diff options
Diffstat (limited to 'include/net/9p/client.h')
| -rw-r--r-- | include/net/9p/client.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/include/net/9p/client.h b/include/net/9p/client.h index c35fb548e7c..140cf1d5845 100644 --- a/include/net/9p/client.h +++ b/include/net/9p/client.h @@ -26,6 +26,9 @@ #ifndef NET_9P_CLIENT_H #define NET_9P_CLIENT_H +/* Number of requests per row */ +#define P9_ROW_MAXTAG 255 + /** * enum p9_trans_status - different states of underlying transports * @Connected: transport is connected and healthy @@ -43,6 +46,62 @@ enum p9_trans_status { }; /** + * enum p9_req_status_t - virtio request status + * @REQ_STATUS_IDLE: request slot unused + * @REQ_STATUS_ALLOC: request has been allocated but not sent + * @REQ_STATUS_SENT: request sent to server + * @REQ_STATUS_FLSH: a flush has been sent for this request + * @REQ_STATUS_RCVD: response received from server + * @REQ_STATUS_FLSHD: request has been flushed + * @REQ_STATUS_ERR: request encountered an error on the client side + * + * The @REQ_STATUS_IDLE state is used to mark a request slot as unused + * but use is actually tracked by the idpool structure which handles tag + * id allocation. + * + */ + +enum p9_req_status_t { + REQ_STATUS_IDLE, + REQ_STATUS_ALLOC, + REQ_STATUS_SENT, + REQ_STATUS_FLSH, + REQ_STATUS_RCVD, + REQ_STATUS_FLSHD, + REQ_STATUS_ERROR, +}; + +/** + * struct p9_req_t - request slots + * @status: status of this request slot + * @t_err: transport error + * @wq: wait_queue for the client to block on for this request + * @tc: the request fcall structure + * @rc: the response fcall structure + * @aux: transport specific data (provided for trans_fd migration) + * + * Transport use an array to track outstanding requests + * instead of a list. While this may incurr overhead during initial + * allocation or expansion, it makes request lookup much easier as the + * tag id is a index into an array. (We use tag+1 so that we can accomodate + * the -1 tag for the T_VERSION request). + * This also has the nice effect of only having to allocate wait_queues + * once, instead of constantly allocating and freeing them. Its possible + * other resources could benefit from this scheme as well. + * + */ + +struct p9_req_t { + int status; + int t_err; + wait_queue_head_t *wq; + struct p9_fcall *tc; + struct p9_fcall *rc; + u16 flush_tag; + void *aux; +}; + +/** * struct p9_client - per client instance state * @lock: protect @fidlist * @msize: maximum data size negotiated by protocol @@ -52,9 +111,20 @@ enum p9_trans_status { * @conn: connection state information used by trans_fd * @fidpool: fid handle accounting for session * @fidlist: List of active fid handles + * @tagpool - transaction id accounting for session + * @reqs - 2D array of requests + * @max_tag - current maximum tag id allocated * * The client structure is used to keep track of various per-client * state that has been instantiated. + * In order to minimize per-transaction overhead we use a + * simple array to lookup requests instead of a hash table + * or linked list. In order to support larger number of + * transactions, we make this a 2D array, allocating new rows + * when we need to grow the total number of the transactions. + * + * Each row is 256 requests and we'll support up to 256 rows for + * a total of 64k concurrent requests per session. * * Bugs: duplicated data and potentially unnecessary elements. */ @@ -70,6 +140,10 @@ struct p9_client { struct p9_idpool *fidpool; struct list_head fidlist; + + struct p9_idpool *tagpool; + struct p9_req_t *reqs[P9_ROW_MAXTAG]; + int max_tag; }; /** @@ -131,4 +205,7 @@ struct p9_stat *p9_client_stat(struct p9_fid *fid); int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst); struct p9_stat *p9_client_dirread(struct p9_fid *fid, u64 offset); +struct p9_req_t *p9_tag_alloc(struct p9_client *, u16); +struct p9_req_t *p9_tag_lookup(struct p9_client *, u16); + #endif /* NET_9P_CLIENT_H */ |