From: Tejun Heo <tj@kernel.org>
To: gregkh@linuxfoundation.org
Cc: linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, stern@rowland.harvard.edu,
JBottomley@parallels.com, bhelgaas@google.com,
Tejun Heo <tj@kernel.org>
Subject: [PATCH 06/12] kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep()
Date: Mon, 3 Feb 2014 14:02:59 -0500 [thread overview]
Message-ID: <1391454185-32143-7-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1391454185-32143-1-git-send-email-tj@kernel.org>
There currently are two mechanisms gating active ref lockdep
annotations - KERNFS_LOCKDEP flag and KERNFS_ACTIVE_REF type mask.
The former disables lockdep annotations in kernfs_get/put_active()
while the latter disables all of kernfs_deactivate().
While KERNFS_ACTIVE_REF also behaves as an optimization to skip the
deactivation step for non-file nodes, the benefit is marginal and it
needlessly diverges code paths. Let's drop KERNFS_ACTIVE_REF.
While at it, add a test helper kernfs_lockdep() to test KERNFS_LOCKDEP
flag so that it's more convenient and the related code can be compiled
out when not enabled.
v2: Refreshed on top of ("kernfs: make kernfs_deactivate() honor
KERNFS_LOCKDEP flag"). As the earlier patch already added
KERNFS_LOCKDEP tests to kernfs_deactivate(), those additions are
dropped from this patch and the existing ones are simply converted
to kernfs_lockdep().
Signed-off-by: Tejun Heo <tj@kernel.org>
---
fs/kernfs/dir.c | 20 +++++++++++++-------
include/linux/kernfs.h | 1 -
2 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 948551d..5cf137b 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -22,6 +22,15 @@ DEFINE_MUTEX(kernfs_mutex);
#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
+static bool kernfs_lockdep(struct kernfs_node *kn)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ return kn->flags & KERNFS_LOCKDEP;
+#else
+ return false;
+#endif
+}
+
/**
* kernfs_name_hash
* @name: Null terminated string to hash
@@ -144,7 +153,7 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
if (!atomic_inc_unless_negative(&kn->active))
return NULL;
- if (kn->flags & KERNFS_LOCKDEP)
+ if (kernfs_lockdep(kn))
rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
return kn;
}
@@ -164,7 +173,7 @@ void kernfs_put_active(struct kernfs_node *kn)
if (unlikely(!kn))
return;
- if (kn->flags & KERNFS_LOCKDEP)
+ if (kernfs_lockdep(kn))
rwsem_release(&kn->dep_map, 1, _RET_IP_);
v = atomic_dec_return(&kn->active);
if (likely(v != KN_DEACTIVATED_BIAS))
@@ -190,16 +199,13 @@ static void kernfs_deactivate(struct kernfs_node *kn)
lockdep_assert_held(&kernfs_mutex);
BUG_ON(!(kn->flags & KERNFS_REMOVED));
- if (!(kernfs_type(kn) & KERNFS_ACTIVE_REF))
- return;
-
/* only the first invocation on @kn should deactivate it */
if (atomic_read(&kn->active) >= 0)
atomic_add(KN_DEACTIVATED_BIAS, &kn->active);
mutex_unlock(&kernfs_mutex);
- if (kn->flags & KERNFS_LOCKDEP) {
+ if (kernfs_lockdep(kn)) {
rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
lock_contended(&kn->dep_map, _RET_IP_);
@@ -209,7 +215,7 @@ static void kernfs_deactivate(struct kernfs_node *kn)
wait_event(root->deactivate_waitq,
atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
- if (kn->flags & KERNFS_LOCKDEP) {
+ if (kernfs_lockdep(kn)) {
lock_acquired(&kn->dep_map, _RET_IP_);
rwsem_release(&kn->dep_map, 1, _RET_IP_);
}
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 38646f6..dc4cd6c 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -35,7 +35,6 @@ enum kernfs_node_type {
};
#define KERNFS_TYPE_MASK 0x000f
-#define KERNFS_ACTIVE_REF KERNFS_FILE
#define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK
enum kernfs_node_flag {
--
1.8.5.3
next prev parent reply other threads:[~2014-02-03 19:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-03 19:02 [PATCHSET v5 driver-core-next] kernfs, sysfs, driver-core: implement synchronous self-removal Tejun Heo
2014-02-03 19:02 ` [PATCH 01/12] kernfs: make kernfs_deactivate() honor KERNFS_LOCKDEP flag Tejun Heo
2014-02-03 19:02 ` [PATCH 02/12] kernfs: replace kernfs_node->u.completion with kernfs_root->deactivate_waitq Tejun Heo
2014-02-03 19:02 ` [PATCH 03/12] kernfs: restructure removal path to fix possible premature return Tejun Heo
2014-02-03 19:02 ` [PATCH 04/12] kernfs: invoke kernfs_unmap_bin_file() directly from kernfs_deactivate() Tejun Heo
2014-02-03 19:02 ` [PATCH 05/12] kernfs: remove kernfs_addrm_cxt Tejun Heo
2014-02-03 19:02 ` Tejun Heo [this message]
2014-02-03 19:03 ` [PATCH 07/12] kernfs: remove KERNFS_REMOVED Tejun Heo
2014-02-03 19:03 ` [PATCH 08/12] kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers Tejun Heo
2014-02-03 19:03 ` [PATCH 09/12] pci: use device_remove_file_self() instead of device_schedule_callback() Tejun Heo
2014-02-03 19:03 ` [PATCH 10/12] scsi: " Tejun Heo
2014-02-03 19:03 ` [PATCH 11/12] s390: " Tejun Heo
2014-02-03 19:03 ` [PATCH 12/12] sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner() Tejun Heo
-- strict thread matches above, loose matches on Subject: below --
2014-01-07 17:59 [PATCHSET driver-core-next] kernfs, sysfs, driver-core: implement synchronous self-removal Tejun Heo
2014-01-07 17:59 ` [PATCH 06/12] kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep() Tejun Heo
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