include/sysemu/block-backend: split header into I/O and global state …

…(GS) API

Similarly to the previous patches, split block-backend.h
in block-backend-io.h and block-backend-global-state.h

In addition, remove "block/block.h" include as it seems
it is not necessary anymore, together with "qemu/iov.h"

block-backend-common.h contains the structures shared between
the two headers, and the functions that can't be categorized as
I/O or global state.

Assertions are added in the next patch.

Signed-off-by: Emanuele Giuseppe Esposito <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>

block/block-backend.c

@@ -79,6 +79,7 @@ struct BlockBackend {
     bool allow_aio_context_change;
     bool allow_write_beyond_eof;
 
+    /* Protected by BQL */
     NotifierList remove_bs_notifiers, insert_bs_notifiers;
     QLIST_HEAD(, BlockBackendAioNotifier) aio_notifiers;
 
@@ -111,12 +112,14 @@ static const AIOCBInfo block_backend_aiocb_info = {
 static void drive_info_del(DriveInfo *dinfo);
 static BlockBackend *bdrv_first_blk(BlockDriverState *bs);
 
-/* All BlockBackends */
+/* All BlockBackends. Protected by BQL. */
 static QTAILQ_HEAD(, BlockBackend) block_backends =
     QTAILQ_HEAD_INITIALIZER(block_backends);
 
-/* All BlockBackends referenced by the monitor and which are iterated through by
- * blk_next() */
+/*
+ * All BlockBackends referenced by the monitor and which are iterated through by
+ * blk_next(). Protected by BQL.
+ */
 static QTAILQ_HEAD(, BlockBackend) monitor_block_backends =
     QTAILQ_HEAD_INITIALIZER(monitor_block_backends);
 

include/sysemu/block-backend-common.h

@@ -0,0 +1,84 @@
+/*
+ * QEMU Block backends
+ *
+ * Copyright (C) 2014-2016 Red Hat, Inc.
+ *
+ * Authors:
+ *  Markus Armbruster <[email protected]>,
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1
+ * or later.  See the COPYING.LIB file in the top-level directory.
+ */
+
+#ifndef BLOCK_BACKEND_COMMON_H
+#define BLOCK_BACKEND_COMMON_H
+
+#include "qemu/iov.h"
+#include "block/throttle-groups.h"
+
+/*
+ * TODO Have to include block/block.h for a bunch of block layer
+ * types.  Unfortunately, this pulls in the whole BlockDriverState
+ * API, which we don't want used by many BlockBackend users.  Some of
+ * the types belong here, and the rest should be split into a common
+ * header and one for the BlockDriverState API.
+ */
+#include "block/block.h"
+
+/* Callbacks for block device models */
+typedef struct BlockDevOps {
+    /*
+     * Runs when virtual media changed (monitor commands eject, change)
+     * Argument load is true on load and false on eject.
+     * Beware: doesn't run when a host device's physical media
+     * changes.  Sure would be useful if it did.
+     * Device models with removable media must implement this callback.
+     */
+    void (*change_media_cb)(void *opaque, bool load, Error **errp);
+    /*
+     * Runs when an eject request is issued from the monitor, the tray
+     * is closed, and the medium is locked.
+     * Device models that do not implement is_medium_locked will not need
+     * this callback.  Device models that can lock the medium or tray might
+     * want to implement the callback and unlock the tray when "force" is
+     * true, even if they do not support eject requests.
+     */
+    void (*eject_request_cb)(void *opaque, bool force);
+    /*
+     * Is the virtual tray open?
+     * Device models implement this only when the device has a tray.
+     */
+    bool (*is_tray_open)(void *opaque);
+    /*
+     * Is the virtual medium locked into the device?
+     * Device models implement this only when device has such a lock.
+     */
+    bool (*is_medium_locked)(void *opaque);
+    /*
+     * Runs when the size changed (e.g. monitor command block_resize)
+     */
+    void (*resize_cb)(void *opaque);
+    /*
+     * Runs when the backend receives a drain request.
+     */
+    void (*drained_begin)(void *opaque);
+    /*
+     * Runs when the backend's last drain request ends.
+     */
+    void (*drained_end)(void *opaque);
+    /*
+     * Is the device still busy?
+     */
+    bool (*drained_poll)(void *opaque);
+} BlockDevOps;
+
+/*
+ * This struct is embedded in (the private) BlockBackend struct and contains
+ * fields that must be public. This is in particular for QLIST_ENTRY() and
+ * friends so that BlockBackends can be kept in lists outside block-backend.c
+ */
+typedef struct BlockBackendPublic {
+    ThrottleGroupMember throttle_group_member;
+} BlockBackendPublic;
+
+#endif /* BLOCK_BACKEND_COMMON_H */

