MEDIUM: connection: get rid of CO_FL_CURR_* flags
These ones used to serve as a set of switches between CO_FL_SOCK_* and
CO_FL_XPRT_*, and now that the SOCK layer is gone, they're always a
copy of the last know CO_FL_XPRT_* ones that is resynchronized before
I/O events by calling conn_refresh_polling_flags(), and that are pushed
back to FDs when detecting changes with conn_xprt_polling_changes().
While these functions are not particularly heavy, what they do is
totally redundant by now because the fd_want_*/fd_stop_*() actions
already perform test-and-set operations to decide to create an entry
or not, so they do the exact same thing that is done by
conn_xprt_polling_changes(). As such it is pointless to call that
one, and given that the only reason to keep CO_FL_CURR_* is to detect
changes there, we can now remove them.
Even if this does only save very few cycles, this removes a significant
complexity that has been responsible for many bugs in the past, including
the last one affecting FreeBSD.
All tests look good, and no performance regressions were observed.
diff --git a/contrib/debug/flags.c b/contrib/debug/flags.c
index 08ca054..585dea6 100644
--- a/contrib/debug/flags.c
+++ b/contrib/debug/flags.c
@@ -139,9 +139,7 @@
SHOW_FLAG(f, CO_FL_WILL_UPDATE);
SHOW_FLAG(f, CO_FL_XPRT_READY);
SHOW_FLAG(f, CO_FL_CTRL_READY);
- SHOW_FLAG(f, CO_FL_CURR_WR_ENA);
SHOW_FLAG(f, CO_FL_XPRT_WR_ENA);
- SHOW_FLAG(f, CO_FL_CURR_RD_ENA);
SHOW_FLAG(f, CO_FL_XPRT_RD_ENA);
if (f) {
diff --git a/include/proto/connection.h b/include/proto/connection.h
index cd6e62d..dd37822 100644
--- a/include/proto/connection.h
+++ b/include/proto/connection.h
@@ -161,55 +161,12 @@
}
/* Update polling on connection <c>'s file descriptor depending on its current
- * state as reported in the connection's CO_FL_CURR_* flags, reports of EAGAIN
- * in CO_FL_WAIT_*, and the upper layer expectations indicated by CO_FL_XPRT_*.
- * The connection flags are updated with the new flags at the end of the
- * operation. Polling is totally disabled if an error was reported.
+ * state as reported in the connection's CO_FL_XPRT_* flags. The connection
+ * flags are updated with the new flags at the end of the operation. Polling
+ * is totally disabled if an error was reported.
*/
void conn_update_xprt_polling(struct connection *c);
-/* Refresh the connection's polling flags from its file descriptor status.
- * This should be called at the beginning of a connection handler. It does
- * nothing if CO_FL_WILL_UPDATE is present, indicating that an upper caller
- * has already done it.
- */
-static inline void conn_refresh_polling_flags(struct connection *conn)
-{
- if (conn_ctrl_ready(conn) && !(conn->flags & CO_FL_WILL_UPDATE)) {
- unsigned int flags = conn->flags;
-
- flags &= ~(CO_FL_CURR_RD_ENA | CO_FL_CURR_WR_ENA);
- if (fd_recv_active(conn->handle.fd))
- flags |= CO_FL_CURR_RD_ENA;
- if (fd_send_active(conn->handle.fd))
- flags |= CO_FL_CURR_WR_ENA;
- conn->flags = flags;
- }
-}
-
-/* inspects c->flags and returns non-zero if XPRT ENA changes from the CURR ENA
- * or if the WAIT flags are set with their respective ENA flags. Additionally,
- * non-zero is also returned if an error was reported on the connection. This
- * function is used quite often and is inlined. In order to proceed optimally
- * with very little code and CPU cycles, the bits are arranged so that a change
- * can be detected by a few left shifts, a xor, and a mask. These operations
- * detect when W&D are both enabled for either direction, when C&D differ for
- * either direction and when Error is set. The trick consists in first keeping
- * only the bits we're interested in, since they don't collide when shifted,
- * and to perform the AND at the end. In practice, the compiler is able to
- * replace the last AND with a TEST in boolean conditions. This results in
- * checks that are done in 4-6 cycles and less than 30 bytes.
