| /* |
| * Greybus operations |
| * |
| * Copyright 2014 Google Inc. |
| * |
| * Released under the GPLv2 only. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <linux/module.h> |
| #include <linux/workqueue.h> |
| |
| #include "greybus.h" |
| |
| /* |
| * The top bit of the type in an operation message header indicates |
| * whether the message is a request (bit clear) or response (bit set) |
| */ |
| #define GB_OPERATION_TYPE_RESPONSE 0x80 |
| |
| #define OPERATION_TIMEOUT_DEFAULT 1000 /* milliseconds */ |
| |
| /* |
| * XXX This needs to be coordinated with host driver parameters |
| * XXX May need to reduce to allow for message header within a page |
| */ |
| #define GB_OPERATION_MESSAGE_SIZE_MAX 4096 |
| |
| static struct kmem_cache *gb_operation_cache; |
| |
| /* Workqueue to handle Greybus operation completions. */ |
| static struct workqueue_struct *gb_operation_workqueue; |
| |
| /* Protects the cookie representing whether a message is in flight */ |
| static DEFINE_MUTEX(gb_message_mutex); |
| |
| /* |
| * All operation messages (both requests and responses) begin with |
| * a header that encodes the size of the data (header included). |
| * This header also contains a unique identifier, which is used to |
| * keep track of in-flight operations. The header contains an |
| * operation type field, whose interpretation is dependent on what |
| * type of protocol is used over the connection. |
| * |
| * The high bit (0x80) of the operation type field is used to |
| * indicate whether the message is a request (clear) or a response |
| * (set). |
| * |
| * Response messages include an additional status byte, which |
| * communicates the result of the corresponding request. A zero |
| * status value means the operation completed successfully. Any |
| * other value indicates an error; in this case, the payload of the |
| * response message (if any) is ignored. The status byte must be |
| * zero in the header for a request message. |
| * |
| * The wire format for all numeric fields in the header is little |
| * endian. Any operation-specific data begins immediately after the |
| * header, and is 64-bit aligned. |
| */ |
| struct gb_operation_msg_hdr { |
| __le16 size; /* Size in bytes of header + payload */ |
| __le16 operation_id; /* Operation unique id */ |
| __u8 type; /* E.g GB_I2C_TYPE_* or GB_GPIO_TYPE_* */ |
| __u8 result; /* Result of request (in responses only) */ |
| /* 2 bytes pad, must be zero (ignore when read) */ |
| } __aligned(sizeof(u64)); |
| |
| /* XXX Could be per-host device, per-module, or even per-connection */ |
| static DEFINE_SPINLOCK(gb_operations_lock); |
| |
| /* |
| * Set an operation's result. Initially an outgoing operation's |
| * errno value is -EBADR. If no error occurs before sending the |
| * request message the only valid value operation->errno can be |
| * set to is -EINPROGRESS, indicating the request has been (or |
| * rather is about to be) sent. At that point nobody should |
| * be looking at the result until the reponse arrives. |
| * |
| * The first time the result gets set after the request has been |
| * sent, that result "sticks." That is, if two concurrent threads |
| * race to set the result, the first one wins. The return value |
| * tells the caller whether its result was recorded; if not the |
| * has nothing more to do. |
| */ |
| static bool gb_operation_result_set(struct gb_operation *operation, int result) |
| { |
| int prev; |
| |
| /* Nobody should be setting -EBADR */ |
| if (WARN_ON(result == -EBADR)) |
| return false; |
| |
| /* Are we sending the request message? */ |
| if (result == -EINPROGRESS) { |
| /* Yes, but verify the result has not already been set */ |
| spin_lock_irq(&gb_operations_lock); |
| prev = operation->errno; |
| if (prev == -EBADR) |
| operation->errno = result; |
| spin_unlock_irq(&gb_operations_lock); |
| |
| return !WARN_ON(prev != -EBADR); |
| } |
| |
| /* Trying to set final status; only the first one succeeds */ |
| spin_lock_irq(&gb_operations_lock); |
| prev = operation->errno; |
| if (prev == -EINPROGRESS) |
| operation->errno = result; |
| spin_unlock_irq(&gb_operations_lock); |
| |