include/sysemu/block-backend-global-state.h

@@ -0,0 +1,116 @@
+/*
+ * QEMU Block backends
+ *
+ * Copyright (C) 2014-2016 Red Hat, Inc.
+ *
+ * Authors:
+ *  Markus Armbruster <[email protected]>,
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1
+ * or later.  See the COPYING.LIB file in the top-level directory.
+ */
+
+#ifndef BLOCK_BACKEND_GS_H
+#define BLOCK_BACKEND_GS_H
+
+#include "block-backend-common.h"
+
+/*
+ * Global state (GS) API. These functions run under the BQL.
+ *
+ * See include/block/block-global-state.h for more information about
+ * the GS API.
+ */
+
+BlockBackend *blk_new(AioContext *ctx, uint64_t perm, uint64_t shared_perm);
+BlockBackend *blk_new_with_bs(BlockDriverState *bs, uint64_t perm,
+                              uint64_t shared_perm, Error **errp);
+BlockBackend *blk_new_open(const char *filename, const char *reference,
+                           QDict *options, int flags, Error **errp);
+int blk_get_refcnt(BlockBackend *blk);
+void blk_ref(BlockBackend *blk);
+void blk_unref(BlockBackend *blk);
+void blk_remove_all_bs(void);
+BlockBackend *blk_by_name(const char *name);
+BlockBackend *blk_next(BlockBackend *blk);
+BlockBackend *blk_all_next(BlockBackend *blk);
+bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp);
+void monitor_remove_blk(BlockBackend *blk);
+
+BlockBackendPublic *blk_get_public(BlockBackend *blk);
+BlockBackend *blk_by_public(BlockBackendPublic *public);
+
+void blk_remove_bs(BlockBackend *blk);
+int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp);
+int blk_replace_bs(BlockBackend *blk, BlockDriverState *new_bs, Error **errp);
+bool bdrv_has_blk(BlockDriverState *bs);
+bool bdrv_is_root_node(BlockDriverState *bs);
+int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
+                 Error **errp);
+void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm);
+
+void blk_iostatus_enable(BlockBackend *blk);
+BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk);
+void blk_iostatus_disable(BlockBackend *blk);
+void blk_iostatus_reset(BlockBackend *blk);
+int blk_attach_dev(BlockBackend *blk, DeviceState *dev);
+void blk_detach_dev(BlockBackend *blk, DeviceState *dev);
+DeviceState *blk_get_attached_dev(BlockBackend *blk);
+BlockBackend *blk_by_dev(void *dev);
+BlockBackend *blk_by_qdev_id(const char *id, Error **errp);
+void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque);
+
+void blk_activate(BlockBackend *blk, Error **errp);
+
+int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags);
+void blk_aio_cancel(BlockAIOCB *acb);
+int blk_commit_all(void);
+void blk_drain(BlockBackend *blk);
+void blk_drain_all(void);
+void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error,
+                      BlockdevOnError on_write_error);
+bool blk_supports_write_perm(BlockBackend *blk);
+bool blk_is_sg(BlockBackend *blk);
+void blk_set_enable_write_cache(BlockBackend *blk, bool wce);
+int blk_get_flags(BlockBackend *blk);
+bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp);
+void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason);
+void blk_op_block_all(BlockBackend *blk, Error *reason);
+void blk_op_unblock_all(BlockBackend *blk, Error *reason);
+int blk_set_aio_context(BlockBackend *blk, AioContext *new_context,
+                        Error **errp);
+void blk_add_aio_context_notifier(BlockBackend *blk,
+        void (*attached_aio_context)(AioContext *new_context, void *opaque),
+        void (*detach_aio_context)(void *opaque), void *opaque);
+void blk_remove_aio_context_notifier(BlockBackend *blk,
+                                     void (*attached_aio_context)(AioContext *,
+                                                                  void *),
+                                     void (*detach_aio_context)(void *),
+                                     void *opaque);
+void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify);
+void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify);
+BlockBackendRootState *blk_get_root_state(BlockBackend *blk);
+void blk_update_root_state(BlockBackend *blk);
+bool blk_get_detect_zeroes_from_root_state(BlockBackend *blk);
+int blk_get_open_flags_from_root_state(BlockBackend *blk);
+
+int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
+                     int64_t pos, int size);
+int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size);
+int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz);
+int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo);
+
+void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg);
+void blk_io_limits_disable(BlockBackend *blk);
+void blk_io_limits_enable(BlockBackend *blk, const char *group);
+void blk_io_limits_update_group(BlockBackend *blk, const char *group);
+void blk_set_force_allow_inactivate(BlockBackend *blk);
+
+void blk_register_buf(BlockBackend *blk, void *host, size_t size);
+void blk_unregister_buf(BlockBackend *blk, void *host);
+
+const BdrvChild *blk_root(BlockBackend *blk);
+
+int blk_make_empty(BlockBackend *blk, Error **errp);
+
+#endif /* BLOCK_BACKEND_GS_H */

