Use blk_mq_unique_tag() to generate requestIDs for StorVSC, avoiding
all issues with allocating enough entries in the VMbus requestor.
Suggested-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
---
Changes since RFC:
- pass sentinel values for {init,reset}_request in vmbus_sendpacket()
- remove/inline the storvsc_request_addr() callback
- make storvsc_next_request_id() 'static'
- add code to handle the case of an unsolicited message from Hyper-V
- other minor/style changes
[1] https://lkml.kernel.org/r/20210408161315.341888-1-parri.andrea@xxxxxxxxx
drivers/hv/channel.c | 14 ++---
drivers/hv/ring_buffer.c | 13 +++--
drivers/net/hyperv/netvsc.c | 8 ++-
drivers/net/hyperv/rndis_filter.c | 2 +
drivers/scsi/storvsc_drv.c | 94 +++++++++++++++++++++----------
include/linux/hyperv.h | 13 ++++-
6 files changed, 95 insertions(+), 49 deletions(-)
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index db30be8f9ccea..f78e02ace51e8 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -1121,15 +1121,14 @@ EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
* vmbus_next_request_id - Returns a new request id. It is also
* the index at which the guest memory address is stored.
* Uses a spin lock to avoid race conditions.
- * @rqstor: Pointer to the requestor struct
+ * @channel: Pointer to the VMbus channel struct
* @rqst_add: Guest memory address to be stored in the array
*/
-u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr)
+u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
{
+ struct vmbus_requestor *rqstor = &channel->requestor;
unsigned long flags;
u64 current_id;
- const struct vmbus_channel *channel =
- container_of(rqstor, const struct vmbus_channel, requestor);
/* Check rqstor has been initialized */
if (!channel->rqstor_size)
@@ -1163,16 +1162,15 @@ 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.
- * @rqstor: Pointer to the requestor struct
+ * @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_requestor *rqstor, u64 trans_id)
+u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id)
{
+ struct vmbus_requestor *rqstor = &channel->requestor;
unsigned long flags;
u64 req_addr;
- const struct vmbus_channel *channel =
- container_of(rqstor, const struct vmbus_channel, requestor);
/* Check rqstor has been initialized */
if (!channel->rqstor_size)
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index ecd82ebfd5bc4..2bf57677272b5 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -310,10 +310,12 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
*/
if (desc->flags == VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED) {
- rqst_id = vmbus_next_request_id(&channel->requestor, requestid);
- if (rqst_id == VMBUS_RQST_ERROR) {
- spin_unlock_irqrestore(&outring_info->ring_lock, flags);
- return -EAGAIN;
+ if (channel->next_request_id_callback != NULL) {
+ rqst_id = channel->next_request_id_callback(channel, requestid);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ spin_unlock_irqrestore(&outring_info->ring_lock, flags);
+ return -EAGAIN;
+ }
}
}
desc = hv_get_ring_buffer(outring_info) + old_write;
@@ -341,7 +343,8 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
if (channel->rescind) {
if (rqst_id != VMBUS_NO_RQSTOR) {
/* Reclaim request ID to avoid leak of IDs */
- vmbus_request_addr(&channel->requestor, rqst_id);
+ if (channel->request_addr_callback != NULL)
+ channel->request_addr_callback(channel, rqst_id);
}
return -ENODEV;
}
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index c64cc7639c39c..1a221ce2d6fdc 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -730,7 +730,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
int queue_sends;
u64 cmd_rqst;
- cmd_rqst = vmbus_request_addr(&channel->requestor, (u64)desc->trans_id);
+ cmd_rqst = channel->request_addr_callback(channel, (u64)desc->trans_id);
if (cmd_rqst == VMBUS_RQST_ERROR) {
netdev_err(ndev, "Incorrect transaction id\n");
return;
@@ -790,8 +790,8 @@ static void netvsc_send_completion(struct net_device *ndev,
/* First check if this is a VMBUS completion without data payload */
if (!msglen) {
- cmd_rqst = vmbus_request_addr(&incoming_channel->requestor,
- (u64)desc->trans_id);
+ cmd_rqst = incoming_channel->request_addr_callback(incoming_channel,
+ (u64)desc->trans_id);
if (cmd_rqst == VMBUS_RQST_ERROR) {
netdev_err(ndev, "Invalid transaction id\n");
return;
@@ -1602,6 +1602,8 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
netvsc_poll, NAPI_POLL_WEIGHT);
/* Open the channel */
+ device->channel->next_request_id_callback = vmbus_next_request_id;
+ device->channel->request_addr_callback = vmbus_request_addr;
