[PATCH -mm 3/3] nbd: don't abuse irqsave/irqrestore while taking nbd->tasks_lock

From: Oleg Nesterov
Date: Sun Oct 25 2015 - 10:31:03 EST


Both nbd_thread_recv() and nbd_thread_send() are might_sleep() and
called with irqs enabled(), irqsave/irqrestore make no sense and imo
look confusing.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
drivers/block/nbd.c | 22 ++++++++++------------
1 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 0ffd73c..fd79405 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -406,23 +406,22 @@ static int nbd_thread_recv(struct nbd_device *nbd)
{
struct request *req;
int ret;
- unsigned long flags;

BUG_ON(nbd->magic != NBD_MAGIC);

sk_set_memalloc(nbd->sock->sk);

- spin_lock_irqsave(&nbd->tasks_lock, flags);
+ spin_lock_irq(&nbd->tasks_lock);
nbd->task_recv = current;
- spin_unlock_irqrestore(&nbd->tasks_lock, flags);
+ spin_unlock_irq(&nbd->tasks_lock);

ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
if (ret) {
dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");

- spin_lock_irqsave(&nbd->tasks_lock, flags);
+ spin_lock_irq(&nbd->tasks_lock);
nbd->task_recv = NULL;
- spin_unlock_irqrestore(&nbd->tasks_lock, flags);
+ spin_unlock_irq(&nbd->tasks_lock);

return ret;
}
@@ -439,9 +438,9 @@ static int nbd_thread_recv(struct nbd_device *nbd)

device_remove_file(disk_to_dev(nbd->disk), &pid_attr);

- spin_lock_irqsave(&nbd->tasks_lock, flags);
+ spin_lock_irq(&nbd->tasks_lock);
nbd->task_recv = NULL;
- spin_unlock_irqrestore(&nbd->tasks_lock, flags);
+ spin_unlock_irq(&nbd->tasks_lock);

if (signal_pending(current)) {
dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal",
@@ -543,11 +542,10 @@ static int nbd_thread_send(void *data)
{
struct nbd_device *nbd = data;
struct request *req;
- unsigned long flags;

- spin_lock_irqsave(&nbd->tasks_lock, flags);
+ spin_lock_irq(&nbd->tasks_lock);
nbd->task_send = current;
- spin_unlock_irqrestore(&nbd->tasks_lock, flags);
+ spin_unlock_irq(&nbd->tasks_lock);

set_user_nice(current, MIN_NICE);
while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) {
@@ -581,9 +579,9 @@ static int nbd_thread_send(void *data)
nbd_handle_req(nbd, req);
}

- spin_lock_irqsave(&nbd->tasks_lock, flags);
+ spin_lock_irq(&nbd->tasks_lock);
nbd->task_send = NULL;
- spin_unlock_irqrestore(&nbd->tasks_lock, flags);
+ spin_unlock_irq(&nbd->tasks_lock);

return 0;
}
--
1.5.5.1

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