include/sysemu/block-backend-io.h

@@ -0,0 +1,159 @@
+/*
+ * QEMU Block backends
+ *
+ * Copyright (C) 2014-2016 Red Hat, Inc.
+ *
+ * Authors:
+ *  Markus Armbruster <[email protected]>,
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1
+ * or later.  See the COPYING.LIB file in the top-level directory.
+ */
+
+#ifndef BLOCK_BACKEND_IO_H
+#define BLOCK_BACKEND_IO_H
+
+#include "block-backend-common.h"
+
+/*
+ * I/O API functions. These functions are thread-safe.
+ *
+ * See include/block/block-io.h for more information about
+ * the I/O API.
+ */
+
+const char *blk_name(const BlockBackend *blk);
+
+BlockDriverState *blk_bs(BlockBackend *blk);
+
+void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow);
+void blk_set_allow_aio_context_change(BlockBackend *blk, bool allow);
+void blk_set_disable_request_queuing(BlockBackend *blk, bool disable);
+bool blk_iostatus_is_enabled(const BlockBackend *blk);
+
+char *blk_get_attached_dev_id(BlockBackend *blk);
+
+BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
+                                  int64_t bytes, BdrvRequestFlags flags,
+                                  BlockCompletionFunc *cb, void *opaque);
+
+BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset,
+                           QEMUIOVector *qiov, BdrvRequestFlags flags,
+                           BlockCompletionFunc *cb, void *opaque);
+BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
+                            QEMUIOVector *qiov, BdrvRequestFlags flags,
+                            BlockCompletionFunc *cb, void *opaque);
+BlockAIOCB *blk_aio_flush(BlockBackend *blk,
+                          BlockCompletionFunc *cb, void *opaque);
+BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes,
+                             BlockCompletionFunc *cb, void *opaque);
+void blk_aio_cancel_async(BlockAIOCB *acb);
+BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
+                          BlockCompletionFunc *cb, void *opaque);
+
+void blk_inc_in_flight(BlockBackend *blk);
+void blk_dec_in_flight(BlockBackend *blk);
+bool blk_is_inserted(BlockBackend *blk);
+bool blk_is_available(BlockBackend *blk);
+void blk_lock_medium(BlockBackend *blk, bool locked);
+void blk_eject(BlockBackend *blk, bool eject_flag);
+int64_t blk_getlength(BlockBackend *blk);
+void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr);
+int64_t blk_nb_sectors(BlockBackend *blk);
+void *blk_try_blockalign(BlockBackend *blk, size_t size);
+void *blk_blockalign(BlockBackend *blk, size_t size);
+bool blk_is_writable(BlockBackend *blk);
+bool blk_enable_write_cache(BlockBackend *blk);
+BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read);
+BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read,
+                                      int error);
+void blk_error_action(BlockBackend *blk, BlockErrorAction action,
+                      bool is_read, int error);
+void blk_iostatus_set_err(BlockBackend *blk, int error);
+int blk_get_max_iov(BlockBackend *blk);
+int blk_get_max_hw_iov(BlockBackend *blk);
+void blk_set_guest_block_size(BlockBackend *blk, int align);
+
+void blk_io_plug(BlockBackend *blk);
+void blk_io_unplug(BlockBackend *blk);
+AioContext *blk_get_aio_context(BlockBackend *blk);
+BlockAcctStats *blk_get_stats(BlockBackend *blk);
+void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
