| Message ID | 20220419122325.10078-5-parri.andrea@gmail.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Delegated to: | Lorenzo Pieralisi |
| Headers | show |
| Series | PCI: hv: VMbus requestor and related fixes | expand |
From: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Sent: Tuesday, April 19, 2022 5:23 AM > > The function can be used to retrieve and clear/remove a transation ID > from a channel requestor, provided the memory address corresponding to > the ID equals a specified address. The function, and its 'lockless' > variant __vmbus_request_addr_match(), will be used by hv_pci. > > Refactor vmbus_request_addr() to reuse the 'newly' introduced code. > > No functional change. > > Suggested-by: Michael Kelley <mikelley@microsoft.com> > Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> > --- > drivers/hv/channel.c | 65 ++++++++++++++++++++++++++++++------------ > include/linux/hyperv.h | 5 ++++ > 2 files changed, 52 insertions(+), 18 deletions(-) > > diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c > index 585a8084848bf..49f10a603a091 100644 > --- a/drivers/hv/channel.c > +++ b/drivers/hv/channel.c > @@ -1279,17 +1279,11 @@ u64 vmbus_next_request_id(struct vmbus_channel > *channel, u64 rqst_addr) > } > EXPORT_SYMBOL_GPL(vmbus_next_request_id); > > -/* > - * vmbus_request_addr - Returns the memory address stored at @trans_id > - * in @rqstor. Uses a spin lock to avoid race conditions. > - * @channel: Pointer to the VMbus channel struct > - * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's > - * next request id. > - */ > -u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) > +/* As in vmbus_request_addr_match() but without the requestor lock */ > +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; > > /* Check rqstor has been initialized */ > @@ -1300,25 +1294,60 @@ u64 vmbus_request_addr(struct vmbus_channel > *channel, u64 trans_id) > if (!trans_id) > return VMBUS_RQST_ERROR; > > - 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); > + if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap)) > return VMBUS_RQST_ERROR; > - } > > req_addr = rqstor->req_arr[trans_id]; > - rqstor->req_arr[trans_id] = rqstor->next_request_id; > - rqstor->next_request_id = trans_id; > + if (rqst_addr == VMBUS_RQST_ADDR_ANY || req_addr == rqst_addr) { > + rqstor->req_arr[trans_id] = rqstor->next_request_id; > + rqstor->next_request_id = trans_id; > > - /* The already held spin lock provides atomicity */ > - bitmap_clear(rqstor->req_bitmap, trans_id, 1); > + /* The already held spin lock provides atomicity */ > + bitmap_clear(rqstor->req_bitmap, trans_id, 1); > + } > + > + return req_addr; > +} > +EXPORT_SYMBOL_GPL(__vmbus_request_addr_match); > + > +/* > + * vmbus_request_addr_match - Clears/removes @trans_id from the @channel's > + * requestor, provided the memory address stored at @trans_id equals @rqst_addr > + * (or provided @rqst_addr matches the sentinel value VMBUS_RQST_ADDR_ANY). > + * > + * Returns the memory address stored at @trans_id, or VMBUS_RQST_ERROR if > + * @trans_id is not contained in the requestor. > + * > + * Acquires and releases the requestor spin lock. > + */ > +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); > + req_addr = __vmbus_request_addr_match(channel, trans_id, rqst_addr); > spin_unlock_irqrestore(&rqstor->req_lock, flags); > + > return req_addr; > } > +EXPORT_SYMBOL_GPL(vmbus_request_addr_match); > + > +/* > + * vmbus_request_addr - Returns the memory address stored at @trans_id > + * in @rqstor. Uses a spin lock to avoid race conditions. > + * @channel: Pointer to the VMbus channel struct > + * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's > + * next request id. > + */ > +u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) > +{ > + return vmbus_request_addr_match(channel, trans_id, > VMBUS_RQST_ADDR_ANY); > +} > EXPORT_SYMBOL_GPL(vmbus_request_addr); > diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h > index a7cb596d893b1..c77d78f34b96a 100644 > --- a/include/linux/hyperv.h > +++ b/include/linux/hyperv.h > @@ -788,6 +788,7 @@ struct vmbus_requestor { > > #define VMBUS_NO_RQSTOR U64_MAX > #define VMBUS_RQST_ERROR (U64_MAX - 1) > +#define VMBUS_RQST_ADDR_ANY U64_MAX > /* NetVSC-specific */ > #define VMBUS_RQST_ID_NO_RESPONSE (U64_MAX - 2) > /* StorVSC-specific */ > @@ -1042,6 +1043,10 @@ struct vmbus_channel { > }; > > 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); > +u64 vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id, > + u64 rqst_addr); > u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id); > > static inline bool is_hvsock_channel(const struct vmbus_channel *c) > -- > 2.25.1 Reviewed-by: Michael Kelley <mikelley@microsoft.com>
