1 files changed, 0 insertions, 159 deletions
diff --git a/block/plug.c b/block/plug.c
deleted file mode 100644
index 98a155d2f4..0000000000
--- a/block/plug.c
+++ /dev/null
@@ -1,159 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * Block I/O plugging
- *
- * Copyright Red Hat.
- *
- * This API defers a function call within a blk_io_plug()/blk_io_unplug()
- * section, allowing multiple calls to batch up. This is a performance
- * optimization that is used in the block layer to submit several I/O requests
- * at once instead of individually:
- *
- *   blk_io_plug(); <-- start of plugged region
- *   ...
- *   blk_io_plug_call(my_func, my_obj); <-- deferred my_func(my_obj) call
- *   blk_io_plug_call(my_func, my_obj); <-- another
- *   blk_io_plug_call(my_func, my_obj); <-- another
- *   ...
- *   blk_io_unplug(); <-- end of plugged region, my_func(my_obj) is called once
- *
- * This code is actually generic and not tied to the block layer. If another
- * subsystem needs this functionality, it could be renamed.
- */
-
-#include "qemu/osdep.h"
-#include "qemu/coroutine-tls.h"
-#include "qemu/notify.h"
-#include "qemu/thread.h"
-#include "sysemu/block-backend.h"
-
-/* A function call that has been deferred until unplug() */
-typedef struct {
-    void (*fn)(void *);
-    void *opaque;
-} UnplugFn;
-
-/* Per-thread state */
-typedef struct {
-    unsigned count;       /* how many times has plug() been called? */
-    GArray *unplug_fns;   /* functions to call at unplug time */
-} Plug;
-
-/* Use get_ptr_plug() to fetch this thread-local value */
-QEMU_DEFINE_STATIC_CO_TLS(Plug, plug);
-
-/* Called at thread cleanup time */
-static void blk_io_plug_atexit(Notifier *n, void *value)
-{
-    Plug *plug = get_ptr_plug();
-    g_array_free(plug->unplug_fns, TRUE);
-}
-
-/* This won't involve coroutines, so use __thread */
-static __thread Notifier blk_io_plug_atexit_notifier;
-
-/**
- * blk_io_plug_call:
- * @fn: a function pointer to be invoked
- * @opaque: a user-defined argument to @fn()
- *
- * Call @fn(@opaque) immediately if not within a blk_io_plug()/blk_io_unplug()
- * section.
- *
- * Otherwise defer the call until the end of the outermost
- * blk_io_plug()/blk_io_unplug() section in this thread. If the same
- * @fn/@opaque pair has already been deferred, it will only be called once upon
- * blk_io_unplug() so that accumulated calls are batched into a single call.
- *
- * The caller must ensure that @opaque is not freed before @fn() is invoked.
- */
-void blk_io_plug_call(void (*fn)(void *), void *opaque)
-{
-    Plug *plug = get_ptr_plug();
-
-    /* Call immediately if we're not plugged */
-    if (plug->count == 0) {
-        fn(opaque);
-        return;
-    }
-
-    GArray *array = plug->unplug_fns;
-    if (!array) {
-        array = g_array_new(FALSE, FALSE, sizeof(UnplugFn));
-        plug->unplug_fns = array;
-        blk_io_plug_atexit_notifier.notify = blk_io_plug_atexit;
-        qemu_thread_atexit_add(&blk_io_plug_atexit_notifier);
-    }
-
-    UnplugFn *fns = (UnplugFn *)array->data;
-    UnplugFn new_fn = {
-        .fn = fn,
-        .opaque = opaque,
-    };
-
-    /*
-     * There won't be many, so do a linear search. If this becomes a bottleneck
-     * then a binary search (glib 2.62+) or different data structure could be
-     * used.
-     */
-    for (guint i = 0; i < array->len; i++) {
-        if (memcmp(&fns[i], &new_fn, sizeof(new_fn)) == 0) {
-            return; /* already exists */
-        }
-    }
-
-    g_array_append_val(array, new_fn);
-}
-
-/**
- * blk_io_plug: Defer blk_io_plug_call() functions until blk_io_unplug()
- *
- * blk_io_plug/unplug are thread-local operations. This means that multiple
- * threads can simultaneously call plug/unplug, but the caller must ensure that
- * each unplug() is called in the same thread of the matching plug().
- *
- * Nesting is supported. blk_io_plug_call() functions are only called at the
- * outermost blk_io_unplug().
- */
-void blk_io_plug(void)
-{
-    Plug *plug = get_ptr_plug();
-
-    assert(plug->count < UINT32_MAX);
-
-    plug->count++;
-}
-
-/**
- * blk_io_unplug: Run any pending blk_io_plug_call() functions
- *
- * There must have been a matching blk_io_plug() call in the same thread prior
- * to this blk_io_unplug() call.
- */
-void blk_io_unplug(void)
-{
-    Plug *plug = get_ptr_plug();
-
-    assert(plug->count > 0);
-
-    if (--plug->count > 0) {
-        return;
-    }
-
-    GArray *array = plug->unplug_fns;
-    if (!array) {
-        return;
-    }
-
-    UnplugFn *fns = (UnplugFn *)array->data;
-
-    for (guint i = 0; i < array->len; i++) {
-        fns[i].fn(fns[i].opaque);
-    }
-
-    /*
-     * This resets the array without freeing memory so that appending is cheap
-     * in the future.
-     */
-    g_array_set_size(array, 0);
-}