| return prev == -EINPROGRESS; |
| } |
| |
| int gb_operation_result(struct gb_operation *operation) |
| { |
| int result = operation->errno; |
| |
| WARN_ON(result == -EINPROGRESS); |
| |
| return result; |
| } |
| |
| static void gb_pending_operation_insert(struct gb_operation *operation) |
| { |
| struct gb_connection *connection = operation->connection; |
| struct gb_operation_msg_hdr *header; |
| |
| /* |
| * Assign the operation's id and move it into its |
| * connection's pending list. |
| */ |
| spin_lock_irq(&gb_operations_lock); |
| operation->id = ++connection->op_cycle; |
| list_move_tail(&operation->links, &connection->pending); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| /* Store the operation id in the request header */ |
| header = operation->request->header; |
| header->operation_id = cpu_to_le16(operation->id); |
| } |
| |
| static void gb_pending_operation_remove(struct gb_operation *operation) |
| { |
| struct gb_connection *connection = operation->connection; |
| |
| /* Take us off of the list of pending operations */ |
| spin_lock_irq(&gb_operations_lock); |
| list_move_tail(&operation->links, &connection->operations); |
| spin_unlock_irq(&gb_operations_lock); |
| } |
| |
| static struct gb_operation * |
| gb_pending_operation_find(struct gb_connection *connection, u16 operation_id) |
| { |
| struct gb_operation *operation; |
| bool found = false; |
| |
| spin_lock_irq(&gb_operations_lock); |
| list_for_each_entry(operation, &connection->pending, links) |
| if (operation->id == operation_id) { |
| found = true; |
| break; |
| } |
| spin_unlock_irq(&gb_operations_lock); |
| |
| return found ? operation : NULL; |
| } |
| |
| static int gb_message_send(struct gb_message *message, gfp_t gfp_mask) |
| { |
| struct gb_connection *connection = message->operation->connection; |
| u16 dest_cport_id = connection->interface_cport_id; |
| int ret = 0; |
| void *cookie; |
| |
| mutex_lock(&gb_message_mutex); |
| cookie = connection->hd->driver->buffer_send(connection->hd, |
| dest_cport_id, |
| message->header, |
| message->size, |
| gfp_mask); |
| if (IS_ERR(cookie)) |
| ret = PTR_ERR(cookie); |
| else |
| message->cookie = cookie; |
| mutex_unlock(&gb_message_mutex); |
| |
| return ret; |
| } |
| |
| /* |
| * Cancel a message whose buffer we have passed to the host device |
| * layer to be sent. |
| */ |
| static void gb_message_cancel(struct gb_message *message) |
| { |
| mutex_lock(&gb_message_mutex); |
| if (message->cookie) { |
| struct greybus_host_device *hd; |
| |
| hd = message->operation->connection->hd; |
| hd->driver->buffer_cancel(message->cookie); |
| } |
| mutex_unlock(&gb_message_mutex); |
| } |
| |
| #if 0 |
| static void gb_operation_request_handle(struct gb_operation *operation) |
| { |
| struct gb_protocol *protocol = operation->connection->protocol; |
| struct gb_operation_msg_hdr *header; |
| |
| header = operation->request->header; |
| |
| /* |
| * If the protocol has no incoming request handler, report |
| * an error and mark the request bad. |
| */ |
| if (protocol->request_recv) { |
| protocol->request_recv(header->type, operation); |
| return; |
| } |
| |
| gb_connection_err(operation->connection, |
| "unexpected incoming request type 0x%02hhx\n", header->type); |
| (void)gb_operation_result_set(operation, -EPROTONOSUPPORT); |
| } |
| #endif |
| |
| /* |
| * Complete an operation in non-atomic context. The operation's |
| * result value should have been set before queueing this. |
| */ |
| static void gb_operation_work(struct work_struct *work) |
| { |
| struct gb_operation *operation; |
| |
| operation = container_of(work, struct gb_operation, work); |
| if (WARN_ON(!operation->callback)) |
| return; |
| |
| operation->callback(operation); |
| operation->callback = NULL; |
| gb_operation_put(operation); |
| } |
| |
| /* |
| * Timeout call for the operation. |
| */ |
| static void gb_operation_timeout(struct work_struct *work) |
| { |
| struct gb_operation *operation; |
| |
| operation = container_of(work, struct gb_operation, timeout_work.work); |
| gb_operation_cancel(operation, -ETIMEDOUT); |
| } |
| |
| /* |
| * Given a pointer to the header in a message sent on a given host |