- */
-static inline unsigned int conn_xprt_polling_changes(const struct connection *c)
-{
- unsigned int f = c->flags;
- f &= CO_FL_XPRT_WR_ENA | CO_FL_XPRT_RD_ENA | CO_FL_CURR_WR_ENA |
- CO_FL_CURR_RD_ENA | CO_FL_ERROR;
-
- f = (f ^ (f << 1)) & (CO_FL_CURR_WR_ENA|CO_FL_CURR_RD_ENA); /* test C ^ D */
- return f & (CO_FL_CURR_WR_ENA | CO_FL_CURR_RD_ENA | CO_FL_ERROR);
-}
-
/* Automatically updates polling on connection <c> depending on the XPRT flags.
* It does nothing if CO_FL_WILL_UPDATE is present, indicating that an upper
* caller is going to do it again later.
@@ -217,8 +174,7 @@
static inline void conn_cond_update_xprt_polling(struct connection *c)
{
if (!(c->flags & CO_FL_WILL_UPDATE))
- if (conn_xprt_polling_changes(c))
- conn_update_xprt_polling(c);
+ conn_update_xprt_polling(c);
}
/* Stop all polling on the fd. This might be used when an error is encountered
@@ -228,8 +184,7 @@
*/
static inline void conn_stop_polling(struct connection *c)
{
- c->flags &= ~(CO_FL_CURR_RD_ENA | CO_FL_CURR_WR_ENA |
- CO_FL_XPRT_RD_ENA | CO_FL_XPRT_WR_ENA);
+ c->flags &= ~(CO_FL_XPRT_RD_ENA | CO_FL_XPRT_WR_ENA);
if (!(c->flags & CO_FL_WILL_UPDATE) && conn_ctrl_ready(c))
fd_stop_both(c->handle.fd);
}
@@ -245,10 +200,8 @@
{
if (unlikely(c->flags & CO_FL_ERROR))
conn_stop_polling(c);
- else if (!(c->flags & CO_FL_WILL_UPDATE)) {
- if (conn_xprt_polling_changes(c))
- conn_update_xprt_polling(c);
- }
+ else if (!(c->flags & CO_FL_WILL_UPDATE))
+ conn_update_xprt_polling(c);
}
/***** Event manipulation primitives for use by DATA I/O callbacks *****/
@@ -333,7 +286,6 @@
static inline void conn_sock_shutw(struct connection *c, int clean)
{
c->flags |= CO_FL_SOCK_WR_SH;
- conn_refresh_polling_flags(c);
__conn_xprt_stop_send(c);
conn_cond_update_xprt_polling(c);
diff --git a/include/types/connection.h b/include/types/connection.h
index 3f9fb3c..d5852aa 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -118,17 +118,16 @@
CS_SHW_SILENT = 1, /* imminent close, don't notify peer */
};
-/* For each direction, we have a CO_FL_{SOCK,DATA}_<DIR>_ENA flag, which
+/* For each direction, we have a CO_FL_XPRT_<DIR>_ENA flag, which
* indicates if read or write is desired in that direction for the respective
* layers. The current status corresponding to the current layer being used is
- * remembered in the CO_FL_CURR_<DIR>_ENA flag. The need to poll (ie receipt of
+ * remembered in the CO_FL_XPRT_<DIR>_ENA flag. The need to poll (ie receipt of
* EAGAIN) is remembered at the file descriptor level so that even when the
* activity is stopped and restarted, we still remember whether it was needed
* to poll before attempting the I/O.
*
- * The CO_FL_CURR_<DIR>_ENA flag is set from the FD status in
- * conn_refresh_polling_flags(). The FD state is updated according to these
- * flags in conn_cond_update_polling().
+ * The FD state is updated according to CO_FL_XPRT_<DIR>_ENA in
+ * conn_cond_update_polling().
*/
/* flags for use in connection->flags */
@@ -136,15 +135,13 @@
CO_FL_NONE = 0x00000000, /* Just for initialization purposes */
/* Do not change these values without updating conn_*_poll_changes() ! */
- /* unusued : 0x00000001 */
+ /* unused : 0x00000001 */
CO_FL_XPRT_RD_ENA = 0x00000002, /* receiving data is allowed */
- CO_FL_CURR_RD_ENA = 0x00000004, /* receiving is currently allowed */
- /* unused : 0x00000008 */
+ /* unused : 0x00000004, 0x00000008 */
/* unused : 0x00000010 */
CO_FL_XPRT_WR_ENA = 0x00000020, /* sending data is desired */
- CO_FL_CURR_WR_ENA = 0x00000040, /* sending is currently desired */
- /* unused : 0x00000080 */
+ /* unused : 0x00000040, 0x00000080 */
/* These flags indicate whether the Control and Transport layers are initialized */
CO_FL_CTRL_READY = 0x00000100, /* FD was registered, fd_delete() needed */
diff --git a/src/connection.c b/src/connection.c
index 3337538..bf55f86 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -55,7 +55,6 @@
return;
}
- conn_refresh_polling_flags(conn);
conn->flags |= CO_FL_WILL_UPDATE;
flags = conn->flags & ~CO_FL_ERROR; /* ensure to call the wake handler upon error */
@@ -150,10 +149,9 @@
}
/* Update polling on connection <c>'s file descriptor depending on its current
- * state as reported in the connection's CO_FL_CURR_* flags, reports of EAGAIN
- * in CO_FL_WAIT_*, and the data layer expectations indicated by CO_FL_XPRT_*.
