RE: [PATCH 5/6] Drivers: hv: vmbus: Introduce {lock,unlock}_requestor()

Michael Kelley (LINUX)
2022-04-08T15:28:54Z

From: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Sent: Wednesday, April 6, 2022 9:30 PM
>
> To abtract the lock and unlock operations on the requestor spin lock.
> The helpers will come in handy in hv_pci.
>
> No functional change.
>
> Suggested-by: Michael Kelley <mikelley@microsoft.com>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
> ---
> drivers/hv/channel.c | 11 +++++------
> include/linux/hyperv.h | 15 +++++++++++++++
> 2 files changed, 20 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
> index 49f10a603a091..56f7e06c673e4 100644
> --- a/drivers/hv/channel.c
> +++ b/drivers/hv/channel.c
> @@ -1252,12 +1252,12 @@ u64 vmbus_next_request_id(struct vmbus_channel
> *channel, u64 rqst_addr)
> if (!channel->rqstor_size)
> return VMBUS_NO_RQSTOR;
>
> - spin_lock_irqsave(&rqstor->req_lock, flags);
> + lock_requestor(channel, flags);
> current_id = rqstor->next_request_id;
>
> /* Requestor array is full */
> if (current_id >= rqstor->size) {
> - spin_unlock_irqrestore(&rqstor->req_lock, flags);
> + unlock_requestor(channel, flags);
> return VMBUS_RQST_ERROR;
> }
>
> @@ -1267,7 +1267,7 @@ u64 vmbus_next_request_id(struct vmbus_channel
> *channel, u64 rqst_addr)
> /* The already held spin lock provides atomicity */
> bitmap_set(rqstor->req_bitmap, current_id, 1);
>
> - spin_unlock_irqrestore(&rqstor->req_lock, flags);
> + unlock_requestor(channel, flags);
>
> /*
> * Cannot return an ID of 0, which is reserved for an unsolicited
> @@ -1327,13 +1327,12 @@ EXPORT_SYMBOL_GPL(__vmbus_request_addr_match);
> u64 vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
> u64 rqst_addr)
> {
> - struct vmbus_requestor *rqstor = &channel->requestor;
> unsigned long flags;
> u64 req_addr;
>
> - spin_lock_irqsave(&rqstor->req_lock, flags);
> + lock_requestor(channel, flags);
> req_addr = __vmbus_request_addr_match(channel, trans_id, rqst_addr);
> - spin_unlock_irqrestore(&rqstor->req_lock, flags);
> + unlock_requestor(channel, flags);
>
> return req_addr;
> }
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index c77d78f34b96a..015e4ceb43029 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1042,6 +1042,21 @@ struct vmbus_channel {
> u32 max_pkt_size;
> };
>
> +#define lock_requestor(channel, flags) \
> +do { \
> + struct vmbus_requestor *rqstor = &(channel)->requestor; \
> + \
> + spin_lock_irqsave(&rqstor->req_lock, flags); \
> +} while (0)
> +
> +static __always_inline void unlock_requestor(struct vmbus_channel *channel,
> + unsigned long flags)
> +{
> + struct vmbus_requestor *rqstor = &channel->requestor;
> +
> + spin_unlock_irqrestore(&rqstor->req_lock, flags);
> +}
> +
> u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr);
> u64 __vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
> u64 rqst_addr);
> --
> 2.25.1

Reviewed-by: Michael Kelley <mikelley@microsoft.com>