| Message ID | 20220328144244.100228-2-parri.andrea@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Lorenzo Pieralisi |
| Headers | show |
| Series | PCI: hv: Miscellaneous changes | expand |
From: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Sent: Monday, March 28, 2022 7:43 AM > > vmbus_requestor has included code for handling unsolicited messages > since its introduction with commit e8b7db38449ac ("Drivers: hv: vmbus: > Add vmbus_requestor data structure for VMBus hardening"); such code was > motivated by the early use of vmbus_requestor from storvsc. Since > storvsc moved to a tag-based mechanism to generate/retrieve request IDs > with commit bf5fd8cae3c8f ("scsi: storvsc: Use blk_mq_unique_tag() to > generate requestIDs"), the special handling of unsolicited messages in > vmbus_requestor is not useful and can be removed. > > Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> > --- > drivers/hv/channel.c | 13 +------------ > 1 file changed, 1 insertion(+), 12 deletions(-) > > diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c > index dc5c35210c16a..a253eee3aeb1a 100644 > --- a/drivers/hv/channel.c > +++ b/drivers/hv/channel.c > @@ -1243,11 +1243,7 @@ u64 vmbus_next_request_id(struct vmbus_channel > *channel, u64 rqst_addr) > > spin_unlock_irqrestore(&rqstor->req_lock, flags); > > - /* > - * Cannot return an ID of 0, which is reserved for an unsolicited > - * message from Hyper-V. > - */ > - return current_id + 1; > + return current_id; > } > EXPORT_SYMBOL_GPL(vmbus_next_request_id); > > @@ -1268,15 +1264,8 @@ u64 vmbus_request_addr(struct vmbus_channel *channel, > u64 trans_id) > if (!channel->rqstor_size) > return VMBUS_NO_RQSTOR; > > - /* Hyper-V can send an unsolicited message with ID of 0 */ > - if (!trans_id) > - return trans_id; > - > spin_lock_irqsave(&rqstor->req_lock, flags); > > - /* Data corresponding to trans_id is stored at trans_id - 1 */ > - trans_id--; > - > /* Invalid trans_id */ > if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap)) { > spin_unlock_irqrestore(&rqstor->req_lock, flags); > -- > 2.25.1 Reviewed-by: Michael Kelley <mikelley@microsoft.com>
On Mon, Mar 28, 2022 at 04:42:41PM +0200, Andrea Parri (Microsoft) wrote: > vmbus_requestor has included code for handling unsolicited messages > since its introduction with commit e8b7db38449ac ("Drivers: hv: vmbus: > Add vmbus_requestor data structure for VMBus hardening"); such code was > motivated by the early use of vmbus_requestor from storvsc. Since > storvsc moved to a tag-based mechanism to generate/retrieve request IDs > with commit bf5fd8cae3c8f ("scsi: storvsc: Use blk_mq_unique_tag() to > generate requestIDs"), the special handling of unsolicited messages in > vmbus_requestor is not useful and can be removed. As it turns out, this is not quite right. In particular... > @@ -1243,11 +1243,7 @@ u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr) > > spin_unlock_irqrestore(&rqstor->req_lock, flags); > > - /* > - * Cannot return an ID of 0, which is reserved for an unsolicited > - * message from Hyper-V. > - */ > - return current_id + 1; > + return current_id; Hyper-V treats requests with ID of 0 as "non-transactional" and it does not respond to such requests. > @@ -1268,15 +1264,8 @@ u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) > if (!channel->rqstor_size) > return VMBUS_NO_RQSTOR; > > - /* Hyper-V can send an unsolicited message with ID of 0 */ > - if (!trans_id) > - return trans_id; This remains problematic: I will elaborate and propose some solution in the next iteration (to be sent shortly). Thanks, Andrea > - > spin_lock_irqsave(&rqstor->req_lock, flags); > > - /* Data corresponding to trans_id is stored at trans_id - 1 */ > - trans_id--; > - > /* Invalid trans_id */ > if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap)) { > spin_unlock_irqrestore(&rqstor->req_lock, flags);
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index dc5c35210c16a..a253eee3aeb1a 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -1243,11 +1243,7 @@ u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr) spin_unlock_irqrestore(&rqstor->req_lock, flags); - /* - * Cannot return an ID of 0, which is reserved for an unsolicited - * message from Hyper-V. - */ - return current_id + 1; + return current_id; } EXPORT_SYMBOL_GPL(vmbus_next_request_id); @@ -1268,15 +1264,8 @@ u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) if (!channel->rqstor_size) return VMBUS_NO_RQSTOR; - /* Hyper-V can send an unsolicited message with ID of 0 */ - if (!trans_id) - return trans_id; - spin_lock_irqsave(&rqstor->req_lock, flags); - /* Data corresponding to trans_id is stored at trans_id - 1 */ - trans_id--; - /* Invalid trans_id */ if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap)) { spin_unlock_irqrestore(&rqstor->req_lock, flags);
vmbus_requestor has included code for handling unsolicited messages since its introduction with commit e8b7db38449ac ("Drivers: hv: vmbus: Add vmbus_requestor data structure for VMBus hardening"); such code was motivated by the early use of vmbus_requestor from storvsc. Since storvsc moved to a tag-based mechanism to generate/retrieve request IDs with commit bf5fd8cae3c8f ("scsi: storvsc: Use blk_mq_unique_tag() to generate requestIDs"), the special handling of unsolicited messages in vmbus_requestor is not useful and can be removed. Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> --- drivers/hv/channel.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-)