device->channel->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes);
ret = vmbus_open(device->channel, netvsc_ring_bytes,
netvsc_ring_bytes, NULL, 0,
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 123cc9d25f5ed..ebf34bf3f9075 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1259,6 +1259,8 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
/* Set the channel before opening.*/
nvchan->channel = new_sc;
+ new_sc->next_request_id_callback = vmbus_next_request_id;
+ new_sc->request_addr_callback = vmbus_request_addr;
new_sc->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes);
ret = vmbus_open(new_sc, netvsc_ring_bytes,
netvsc_ring_bytes, NULL, 0,
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 6bc5453cea8a7..b219a266cca80 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -684,6 +684,23 @@ static void storvsc_change_target_cpu(struct vmbus_channel *channel, u32 old,
spin_unlock_irqrestore(&stor_device->lock, flags);
}
+static u64 storvsc_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
+{
+ struct storvsc_cmd_request *request =
+ (struct storvsc_cmd_request *)(unsigned long)rqst_addr;
+
+ if (rqst_addr == VMBUS_RQST_INIT)
+ return VMBUS_RQST_INIT;
+ if (rqst_addr == VMBUS_RQST_RESET)
+ return VMBUS_RQST_RESET;
+
+ /*
+ * Cannot return an ID of 0, which is reserved for an unsolicited
+ * message from Hyper-V.
+ */
+ return (u64)blk_mq_unique_tag(request->cmd->request) + 1;
+}
+
static void handle_sc_creation(struct vmbus_channel *new_sc)
{
struct hv_device *device = new_sc->primary_channel->device_obj;
@@ -698,11 +715,7 @@ static void handle_sc_creation(struct vmbus_channel *new_sc)
memset(&props, 0, sizeof(struct vmstorage_channel_properties));
- /*
- * The size of vmbus_requestor is an upper bound on the number of requests
- * that can be in-progress at any one time across all channels.
- */
- new_sc->rqstor_size = scsi_driver.can_queue;
+ new_sc->next_request_id_callback = storvsc_next_request_id;
ret = vmbus_open(new_sc,
storvsc_ringbuffer_size,
@@ -769,7 +782,7 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns)
ret = vmbus_sendpacket(device->channel, vstor_packet,
(sizeof(struct vstor_packet) -
stor_device->vmscsi_size_delta),
- (unsigned long)request,
+ VMBUS_RQST_INIT,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
@@ -838,7 +851,7 @@ static int storvsc_execute_vstor_op(struct hv_device *device,
ret = vmbus_sendpacket(device->channel, vstor_packet,
(sizeof(struct vstor_packet) -
stor_device->vmscsi_size_delta),
- (unsigned long)request,
+ VMBUS_RQST_INIT,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
if (ret != 0)
@@ -1240,6 +1253,7 @@ static void storvsc_on_channel_callback(void *context)
const struct vmpacket_descriptor *desc;
struct hv_device *device;
struct storvsc_device *stor_device;
+ struct Scsi_Host *shost;
if (channel->primary_channel != NULL)
device = channel->primary_channel->device_obj;
@@ -1250,20 +1264,12 @@ static void storvsc_on_channel_callback(void *context)
if (!stor_device)
return;
- foreach_vmbus_pkt(desc, channel) {
- void *packet = hv_pkt_data(desc);
- struct storvsc_cmd_request *request;
- u64 cmd_rqst;
-
- cmd_rqst = vmbus_request_addr(&channel->requestor,
- desc->trans_id);
- if (cmd_rqst == VMBUS_RQST_ERROR) {
- dev_err(&device->device,
- "Incorrect transaction id\n");
- continue;
- }
+ shost = stor_device->host;
- request = (struct storvsc_cmd_request *)(unsigned long)cmd_rqst;
+ foreach_vmbus_pkt(desc, channel) {
+ struct vstor_packet *packet = hv_pkt_data(desc);
+ struct storvsc_cmd_request *request = NULL;
+ u64 rqst_id = desc->trans_id;
if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) -
stor_device->vmscsi_size_delta) {
@@ -1271,14 +1277,44 @@ static void storvsc_on_channel_callback(void *context)
continue;
}
- if (request == &stor_device->init_request ||
- request == &stor_device->reset_request) {
- memcpy(&request->vstor_packet, packet,
- (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta));
- complete(&request->wait_event);
+ if (rqst_id == VMBUS_RQST_INIT) {
+ request = &stor_device->init_request;
+ } else if (rqst_id == VMBUS_RQST_RESET) {
+ request = &stor_device->reset_request;
} else {
+ /* Hyper-V can send an unsolicited message with ID of 0 */
+ if (rqst_id == 0) {
+ /*
+ * storvsc_on_receive() looks at the vstor_packet in the message
+ * from the ring buffer. If the operation in the vstor_packet is
+ * COMPLETE_IO, then we call storvsc_on_io_completion(), and
+ * dereference the guest memory address. Make sure we don't call
+ * storvsc_on_io_completion() with a guest memory address that is
+ * zero if Hyper-V were to construct and send such a bogus packet.
