[Qemu-devel] [RFC][PATCH v6 01/23] Move code related to fd handlers into utility functions

[Michael Roth <mdroth@linux.vnet.ibm.com>]

This allows us to implement an i/o loop outside of vl.c that can
interact with objects that use qemu_set_fd_handler()

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 Makefile.objs |    2 +-
 qemu-char.h   |    4 ++
 qemu-ioh.c    |  115 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qemu-ioh.h    |   34 +++++++++++++++++
 vl.c          |   86 ++++++++----------------------------------
 5 files changed, 170 insertions(+), 71 deletions(-)
 create mode 100644 qemu-ioh.c
 create mode 100644 qemu-ioh.h

diff --git a/Makefile.objs b/Makefile.objs
index c3e52c5..0078921 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -14,7 +14,7 @@ oslib-obj-$(CONFIG_POSIX) += oslib-posix.o
 # block-obj-y is code used by both qemu system emulation and qemu-img
 
 block-obj-y = cutils.o cache-utils.o qemu-malloc.o qemu-option.o module.o
-block-obj-y += nbd.o block.o aio.o aes.o qemu-config.o
+block-obj-y += nbd.o block.o aio.o aes.o qemu-config.o qemu-ioh.o
 block-obj-$(CONFIG_POSIX) += posix-aio-compat.o
 block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
 
diff --git a/qemu-char.h b/qemu-char.h
index e6ee6c4..7d0794a 100644
--- a/qemu-char.h
+++ b/qemu-char.h
@@ -7,6 +7,7 @@
 #include "qemu-config.h"
 #include "qobject.h"
 #include "qstring.h"
+#include "qemu-ioh.h"
 