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index 585a8084848bf..49f10a603a091 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -1279,17 +1279,11 @@ u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr) } EXPORT_SYMBOL_GPL(vmbus_next_request_id); -/* - * vmbus_request_addr - Returns the memory address stored at @trans_id - * in @rqstor. Uses a spin lock to avoid race conditions. - * @channel: Pointer to the VMbus channel struct - * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's - * next request id. - */ -u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) +/* As in vmbus_request_addr_match() but without the requestor lock */ +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; /* Check rqstor has been initialized */ @@ -1300,25 +1294,60 @@ u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) if (!trans_id) return VMBUS_RQST_ERROR; - 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); + if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap)) return VMBUS_RQST_ERROR; - } req_addr = rqstor->req_arr[trans_id]; - rqstor->req_arr[trans_id] = rqstor->next_request_id; - rqstor->next_request_id = trans_id; + if (rqst_addr == VMBUS_RQST_ADDR_ANY || req_addr == rqst_addr) { + rqstor->req_arr[trans_id] = rqstor->next_request_id; + rqstor->next_request_id = trans_id; - /* The already held spin lock provides atomicity */ - bitmap_clear(rqstor->req_bitmap, trans_id, 1); + /* The already held spin lock provides atomicity */ + bitmap_clear(rqstor->req_bitmap, trans_id, 1); + } + + return req_addr; +} +EXPORT_SYMBOL_GPL(__vmbus_request_addr_match); + +/* + * vmbus_request_addr_match - Clears/removes @trans_id from the @channel's + * requestor, provided the memory address stored at @trans_id equals @rqst_addr + * (or provided @rqst_addr matches the sentinel value VMBUS_RQST_ADDR_ANY). + * + * Returns the memory address stored at @trans_id, or VMBUS_RQST_ERROR if + * @trans_id is not contained in the requestor. + * + * Acquires and releases the requestor spin lock. + */ +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); + req_addr = __vmbus_request_addr_match(channel, trans_id, rqst_addr); spin_unlock_irqrestore(&rqstor->req_lock, flags); + return req_addr; } +EXPORT_SYMBOL_GPL(vmbus_request_addr_match); + +/* + * vmbus_request_addr - Returns the memory address stored at @trans_id + * in @rqstor. Uses a spin lock to avoid race conditions. + * @channel: Pointer to the VMbus channel struct + * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's + * next request id. + */ +u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id) +{ + return vmbus_request_addr_match(channel, trans_id, VMBUS_RQST_ADDR_ANY); +} EXPORT_SYMBOL_GPL(vmbus_request_addr); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index a7cb596d893b1..c77d78f34b96a 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -788,6 +788,7 @@ struct vmbus_requestor { #define VMBUS_NO_RQSTOR U64_MAX #define VMBUS_RQST_ERROR (U64_MAX - 1) +#define VMBUS_RQST_ADDR_ANY U64_MAX /* NetVSC-specific */ #define VMBUS_RQST_ID_NO_RESPONSE (U64_MAX - 2) /* StorVSC-specific */ @@ -1042,6 +1043,10 @@ struct vmbus_channel { }; 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); +u64 vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id, + u64 rqst_addr); u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id); static inline bool is_hvsock_channel(const struct vmbus_channel *c)
The function can be used to retrieve and clear/remove a transation ID from a channel requestor, provided the memory address corresponding to the ID equals a specified address. The function, and its 'lockless' variant __vmbus_request_addr_match(), will be used by hv_pci. Refactor vmbus_request_addr() to reuse the 'newly' introduced code. No functional change. Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> --- drivers/hv/channel.c | 65 ++++++++++++++++++++++++++++++------------ include/linux/hyperv.h | 5 ++++ 2 files changed, 52 insertions(+), 18 deletions(-)