From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
John Kacur <jkacur@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Julia Cartwright <julia@ni.com>,
Daniel Wagner <daniel.wagner@siemens.com>,
tom.zanussi@linux.intel.com
Subject: [PATCH RT 17/24] crypto: cryptd - add a lock instead preempt_disable/local_bh_disable
Date: Fri, 07 Sep 2018 16:59:14 -0400 [thread overview]
Message-ID: <20180907205932.529511011@goodmis.org> (raw)
In-Reply-To: 20180907205857.262840394@goodmis.org
4.14.63-rt41-rc2 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[ Upstream commit 21aedb30d85979697f79a72a084e5d781e323663 ]
cryptd has a per-CPU lock which protected with local_bh_disable() and
preempt_disable().
Add an explicit spin_lock to make the locking context more obvious and
visible to lockdep. Since it is a per-CPU lock, there should be no lock
contention on the actual spinlock.
There is a small race-window where we could be migrated to another CPU
after the cpu_queue has been obtain. This is not a problem because the
actual ressource is protected by the spinlock.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
crypto/cryptd.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index 248f6ba41688..54b7985c8caa 100644
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -37,6 +37,7 @@
struct cryptd_cpu_queue {
struct crypto_queue queue;
struct work_struct work;
+ spinlock_t qlock;
};
struct cryptd_queue {
@@ -115,6 +116,7 @@ static int cryptd_init_queue(struct cryptd_queue *queue,
cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu);
crypto_init_queue(&cpu_queue->queue, max_cpu_qlen);
INIT_WORK(&cpu_queue->work, cryptd_queue_worker);
+ spin_lock_init(&cpu_queue->qlock);
}
return 0;
}
@@ -139,8 +141,10 @@ static int cryptd_enqueue_request(struct cryptd_queue *queue,
atomic_t *refcnt;
bool may_backlog;
- cpu = get_cpu();
- cpu_queue = this_cpu_ptr(queue->cpu_queue);
+ cpu_queue = raw_cpu_ptr(queue->cpu_queue);
+ spin_lock_bh(&cpu_queue->qlock);
+ cpu = smp_processor_id();
+
err = crypto_enqueue_request(&cpu_queue->queue, request);
refcnt = crypto_tfm_ctx(request->tfm);
@@ -157,7 +161,7 @@ static int cryptd_enqueue_request(struct cryptd_queue *queue,
atomic_inc(refcnt);
out_put_cpu:
- put_cpu();
+ spin_unlock_bh(&cpu_queue->qlock);
return err;
}
@@ -173,16 +177,11 @@ static void cryptd_queue_worker(struct work_struct *work)
cpu_queue = container_of(work, struct cryptd_cpu_queue, work);
/*
* Only handle one request at a time to avoid hogging crypto workqueue.
- * preempt_disable/enable is used to prevent being preempted by
- * cryptd_enqueue_request(). local_bh_disable/enable is used to prevent
- * cryptd_enqueue_request() being accessed from software interrupts.
*/
- local_bh_disable();
- preempt_disable();
+ spin_lock_bh(&cpu_queue->qlock);
backlog = crypto_get_backlog(&cpu_queue->queue);
req = crypto_dequeue_request(&cpu_queue->queue);
- preempt_enable();
- local_bh_enable();
+ spin_unlock_bh(&cpu_queue->qlock);
if (!req)
return;
--
2.18.0
next prev parent reply other threads:[~2018-09-07 21:00 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-07 20:58 [PATCH RT 00/24] Linux 4.14.63-rt41-rc2 Steven Rostedt
2018-09-07 20:58 ` [PATCH RT 01/24] sched/fair: Fix CFS bandwidth control lockdep DEADLOCK report Steven Rostedt
2018-09-07 20:58 ` [PATCH RT 02/24] locallock: provide {get,put}_locked_ptr() variants Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 03/24] squashfs: make use of local lock in multi_cpu decompressor Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 04/24] PM / suspend: Prevent might sleep splats (updated) Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 05/24] PM / wakeup: Make events_lock a RAW_SPINLOCK Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 06/24] PM / s2idle: Make s2idle_wait_head swait based Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 07/24] seqlock: provide the same ordering semantics as mainline Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 08/24] Revert "x86: UV: raw_spinlock conversion" Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 09/24] Revert "timer: delay waking softirqs from the jiffy tick" Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 10/24] irqchip/gic-v3-its: Make its_lock a raw_spin_lock_t Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 11/24] sched/migrate_disable: fallback to preempt_disable() instead barrier() Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 12/24] irqchip/gic-v3-its: Move ITS ->pend_page allocation into an early CPU up hook Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 13/24] irqchip/gic-v3-its: Move pending table allocation to init time Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 14/24] x86/ioapic: Dont let setaffinity unmask threaded EOI interrupt too early Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 15/24] efi: Allow efi=runtime Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 16/24] efi: Disable runtime services on RT Steven Rostedt
2018-09-07 20:59 ` Steven Rostedt [this message]
2018-09-07 20:59 ` [PATCH RT 18/24] crypto: scompress - serialize RT percpu scratch buffer access with a local lock Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 19/24] sched/core: Avoid __schedule() being called twice in a row Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 20/24] Revert "arm64/xen: Make XEN depend on !RT" Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 21/24] sched: Allow pinned user tasks to be awakened to the CPU they pinned Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 23/24] Revert "softirq: keep the softirq pending check RT-only" Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 24/24] Linux 4.14.63-rt41-rc2 Steven Rostedt
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