diff options
| -rw-r--r-- | drivers/target/target_core_transport.c | 11 | ||||
| -rw-r--r-- | include/linux/kref.h | 33 |
2 files changed, 38 insertions, 6 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 3243ea790ea..0d4627648b5 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2213,21 +2213,19 @@ static void target_release_cmd_kref(struct kref *kref) { struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref); struct se_session *se_sess = se_cmd->se_sess; - unsigned long flags; - spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); if (list_empty(&se_cmd->se_cmd_list)) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + spin_unlock(&se_sess->sess_cmd_lock); se_cmd->se_tfo->release_cmd(se_cmd); return; } if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + spin_unlock(&se_sess->sess_cmd_lock); complete(&se_cmd->cmd_wait_comp); return; } list_del(&se_cmd->se_cmd_list); - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + spin_unlock(&se_sess->sess_cmd_lock); se_cmd->se_tfo->release_cmd(se_cmd); } @@ -2238,7 +2236,8 @@ static void target_release_cmd_kref(struct kref *kref) */ int target_put_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd) { - return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref); + return kref_put_spinlock_irqsave(&se_cmd->cmd_kref, target_release_cmd_kref, + &se_sess->sess_cmd_lock); } EXPORT_SYMBOL(target_put_sess_cmd); diff --git a/include/linux/kref.h b/include/linux/kref.h index 4972e6e9ca9..7419c02085d 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; @@ -95,6 +96,38 @@ 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) |