15:49:18 -07:00
lru_cache.c lru_cache: introduce lc_get_cumulative() 2013-03-22 22:17:36 -06:00
Makefile lockref: uninline lockref helper functions 2013-09-02 11:58:20 -07:00
md5.c
memory-notifier-error-inject.c
memweight.c
net_utils.c net: core: move mac_pton() to lib/net_utils.c 2013-06-05 12:00:27 -07:00
nlattr.c
notifier-error-inject.c mode_t, whack-a-mole at 11... 2013-04-09 14:13:05 -04:00
notifier-error-inject.h
of-reconfig-notifier-error-inject.c
oid_registry.c Give the OID registry file module info to avoid kernel tainting 2013-05-05 14:38:00 -07:00
parser.c lib/parser.c: fix up comments for valid return values from match_number 2013-02-21 17:22:25 -08:00
pci_iomap.c
percpu_counter.c kernel: delete __cpuinit usage from all core kernel files 2013-07-14 19:36:59 -04:00
percpu-refcount.c percpu-refcount: use RCU-sched insted of normal RCU 2013-06-16 16:12:26 -07:00
percpu-rwsem.c
plist.c
pm-notifier-error-inject.c
prio_heap.c
proportions.c
radix-tree.c
random32.c
ratelimit.c
rational.c
rbtree_test.c rbtree_test: add __init/__exit annotations 2013-04-30 17:04:07 -07:00
rbtree.c
reciprocal_div.c
rwsem-spinlock.c rwsem: simplify __rwsem_do_wake 2013-05-07 07:20:16 -07:00
rwsem.c rwsem: check counter to avoid cmpxchg calls 2013-05-07 16:11:51 -07:00
scatterlist.c lib/scatterlist: error handling in __sg_alloc_table() 2013-07-09 10:33:31 -07:00
sha1.c
show_mem.c mm, show_mem: suppress page counts in non-blockable contexts 2013-04-29 15:54:28 -07:00
smp_processor_id.c
sort.c
spinlock_debug.c
stmp_device.c
string_helpers.c lib/string_helpers: introduce generic string_unescape 2013-04-30 17:04:03 -07:00
string.c
strncpy_from_user.c
strnlen_user.c
swiotlb.c swiotlb: replace dma_length with sg_dma_len() macro 2013-08-09 11:28:42 -04:00
syscall.c
test-kstrtox.c
test-string_helpers.c lib/string_helpers: introduce generic string_unescape 2013-04-30 17:04:03 -07:00
textsearch.c
timerqueue.c
ts_bm.c
ts_fsm.c
ts_kmp.c
ucs2_string.c Move utf16 functions to kernel core and rename 2013-04-15 21:23:03 +01:00
usercopy.c Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS 2013-04-30 17:04:09 -07:00
uuid.c uuid: use prandom_bytes() 2013-04-29 18:28:42 -07:00
vsprintf.c add formats for dentry/file pathnames 2013-09-04 00:13:11 -04:00