+                  BlockCompletionFunc *cb, void *opaque);
+BlockAIOCB *blk_abort_aio_request(BlockBackend *blk,
+                                  BlockCompletionFunc *cb,
+                                  void *opaque, int ret);
+
+uint32_t blk_get_request_alignment(BlockBackend *blk);
+uint32_t blk_get_max_transfer(BlockBackend *blk);
+uint64_t blk_get_max_hw_transfer(BlockBackend *blk);
+
+int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
+                                   BlockBackend *blk_out, int64_t off_out,
+                                   int64_t bytes, BdrvRequestFlags read_flags,
+                                   BdrvRequestFlags write_flags);
+
+
+/*
+ * "I/O or GS" API functions. These functions can run without
+ * the BQL, but only in one specific iothread/main loop.
+ *
+ * See include/block/block-io.h for more information about
+ * the "I/O or GS" API.
+ */
+
+int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int bytes);
+int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int bytes,
+               BdrvRequestFlags flags);
+int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
+                               int64_t bytes, QEMUIOVector *qiov,
+                               BdrvRequestFlags flags);
+int coroutine_fn blk_co_pwritev_part(BlockBackend *blk, int64_t offset,
+                                     int64_t bytes,
+                                     QEMUIOVector *qiov, size_t qiov_offset,
+                                     BdrvRequestFlags flags);
+int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
+                                int64_t bytes, QEMUIOVector *qiov,
+                                BdrvRequestFlags flags);
+
+static inline int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset,
+                                            int64_t bytes, void *buf,
+                                            BdrvRequestFlags flags)
+{
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
+
+    assert(bytes <= SIZE_MAX);
+
+    return blk_co_preadv(blk, offset, bytes, &qiov, flags);
+}
+
+static inline int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset,
+                                             int64_t bytes, void *buf,
+                                             BdrvRequestFlags flags)
+{
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
+
+    assert(bytes <= SIZE_MAX);
+
+    return blk_co_pwritev(blk, offset, bytes, &qiov, flags);
+}
+
+int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset,
+                                 int64_t bytes);
+
+int coroutine_fn blk_co_flush(BlockBackend *blk);
+int blk_flush(BlockBackend *blk);
+
+int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
+
+int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
+                          int64_t bytes);
+int blk_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes);
+int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
+                      int64_t bytes, BdrvRequestFlags flags);
+int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
+                                      int64_t bytes, BdrvRequestFlags flags);
+int blk_truncate(BlockBackend *blk, int64_t offset, bool exact,
+                 PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
+
+#endif /* BLOCK_BACKEND_IO_H */