| * device, return the associated message structure. (This "header" |
| * is just the buffer pointer we supply to the host device for |
| * sending.) |
| */ |
| static struct gb_message * |
| gb_hd_message_find(struct greybus_host_device *hd, void *header) |
| { |
| struct gb_message *message; |
| u8 *result; |
| |
| result = (u8 *)header - hd->buffer_headroom - sizeof(*message); |
| message = (struct gb_message *)result; |
| |
| return message; |
| } |
| |
| /* |
| * Allocate a message to be used for an operation request or |
| * response. For outgoing messages, both types of message contain a |
| * common header, which is filled in here. Incoming requests or |
| * responses also contain the same header, but there's no need to |
| * initialize it here (it'll be overwritten by the incoming |
| * message). |
| * |
| * Our message structure consists of: |
| * message structure |
| * headroom |
| * message header \_ these combined are |
| * message payload / the message size |
| */ |
| static struct gb_message * |
| gb_operation_message_alloc(struct greybus_host_device *hd, u8 type, |
| size_t payload_size, gfp_t gfp_flags) |
| { |
| struct gb_message *message; |
| struct gb_operation_msg_hdr *header; |
| size_t message_size = payload_size + sizeof(*header); |
| size_t size; |
| u8 *buffer; |
| |
| if (hd->buffer_size_max > GB_OPERATION_MESSAGE_SIZE_MAX) { |
| pr_warn("limiting buffer size to %u\n", |
| GB_OPERATION_MESSAGE_SIZE_MAX); |
| hd->buffer_size_max = GB_OPERATION_MESSAGE_SIZE_MAX; |
| } |
| |
| if (message_size > hd->buffer_size_max) |
| return NULL; |
| |
| size = sizeof(*message) + hd->buffer_headroom + message_size; |
| message = kzalloc(size, gfp_flags); |
| if (!message) |
| return NULL; |
| buffer = &message->buffer[0]; |
| header = (struct gb_operation_msg_hdr *)(buffer + hd->buffer_headroom); |
| |
| /* Fill in the header structure */ |
| header->size = cpu_to_le16(message_size); |
| header->operation_id = 0; /* Filled in when submitted */ |
| header->type = type; |
| |
| message->header = header; |
| message->payload = header + 1; |
| message->size = message_size; |
| |
| return message; |
| } |
| |
| static void gb_operation_message_free(struct gb_message *message) |
| { |
| kfree(message); |
| } |
| |
| /* |
| * Map an enum gb_operation_status value (which is represented in a |
| * message as a single byte) to an appropriate Linux negative errno. |
| */ |
| int gb_operation_status_map(u8 status) |
| { |
| switch (status) { |
| case GB_OP_SUCCESS: |
| return 0; |
| case GB_OP_INVALID: |
| return -EINVAL; |
| case GB_OP_NO_MEMORY: |
| return -ENOMEM; |
| case GB_OP_INTERRUPTED: |
| return -EINTR; |
| case GB_OP_RETRY: |
| return -EAGAIN; |
| case GB_OP_PROTOCOL_BAD: |
| return -EPROTONOSUPPORT; |
| case GB_OP_OVERFLOW: |
| return -EMSGSIZE; |
| case GB_OP_TIMEOUT: |
| return -ETIMEDOUT; |
| default: |
| return -EIO; |
| } |
| } |
| |
| /* |
| * Create a Greybus operation to be sent over the given connection. |
| * The request buffer will be big enough for a payload of the given |
| * size. Outgoing requests must specify the size of the response |
| * buffer size, which must be sufficient to hold all expected |
| * response data. |
| * |
| * Incoming requests will supply a response size of 0, and in that |
| * case no response buffer is allocated. (A response always |
| * includes a status byte, so 0 is not a valid size.) Whatever |
| * handles the operation request is responsible for allocating the |
| * response buffer. |
| * |
| * Returns a pointer to the new operation or a null pointer if an |
| * error occurs. |
| */ |
| static struct gb_operation * |
| gb_operation_create_common(struct gb_connection *connection, bool outgoing, |
| u8 type, size_t request_size, |
| size_t response_size) |
| { |
| struct greybus_host_device *hd = connection->hd; |
| struct gb_operation *operation; |
| gfp_t gfp_flags = outgoing ? GFP_KERNEL : GFP_ATOMIC; |
| |
| operation = kmem_cache_zalloc(gb_operation_cache, gfp_flags); |
| if (!operation) |
| return NULL; |
| operation->connection = connection; |
| |
| operation->request = gb_operation_message_alloc(hd, type, request_size, |