 /* character device */
 
@@ -118,4 +119,7 @@ int qemu_set_fd_handler(int fd,
                         IOHandler *fd_read,
                         IOHandler *fd_write,
                         void *opaque);
+void qemu_get_fdset(int *nfds, fd_set *rfds, fd_set *wfds, fd_set *xfds);
+void qemu_process_fd_handlers(const fd_set *rfds, const fd_set *wfds,
+                              const fd_set *xfds);
 #endif
diff --git a/qemu-ioh.c b/qemu-ioh.c
new file mode 100644
index 0000000..cc71470
--- /dev/null
+++ b/qemu-ioh.c
@@ -0,0 +1,115 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu-ioh.h"
+#include "qlist.h"
+
+/* XXX: fd_read_poll should be suppressed, but an API change is
+   necessary in the character devices to suppress fd_can_read(). */
+int qemu_set_fd_handler3(void *ioh_record_list,
+                         int fd,
+                         IOCanReadHandler *fd_read_poll,
+                         IOHandler *fd_read,
+                         IOHandler *fd_write,
+                         void *opaque)
+{
+    QLIST_HEAD(, IOHandlerRecord) *io_handlers_ptr = ioh_record_list;
+    IOHandlerRecord *ioh;
+
+    if (!fd_read && !fd_write) {
+        QLIST_FOREACH(ioh, io_handlers_ptr, next) {
+            if (ioh->fd == fd) {
+                ioh->deleted = 1;
+                break;
+            }
+        }
+    } else {
+        QLIST_FOREACH(ioh, io_handlers_ptr, next) {
+            if (ioh->fd == fd)
+                goto found;
+        }
+        ioh = qemu_mallocz(sizeof(IOHandlerRecord));
+        QLIST_INSERT_HEAD(io_handlers_ptr, ioh, next);
+    found:
+        ioh->fd = fd;
+        ioh->fd_read_poll = fd_read_poll;
+        ioh->fd_read = fd_read;
+        ioh->fd_write = fd_write;
+        ioh->opaque = opaque;
+        ioh->deleted = 0;
+    }
+    return 0;
+}
+
+/* add entries from ioh record list to fd sets. nfds and fd sets
+ * should be cleared/reset by caller if desired. set a particular
+ * fdset to NULL to ignore fd events of that type
+ */
+void qemu_get_fdset2(void *ioh_record_list, int *nfds, fd_set *rfds,
+                     fd_set *wfds, fd_set *xfds)
+{
+    QLIST_HEAD(, IOHandlerRecord) *io_handlers = ioh_record_list;
+    IOHandlerRecord *ioh;
+
+    QLIST_FOREACH(ioh, io_handlers, next) {
+        if (ioh->deleted)
+            continue;
+        if ((rfds != NULL && ioh->fd_read) &&
+            (!ioh->fd_read_poll ||
+             ioh->fd_read_poll(ioh->opaque) != 0)) {
+            FD_SET(ioh->fd, rfds);
+            if (ioh->fd > *nfds)
+                *nfds = ioh->fd;
+        }
+        if (wfds != NULL && ioh->fd_write) {
+            FD_SET(ioh->fd, wfds);
+            if (ioh->fd > *nfds)
+                *nfds = ioh->fd;
+        }
+    }
+}
+
+/* execute registered handlers for r/w events in the provided fdsets. unset
+ * handlers are cleaned up here as well
+ */
+void qemu_process_fd_handlers2(void *ioh_record_list, const fd_set *rfds,
+                               const fd_set *wfds, const fd_set *xfds)
+{
+    QLIST_HEAD(, IOHandlerRecord) *io_handlers = ioh_record_list;
+    IOHandlerRecord *ioh, *pioh;
+
+    QLIST_FOREACH_SAFE(ioh, io_handlers, next, pioh) {
+        if (!ioh->deleted && ioh->fd_read && FD_ISSET(ioh->fd, rfds)) {
+            ioh->fd_read(ioh->opaque);
+        }
+        if (!ioh->deleted && ioh->fd_write && FD_ISSET(ioh->fd, wfds)) {
+            ioh->fd_write(ioh->opaque);
+        }
+
+        /* Do this last in case read/write handlers marked it for deletion */
+        if (ioh->deleted) {
+            QLIST_REMOVE(ioh, next);
+            qemu_free(ioh);
+        }
+    }
+}
diff --git a/qemu-ioh.h b/qemu-ioh.h
new file mode 100644
index 0000000..7c6e833
--- /dev/null
+++ b/qemu-ioh.h
@@ -0,0 +1,34 @@
+#ifndef QEMU_IOH_H
+#define QEMU_IOH_H
+
+#include "qemu-common.h"
+#include "qlist.h"
+
+/* common i/o loop definitions */
+
+typedef struct IOHandlerRecord {
+    int fd;
+    IOCanReadHandler *fd_read_poll;
+    IOHandler *fd_read;
+    IOHandler *fd_write;
+    int deleted;
+    void *opaque;
+    /* temporary data */
+    struct pollfd *ufd;
+    QLIST_ENTRY(IOHandlerRecord) next;
+} IOHandlerRecord;
+
+/* XXX: fd_read_poll should be suppressed, but an API change is
+   necessary in the character devices to suppress fd_can_read(). */
+int qemu_set_fd_handler3(void *io_handlers_ptr,
+                         int fd,
+                         IOCanReadHandler *fd_read_poll,
+                         IOHandler *fd_read,
+                         IOHandler *fd_write,
+                         void *opaque);
+void qemu_get_fdset2(void *ioh_record_list, int *nfds, fd_set *rfds,
+                     fd_set *wfds, fd_set *xfds);
+void qemu_process_fd_handlers2(void *ioh_record_list, const fd_set *rfds,
+                               const fd_set *wfds, const fd_set *xfds);
+
+#endif
diff --git a/vl.c b/vl.c
index 0292184..d3bdfec 100644
--- a/vl.c
+++ b/vl.c
@@ -148,6 +148,7 @@ int main(int argc, char **argv)
 #include "qemu-config.h"
 #include "qemu-objects.h"
 #include "qemu-options.h"
+#include "qemu-ioh.h"
 #ifdef CONFIG_VIRTFS
 #include "fsdev/qemu-fsdev.h"
 #endif
@@ -1007,18 +1008,6 @@ void pcmcia_info(Monitor *mon)
 /***********************************************************/
 /* I/O handling */
 
-typedef struct IOHandlerRecord {
-    int fd;
-    IOCanReadHandler *fd_read_poll;
-    IOHandler *fd_read;
-    IOHandler *fd_write;
-    int deleted;
-    void *opaque;
-    /* temporary data */
-    struct pollfd *ufd;
-    QLIST_ENTRY(IOHandlerRecord) next;
-} IOHandlerRecord;
-
 static QLIST_HEAD(, IOHandlerRecord) io_handlers =
     QLIST_HEAD_INITIALIZER(io_handlers);
 
