summaryrefslogtreecommitdiffstats
path: root/include/linux/kref.h
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2013-05-16 07:55:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-16 07:55:07 -0700
commit5c64e3a45d43c6e3fa87cbe02e10059171d10812 (patch)
tree4b913307a3f9785aebf6c9271f26ec79ab5db625 /include/linux/kref.h
parentc240a539df4e2d50f86e2f31813ff6b7334cd493 (diff)
parentccf5ae83a6cf3d9cfe9a7038bfe7cd38ab03d5e1 (diff)
downloadlinux-5c64e3a45d43c6e3fa87cbe02e10059171d10812.tar.gz
linux-5c64e3a45d43c6e3fa87cbe02e10059171d10812.tar.bz2
linux-5c64e3a45d43c6e3fa87cbe02e10059171d10812.zip
Merge branch 'queue' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending
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
Diffstat (limited to 'include/linux/kref.h')
-rw-r--r--include/linux/kref.h33
1 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/kref.h b/include/linux/kref.h
index e15828fd71f1..484604d184be 100644
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -19,6 +19,7 @@
#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
+#include <linux/spinlock.h>
struct kref {
atomic_t refcount;
@@ -98,6 +99,38 @@ static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref)
return kref_sub(kref, 1, release);
}
+/**
+ * kref_put_spinlock_irqsave - decrement refcount for object.
+ * @kref: object.
+ * @release: pointer to the function that will clean up the object when the
+ * last reference to the object is released.
+ * This pointer is required, and it is not acceptable to pass kfree
+ * in as this function.
+ * @lock: lock to take in release case
+ *
+ * Behaves identical to kref_put with one exception. If the reference count
+ * drops to zero, the lock will be taken atomically wrt dropping the reference
+ * count. The release function has to call spin_unlock() without _irqrestore.
+ */
+static inline int kref_put_spinlock_irqsave(struct kref *kref,
+ void (*release)(struct kref *kref),
+ spinlock_t *lock)
+{
+ unsigned long flags;
+
+ WARN_ON(release == NULL);
+ if (atomic_add_unless(&kref->refcount, -1, 1))
+ return 0;
+ spin_lock_irqsave(lock, flags);
+ if (atomic_dec_and_test(&kref->refcount)) {
+ release(kref);
+ local_irq_restore(flags);
+ return 1;
+ }
+ spin_unlock_irqrestore(lock, flags);
+ return 0;
+}
+
static inline int kref_put_mutex(struct kref *kref,
void (*release)(struct kref *kref),
struct mutex *lock)