+ */
+ if (packet->operation == VSTOR_OPERATION_COMPLETE_IO) {
+ dev_err(&device->device, "Invalid packet with ID of 0\n");
+ continue;
+ }
+ } else {
+ struct scsi_cmnd *scmnd;
+
+ /* Transaction 'rqst_id' corresponds to tag 'rqst_id - 1' */
+ scmnd = scsi_host_find_tag(shost, rqst_id - 1);
+ if (scmnd == NULL) {
+ dev_err(&device->device, "Incorrect transaction ID\n");
+ continue;
+ }
+ request = (struct storvsc_cmd_request *)scsi_cmd_priv(scmnd);
+ }
+
storvsc_on_receive(stor_device, packet, request);
+ continue;
}
+
+ memcpy(&request->vstor_packet, packet,
+ (sizeof(struct vstor_packet) - stor_device->vmscsi_size_delta));
+ complete(&request->wait_event);
}
}
@@ -1290,11 +1326,7 @@ static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
memset(&props, 0, sizeof(struct vmstorage_channel_properties));
- /*
- * The size of vmbus_requestor is an upper bound on the number of requests
- * that can be in-progress at any one time across all channels.
- */
- device->channel->rqstor_size = scsi_driver.can_queue;
+ device->channel->next_request_id_callback = storvsc_next_request_id;
ret = vmbus_open(device->channel,
ring_size,
@@ -1620,7 +1652,7 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
ret = vmbus_sendpacket(device->channel, vstor_packet,
(sizeof(struct vstor_packet) -
stor_device->vmscsi_size_delta),
- (unsigned long)&stor_device->reset_request,
+ VMBUS_RQST_RESET,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
if (ret != 0)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 2c18c8e768efe..5692ffa60e022 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -779,7 +779,11 @@ struct vmbus_requestor {
#define VMBUS_NO_RQSTOR U64_MAX
#define VMBUS_RQST_ERROR (U64_MAX - 1)
+/* NetVSC-specific */
#define VMBUS_RQST_ID_NO_RESPONSE (U64_MAX - 2)
+/* StorVSC-specific */
+#define VMBUS_RQST_INIT (U64_MAX - 2)
+#define VMBUS_RQST_RESET (U64_MAX - 3)
struct vmbus_device {
u16 dev_type;
@@ -1007,13 +1011,18 @@ struct vmbus_channel {
u32 fuzz_testing_interrupt_delay;
u32 fuzz_testing_message_delay;
+ /* callback to generate a request ID from a request address */
+ u64 (*next_request_id_callback)(struct vmbus_channel *channel, u64 rqst_addr);
+ /* callback to retrieve a request address from a request ID */
+ u64 (*request_addr_callback)(struct vmbus_channel *channel, u64 rqst_id);
+
/* request/transaction ids for VMBus */
struct vmbus_requestor requestor;
u32 rqstor_size;
};
-u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr);
-u64 vmbus_request_addr(struct vmbus_requestor *rqstor, u64 trans_id);
+u64 vmbus_next_request_id(struct vmbus_channel *channel, 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
