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Drivers: hv: vmbus: Remove the lock field from the vmbus_channel struct

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The spinlock is (now) *not used to protect test-and-set accesses
to attributes of the structure or sc_list operations.

There is, AFAICT, a distinct lack of {WRITE,READ}_ONCE()s in the
handling of channel->state, but the changes below do not seem to
make things "worse".  ;-)

Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200617164642.37393-9-parri.andrea@gmail.com
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Andrea Parri (Microsoft) 2020-06-17 18:46:42 +02:00 committed by Wei Liu
parent 21d2052c7a
commit 775f43facf
3 changed files with 1 additions and 12 deletions
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6
drivers/hv/channel.c
View file

@ -129,12 +129,8 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
send_pages = newchannel->ringbuffer_send_offset;
recv_pages = newchannel->ringbuffer_pagecount - send_pages;
spin_lock_irqsave(&newchannel->lock, flags);
if (newchannel->state != CHANNEL_OPEN_STATE) {
spin_unlock_irqrestore(&newchannel->lock, flags);
if (newchannel->state != CHANNEL_OPEN_STATE)
return -EINVAL;
}
spin_unlock_irqrestore(&newchannel->lock, flags);
newchannel->state = CHANNEL_OPENING_STATE;
newchannel->onchannel_callback = onchannelcallback;

1
drivers/hv/channel_mgmt.c
View file

@ -317,7 +317,6 @@ static struct vmbus_channel *alloc_channel(void)
return NULL;
spin_lock_init(&channel->sched_lock);
spin_lock_init(&channel->lock);
init_completion(&channel->rescind_event);
INIT_LIST_HEAD(&channel->sc_list);

6
include/linux/hyperv.h
View file

@ -840,12 +840,6 @@ struct vmbus_channel {
*/
void (*chn_rescind_callback)(struct vmbus_channel *channel);
/*
* The spinlock to protect the structure. It is being used to protect
* test-and-set access to various attributes of the structure as well
* as all sc_list operations.
*/
spinlock_t lock;
/*
* All Sub-channels of a primary channel are linked here.
*/