@@ -1031,31 +1020,8 @@ int qemu_set_fd_handler2(int fd,
                          IOHandler *fd_write,
                          void *opaque)
 {
-    IOHandlerRecord *ioh;
-
-    if (!fd_read && !fd_write) {
-        QLIST_FOREACH(ioh, &io_handlers, next) {
-            if (ioh->fd == fd) {
-                ioh->deleted = 1;
-                break;
-            }
-        }
-    } else {
-        QLIST_FOREACH(ioh, &io_handlers, next) {
-            if (ioh->fd == fd)
-                goto found;
-        }
-        ioh = qemu_mallocz(sizeof(IOHandlerRecord));
-        QLIST_INSERT_HEAD(&io_handlers, ioh, next);
-    found:
-        ioh->fd = fd;
-        ioh->fd_read_poll = fd_read_poll;
-        ioh->fd_read = fd_read;
-        ioh->fd_write = fd_write;
-        ioh->opaque = opaque;
-        ioh->deleted = 0;
-    }
-    return 0;
+    return qemu_set_fd_handler3(&io_handlers, fd, fd_read_poll, fd_read,
+                                fd_write, opaque);
 }
 
 int qemu_set_fd_handler(int fd,
@@ -1066,6 +1032,17 @@ int qemu_set_fd_handler(int fd,
     return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque);
 }
 
+void qemu_get_fdset(int *nfds, fd_set *rfds, fd_set *wfds, fd_set *xfds)
+{
+    return qemu_get_fdset2(&io_handlers, nfds, rfds, wfds, xfds);
+}
+
+void qemu_process_fd_handlers(const fd_set *rfds, const fd_set *wfds,
+                              const fd_set *xfds)
+{
+    return qemu_process_fd_handlers2(&io_handlers, rfds, wfds, xfds);
+}
+
 /***********************************************************/
 /* machine registration */
 
@@ -1295,7 +1272,6 @@ void qemu_system_powerdown_request(void)
 
 void main_loop_wait(int nonblocking)
 {
-    IOHandlerRecord *ioh;
     fd_set rfds, wfds, xfds;
     int ret, nfds;
     struct timeval tv;
@@ -1316,22 +1292,7 @@ void main_loop_wait(int nonblocking)
     FD_ZERO(&rfds);
     FD_ZERO(&wfds);
     FD_ZERO(&xfds);
-    QLIST_FOREACH(ioh, &io_handlers, next) {
-        if (ioh->deleted)
-            continue;
-        if (ioh->fd_read &&
-            (!ioh->fd_read_poll ||
-             ioh->fd_read_poll(ioh->opaque) != 0)) {
-            FD_SET(ioh->fd, &rfds);
-            if (ioh->fd > nfds)
-                nfds = ioh->fd;
-        }
-        if (ioh->fd_write) {
-            FD_SET(ioh->fd, &wfds);
-            if (ioh->fd > nfds)
-                nfds = ioh->fd;
-        }
-    }
+    qemu_get_fdset(&nfds, &rfds, &wfds, &xfds);
 
     tv.tv_sec = timeout / 1000;
     tv.tv_usec = (timeout % 1000) * 1000;
@@ -1342,22 +1303,7 @@ void main_loop_wait(int nonblocking)
     ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv);
     qemu_mutex_lock_iothread();
     if (ret > 0) {
-        IOHandlerRecord *pioh;
-
-        QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {
-            if (!ioh->deleted && ioh->fd_read && FD_ISSET(ioh->fd, &rfds)) {
-                ioh->fd_read(ioh->opaque);
-            }
-            if (!ioh->deleted && ioh->fd_write && FD_ISSET(ioh->fd, &wfds)) {
-                ioh->fd_write(ioh->opaque);
-            }
-
-            /* Do this last in case read/write handlers marked it for deletion */
-            if (ioh->deleted) {
-                QLIST_REMOVE(ioh, next);
-                qemu_free(ioh);
-            }
-        }
+        qemu_process_fd_handlers(&rfds, &wfds, &xfds);
     }
 
     slirp_select_poll(&rfds, &wfds, &xfds, (ret < 0));
-- 
1.7.0.4