mpm_event,mod_http2,mod_status: Follow up to r1918257: CONN_STATE_ASYNC_WAITIO.

Per discussion on PR #449, have a separate state for returning the connection
to the MPM to wait for an IO (namely CONN_STATE_ASYNC_WAITIO), rather than
(ab)using CONN_STATE_PROCESSING.

This removes the need for AGAIN added in r1918257 (for now), and AP_MPMQ_CAN_AGAIN
is renamed to AP_MPMQ_CAN_WAITIO.

This is also the state that mod_status accounts for, so rename ->processing
to ->wait_io in process_score (shows as "wait-io" in mod_status and mod_lua).



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1918482 13f79535-47bb-0310-9956-ffa450edef68

4 files changed, 13 insertions, 15 deletions

diff --git a/include/ap_mmn.h b/include/ap_mmn.h
index fcf98e8908..3bc51334e7 100644
--- a/include/ap_mmn.h
+++ b/include/ap_mmn.h
@@ -723,9 +723,10 @@
  * 20211221.17 (2.5.1-dev) Add ap_proxy_worker_get_name()
  * 20211221.18 (2.5.1-dev) Add ap_regexec_ex()
  * 20211221.19 (2.5.1-dev) Add AP_REG_NOTEMPTY_ATSTART
- * 20211221.20 (2.5.1-dev) Add CONN_STATE_KEEPALIVE and CONN_STATE_PROCESSING
- * 20211221.21 (2.5.1-dev) Add processing field struct process_score
- * 20211221.22 (2.5.1-dev) Add AGAIN, AP_MPMQ_CAN_AGAIN.
+ * 20211221.20 (2.5.1-dev) Add CONN_STATE_ASYNC_WAITIO, CONN_STATE_KEEPALIVE
+ *                         and CONN_STATE_PROCESSING
+ * 20211221.21 (2.5.1-dev) Add wait_io field to struct process_score
+ * 20211221.22 (2.5.1-dev) Add AP_MPMQ_CAN_WAITIO
  */
 
 #define MODULE_MAGIC_COOKIE 0x41503235UL /* "AP25" */
diff --git a/include/ap_mpm.h b/include/ap_mpm.h
index 82075a4488..f2fd436d50 100644
--- a/include/ap_mpm.h
+++ b/include/ap_mpm.h
@@ -182,8 +182,8 @@ AP_DECLARE(apr_status_t) ap_os_create_privileged_process(
 #define AP_MPMQ_CAN_SUSPEND          17
 /** MPM supports additional pollfds */
 #define AP_MPMQ_CAN_POLL             18
-/** MPM reacts to AGAIN response */
-#define AP_MPMQ_CAN_AGAIN            19
+/** MPM supports CONN_STATE_ASYNC_WAITIO */
+#define AP_MPMQ_CAN_WAITIO           19
 /** @} */
 
 /**
diff --git a/include/httpd.h b/include/httpd.h
index 99a3cf31a7..9782a8ad82 100644
--- a/include/httpd.h
+++ b/include/httpd.h
@@ -465,9 +465,6 @@ AP_DECLARE(const char *) ap_get_server_built(void);
                          */
 #define SUSPENDED   -3  /**< Module will handle the remainder of the request.
                          *   The core will never invoke the request again */
-#define AGAIN       -4  /**< Module wants to be called again when more
-                         *   data is available.
-                         */
 
 /** Returned by the bottom-most filter if no data was written.
  *  @see ap_pass_brigade(). */
@@ -1322,11 +1319,7 @@ struct conn_slave_rec {
  */
 typedef enum  {
     CONN_STATE_KEEPALIVE,           /* Kept alive in the MPM (using KeepAliveTimeout) */
-    CONN_STATE_PROCESSING,          /* Processed by process_connection() hooks, returning
-                                     * AGAIN to the MPM in this state will make it wait for
-                                     * the connection to be readable or writable according to
-                                     * CONN_SENSE_WANT_READ or CONN_SENSE_WANT_WRITE respectively,
-                                     * where Timeout applies */
+    CONN_STATE_PROCESSING,          /* Processed by process_connection hooks */
     CONN_STATE_HANDLER,             /* Processed by the modules handlers */
     CONN_STATE_WRITE_COMPLETION,    /* Flushed by the MPM before entering CONN_STATE_KEEPALIVE */
     CONN_STATE_SUSPENDED,           /* Suspended in the MPM until ap_run_resume_suspended() */
@@ -1334,6 +1327,11 @@ typedef enum  {
     CONN_STATE_LINGER_NORMAL,       /* MPM has started lingering close with normal timeout */
     CONN_STATE_LINGER_SHORT,        /* MPM has started lingering close with short timeout */
 
+    CONN_STATE_ASYNC_WAITIO,        /* Returning this state to the MPM will make it wait for
+                                     * the connection to be readable or writable according to
+                                     * c->cs->sense (resp. CONN_SENSE_WANT_READ or _WRITE),
+                                     * using the configured Timeout */
+
     CONN_STATE_NUM,                 /* Number of states (keep here before aliases) */
 
     /* Aliases (legacy) */
diff --git a/include/scoreboard.h b/include/scoreboard.h
index d604b875df..25d19f0353 100644
--- a/include/scoreboard.h
+++ b/include/scoreboard.h
@@ -148,8 +148,7 @@ struct process_score {
     apr_uint32_t lingering_close;   /* async connections in lingering close */
     apr_uint32_t keep_alive;        /* async connections in keep alive */
     apr_uint32_t suspended;         /* connections suspended by some module */
-    apr_uint32_t processing;        /* async connections in processing (returned
-                                       to the MPM for POLLIN/POLLOUT) */
+    apr_uint32_t wait_io;           /* async connections waiting an IO in the MPM */
 };
 
 /* Scoreboard is now in 'local' memory, since it isn't updated once created,