| gfp_flags); |
| if (!operation->request) |
| goto err_cache; |
| operation->request->operation = operation; |
| |
| if (outgoing) { |
| type |= GB_OPERATION_TYPE_RESPONSE; |
| operation->response = gb_operation_message_alloc(hd, type, |
| response_size, GFP_KERNEL); |
| if (!operation->response) |
| goto err_request; |
| operation->response->operation = operation; |
| } |
| operation->errno = -EBADR; /* Initial value--means "never set" */ |
| |
| INIT_WORK(&operation->work, gb_operation_work); |
| operation->callback = NULL; /* set at submit time */ |
| init_completion(&operation->completion); |
| INIT_DELAYED_WORK(&operation->timeout_work, gb_operation_timeout); |
| kref_init(&operation->kref); |
| |
| spin_lock_irq(&gb_operations_lock); |
| list_add_tail(&operation->links, &connection->operations); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| return operation; |
| |
| err_request: |
| gb_operation_message_free(operation->request); |
| err_cache: |
| kmem_cache_free(gb_operation_cache, operation); |
| |
| return NULL; |
| } |
| |
| struct gb_operation *gb_operation_create(struct gb_connection *connection, |
| u8 type, size_t request_size, |
| size_t response_size) |
| { |
| return gb_operation_create_common(connection, true, type, |
| request_size, response_size); |
| } |
| |
| static struct gb_operation * |
| gb_operation_create_incoming(struct gb_connection *connection, |
| u8 type, size_t request_size, |
| size_t response_size) |
| { |
| return gb_operation_create_common(connection, false, type, |
| request_size, response_size); |
| } |
| |
| /* |
| * Get an additional reference on an operation. |
| */ |
| void gb_operation_get(struct gb_operation *operation) |
| { |
| kref_get(&operation->kref); |
| } |
| |
| /* |
| * Destroy a previously created operation. |
| */ |
| static void _gb_operation_destroy(struct kref *kref) |
| { |
| struct gb_operation *operation; |
| |
| operation = container_of(kref, struct gb_operation, kref); |
| |
| /* XXX Make sure it's not in flight */ |
| spin_lock_irq(&gb_operations_lock); |
| list_del(&operation->links); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| gb_operation_message_free(operation->response); |
| gb_operation_message_free(operation->request); |
| |
| kmem_cache_free(gb_operation_cache, operation); |
| } |
| |
| /* |
| * Drop a reference on an operation, and destroy it when the last |
| * one is gone. |
| */ |
| void gb_operation_put(struct gb_operation *operation) |
| { |
| if (!WARN_ON(!operation)) |
| kref_put(&operation->kref, _gb_operation_destroy); |
| } |
| |
| /* Tell the requester we're done */ |
| static void gb_operation_sync_callback(struct gb_operation *operation) |
| { |
| complete(&operation->completion); |
| } |
| |
| /* |
| * Send an operation request message. The caller has filled in |
| * any payload so the request message is ready to go. If non-null, |
| * the callback function supplied will be called when the response |
| * message has arrived indicating the operation is complete. In |
| * that case, the callback function is responsible for fetching the |
| * result of the operation using gb_operation_result() if desired, |
| * and dropping the final reference to (i.e., destroying) the |
| * operation. A null callback function is used for a synchronous |
| * request; in that case return from this function won't occur until |
| * the operation is complete. |
| */ |
| int gb_operation_request_send(struct gb_operation *operation, |
| gb_operation_callback callback) |
| { |
| unsigned long timeout; |
| int ret; |
| |
| if (operation->connection->state != GB_CONNECTION_STATE_ENABLED) |
| return -ENOTCONN; |
| |
| /* |
| * First, get an extra reference on the operation. |
| * It'll be dropped when the operation completes. |
| */ |
| gb_operation_get(operation); |
| |
| /* A null callback pointer means synchronous return */ |
| if (callback) |
| operation->callback = callback; |
| else |
| operation->callback = gb_operation_sync_callback; |
| gb_pending_operation_insert(operation); |
| |
| /* |
| * We impose a time limit for requests to complete. We need |
| * to set the timer before we send the request though, so we |