- * The connection flags are updated with the new flags at the end of the
- * operation. Polling is totally disabled if an error was reported.
+ * state as reported in the connection's CO_FL_XPRT_* flags. The connection
+ * flags are updated with the new flags at the end of the operation. Polling
+ * is totally disabled if an error was reported.
*/
void conn_update_xprt_polling(struct connection *c)
{
@@ -163,25 +161,16 @@
return;
/* update read status if needed */
- if (unlikely((f & (CO_FL_CURR_RD_ENA|CO_FL_XPRT_RD_ENA)) == CO_FL_XPRT_RD_ENA)) {
+ if (f & CO_FL_XPRT_RD_ENA)
fd_want_recv(c->handle.fd);
- f |= CO_FL_CURR_RD_ENA;
- }
- else if (unlikely((f & (CO_FL_CURR_RD_ENA|CO_FL_XPRT_RD_ENA)) == CO_FL_CURR_RD_ENA)) {
+ else
fd_stop_recv(c->handle.fd);
- f &= ~CO_FL_CURR_RD_ENA;
- }
/* update write status if needed */
- if (unlikely((f & (CO_FL_CURR_WR_ENA|CO_FL_XPRT_WR_ENA)) == CO_FL_XPRT_WR_ENA)) {
+ if (f & CO_FL_XPRT_WR_ENA)
fd_want_send(c->handle.fd);
- f |= CO_FL_CURR_WR_ENA;
- }
- else if (unlikely((f & (CO_FL_CURR_WR_ENA|CO_FL_XPRT_WR_ENA)) == CO_FL_CURR_WR_ENA)) {
+ else
fd_stop_send(c->handle.fd);
- f &= ~CO_FL_CURR_WR_ENA;
- }
- c->flags = f;
}
/* This is the callback which is set when a connection establishment is pending
diff --git a/src/raw_sock.c b/src/raw_sock.c
index 63c8f6f..91a3593 100644
--- a/src/raw_sock.c
+++ b/src/raw_sock.c
@@ -73,7 +73,6 @@
return 0;
conn->flags &= ~CO_FL_WAIT_ROOM;
- conn_refresh_polling_flags(conn);
errno = 0;
/* Under Linux, if FD_POLL_HUP is set, we have reached the end.
@@ -186,7 +185,6 @@
if (!fd_send_ready(conn->handle.fd))
return 0;
- conn_refresh_polling_flags(conn);
done = 0;
while (pipe->data) {
ret = splice(pipe->cons, NULL, conn->handle.fd, NULL, pipe->data,
@@ -241,7 +239,6 @@
return 0;
conn->flags &= ~CO_FL_WAIT_ROOM;
- conn_refresh_polling_flags(conn);
errno = 0;
if (unlikely(!(fdtab[conn->handle.fd].ev & FD_POLL_IN))) {
@@ -354,7 +351,6 @@
if (!fd_send_ready(conn->handle.fd))
return 0;
- conn_refresh_polling_flags(conn);
done = 0;
/* send the largest possible block. For this we perform only one call
* to send() unless the buffer wraps and we exactly fill the first hunk,
@@ -380,10 +376,8 @@
/* if the system buffer is full, don't insist */
if (ret < try)
break;
- if (!count) {
+ if (!count)
conn_xprt_stop_send(conn);
- conn_refresh_polling_flags(conn);
- }
}
else if (ret == 0 || errno == EAGAIN || errno == ENOTCONN || errno == EINPROGRESS) {
/* nothing written, we need to poll for write first */
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index ff8af23..f2bce21 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -6505,8 +6505,6 @@
ssize_t ret;
size_t try, done = 0;
- conn_refresh_polling_flags(conn);
-
if (!ctx)
goto out_error;
@@ -6631,7 +6629,6 @@
size_t try, done;
done = 0;
- conn_refresh_polling_flags(conn);
if (!ctx)
goto out_error;