| * don't lose a race with the receipt of the resposne. |
| */ |
| timeout = msecs_to_jiffies(OPERATION_TIMEOUT_DEFAULT); |
| schedule_delayed_work(&operation->timeout_work, timeout); |
| |
| /* All set, send the request */ |
| gb_operation_result_set(operation, -EINPROGRESS); |
| ret = gb_message_send(operation->request, GFP_KERNEL); |
| if (ret || callback) |
| return ret; |
| |
| /* Cancel the operation if interrupted */ |
| ret = wait_for_completion_interruptible(&operation->completion); |
| if (ret < 0) |
| gb_operation_cancel(operation, -ECANCELED); |
| |
| return gb_operation_result(operation); |
| } |
| |
| /* |
| * Send a response for an incoming operation request. |
| */ |
| int gb_operation_response_send(struct gb_operation *operation) |
| { |
| gb_operation_destroy(operation); |
| |
| return 0; |
| } |
| |
| /* |
| * This function is called when a buffer send request has completed. |
| * The "header" is the message header--the beginning of what we |
| * asked to have sent. |
| */ |
| void |
| greybus_data_sent(struct greybus_host_device *hd, void *header, int status) |
| { |
| struct gb_message *message; |
| struct gb_operation *operation; |
| |
| /* XXX Right now we assume we're an outgoing request */ |
| message = gb_hd_message_find(hd, header); |
| |
| /* Record that the message is no longer in flight */ |
| message->cookie = NULL; |
| |
| /* If there's no error, there's really nothing more to do */ |
| if (!status) |
| return; /* Mark it complete? */ |
| |
| operation = message->operation; |
| if (gb_operation_result_set(operation, status)) |
| queue_work(gb_operation_workqueue, &operation->work); |
| } |
| EXPORT_SYMBOL_GPL(greybus_data_sent); |
| |
| /* |
| * We've received data on a connection, and it doesn't look like a |
| * response, so we assume it's a request. |
| * |
| * This is called in interrupt context, so just copy the incoming |
| * data into the request buffer and handle the rest via workqueue. |
| */ |
| void gb_connection_recv_request(struct gb_connection *connection, |
| u16 operation_id, u8 type, void *data, size_t size) |
| { |
| struct gb_operation *operation; |
| |
| operation = gb_operation_create_incoming(connection, type, size, 0); |
| if (!operation) { |
| gb_connection_err(connection, "can't create operation"); |
| return; /* XXX Respond with pre-allocated ENOMEM */ |
| } |
| operation->id = operation_id; |
| memcpy(operation->request->header, data, size); |
| |
| /* XXX Right now this will just complete the operation */ |
| if (gb_operation_result_set(operation, -ENOSYS)) |
| queue_work(gb_operation_workqueue, &operation->work); |
| } |
| |
| /* |
| * We've received data that appears to be an operation response |
| * message. Look up the operation, and record that we've received |
| * its response. |
| * |
| * This is called in interrupt context, so just copy the incoming |
| * data into the response buffer and handle the rest via workqueue. |
| */ |
| static void gb_connection_recv_response(struct gb_connection *connection, |
| u16 operation_id, void *data, size_t size) |
| { |
| struct gb_operation *operation; |
| struct gb_message *message; |
| struct gb_operation_msg_hdr *header; |
| int result; |
| |
| operation = gb_pending_operation_find(connection, operation_id); |
| if (!operation) { |
| gb_connection_err(connection, "operation not found"); |
| return; |
| } |
| |
| cancel_delayed_work(&operation->timeout_work); |
| gb_pending_operation_remove(operation); |
| |
| message = operation->response; |
| if (size == message->size) { |
| /* Transfer the operation result from the response header */ |
| header = message->header; |
| result = gb_operation_status_map(header->result); |
| } else { |
| gb_connection_err(connection, "bad message size (%zu != %zu)", |
| size, message->size); |
| result = -EMSGSIZE; |
| } |
| |
| /* We must ignore the payload if a bad status is returned */ |
| if (!result) |
| memcpy(message->header, data, size); |
| |
| /* The rest will be handled in work queue context */ |
| if (gb_operation_result_set(operation, result)) |
| queue_work(gb_operation_workqueue, &operation->work); |
| } |
| |
| /* |
| * Handle data arriving on a connection. As soon as we return the |
| * supplied data buffer will be reused (so unless we do something |
| * with, it's effectively dropped). |
| */ |
| void gb_connection_recv(struct gb_connection *connection, |
| void *data, size_t size) |
| { |
| struct gb_operation_msg_hdr *header; |
| size_t msg_size; |
| u16 operation_id; |
| |
| if (connection->state != GB_CONNECTION_STATE_ENABLED) { |
| gb_connection_err(connection, "dropping %zu received bytes", |
| size); |
| return; |
| } |
| |
| if (size < sizeof(*header)) { |
| gb_connection_err(connection, "message too small"); |
| return; |
| } |
| |
| header = data; |
| msg_size = (size_t)le16_to_cpu(header->size); |
| if (msg_size > size) { |
| gb_connection_err(connection, "incomplete message"); |
| return; /* XXX Should still complete operation */ |
| } |
| |
| operation_id = le16_to_cpu(header->operation_id); |
| if (header->type & GB_OPERATION_TYPE_RESPONSE) |
| gb_connection_recv_response(connection, operation_id, |
| data, msg_size); |
| else |
| gb_connection_recv_request(connection, operation_id, |
| header->type, data, msg_size); |
| } |
| |
| /* |
| * Cancel an operation, and record the given error to indicate why. |
| */ |
| void gb_operation_cancel(struct gb_operation *operation, int errno) |
| { |
| if (gb_operation_result_set(operation, errno)) { |
| gb_message_cancel(operation->request); |
| gb_message_cancel(operation->response); |
| } |
| } |
| |
| /** |
| * gb_operation_sync: implement a "simple" synchronous gb operation. |
| * @connection: the Greybus connection to send this to |
| * @type: the type of operation to send |
| * @request: pointer to a memory buffer to copy the request from |
| * @request_size: size of @request |
| * @response: pointer to a memory buffer to copy the response to |
| * @response_size: the size of @response. |
| * |
| * This function implements a simple synchronous Greybus operation. It sends |
| * the provided operation request and waits (sleeps) until the corresponding |
| * operation response message has been successfully received, or an error |
| * occurs. @request and @response are buffers to hold the request and response |
| * data respectively, and if they are not NULL, their size must be specified in |
| * @request_size and @response_size. |
| * |
| * If a response payload is to come back, and @response is not NULL, |
| * @response_size number of bytes will be copied into @response if the operation |
| * is successful. |
| * |
| * If there is an error, the response buffer is left alone. |
| */ |
| int gb_operation_sync(struct gb_connection *connection, int type, |
| void *request, int request_size, |
| void *response, int response_size) |
| { |
| struct gb_operation *operation; |
| int ret; |
| |
| if ((response_size && !response) || |
| (request_size && !request)) |
| return -EINVAL; |
| |
| operation = gb_operation_create(connection, type, |
| request_size, response_size); |
| if (!operation) |
| return -ENOMEM; |
| |
| if (request_size) |
| memcpy(&operation->request->payload, request, request_size); |
| |
| /* Synchronous operation--no callback */ |
| ret = gb_operation_request_send(operation, NULL); |
| if (ret) |
| pr_err("version operation failed (%d)\n", ret); |
| else |
| if (response_size) |
| memcpy(response, operation->response->payload, |
| response_size); |
| gb_operation_destroy(operation); |
| |
| return ret; |
| } |
| |
| int gb_operation_init(void) |
| { |
| BUILD_BUG_ON(GB_OPERATION_MESSAGE_SIZE_MAX > |
| U16_MAX - sizeof(struct gb_operation_msg_hdr)); |
| |
| gb_operation_cache = kmem_cache_create("gb_operation_cache", |
| sizeof(struct gb_operation), 0, 0, NULL); |
| if (!gb_operation_cache) |
| return -ENOMEM; |
| |
| gb_operation_workqueue = alloc_workqueue("greybus_operation", 0, 1); |
| if (!gb_operation_workqueue) { |
| kmem_cache_destroy(gb_operation_cache); |
| gb_operation_cache = NULL; |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| void gb_operation_exit(void) |
| { |
| destroy_workqueue(gb_operation_workqueue); |
| gb_operation_workqueue = NULL; |
| kmem_cache_destroy(gb_operation_cache); |
| gb_operation_cache = NULL; |
| } |