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277fc1ce18
Make BlockExportType.iothread an alternate between a single-thread variant 'str' and a multi-threading variant '[str]'. In contrast to the single-thread setting, the multi-threading setting will not change the BDS's context (and so is incompatible with the fixed-iothread setting), but instead just pass a list to the export driver, with which it can do whatever it wants. Currently no export driver supports multi-threading, so they all return an error when receiving such a list. Suggested-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Hanna Czenczek <hreitz@redhat.com> Message-ID: <20260309150856.26800-21-hreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
103 lines
2.9 KiB
C
103 lines
2.9 KiB
C
/*
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* Declarations for block exports
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*
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* Copyright (c) 2012, 2020 Red Hat, Inc.
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*
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* Authors:
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* Paolo Bonzini <pbonzini@redhat.com>
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* Kevin Wolf <kwolf@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or
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* later. See the COPYING file in the top-level directory.
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*/
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#ifndef BLOCK_EXPORT_H
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#define BLOCK_EXPORT_H
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#include "qapi/qapi-types-block-export.h"
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#include "qemu/queue.h"
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typedef struct BlockExport BlockExport;
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typedef struct BlockExportDriver {
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/* The export type that this driver services */
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BlockExportType type;
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/*
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* The size of the driver-specific state that contains BlockExport as its
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* first field.
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*/
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size_t instance_size;
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/* True if the export type supports running on an inactive node */
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bool supports_inactive;
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/*
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* Creates and starts a new block export.
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*
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* If the user passed a set of I/O threads for multi-threading, @multithread
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* is a list of the @multithread_count corresponding contexts (freed by the
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* caller). Note that @exp->ctx has no relation to that list.
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*/
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int (*create)(BlockExport *exp, BlockExportOptions *opts,
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AioContext *const *multithread, size_t multithread_count,
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Error **errp);
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/*
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* Frees a removed block export. This function is only called after all
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* references have been dropped.
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*/
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void (*delete)(BlockExport *);
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/*
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* Start to disconnect all clients and drop other references held
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* internally by the export driver. When the function returns, there may
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* still be active references while the export is in the process of
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* shutting down.
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*/
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void (*request_shutdown)(BlockExport *);
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} BlockExportDriver;
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struct BlockExport {
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const BlockExportDriver *drv;
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/* Unique identifier for the export */
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char *id;
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/*
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* Reference count for this block export. This includes strong references
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* both from the owner (qemu-nbd or the monitor) and clients connected to
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* the export.
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*
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* Use atomics to access this field.
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*/
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int refcount;
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/*
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* True if one of the references in refcount belongs to the user. After the
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* user has dropped their reference, they may not e.g. remove the same
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* export a second time (which would decrease the refcount without having
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* it incremented first).
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*/
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bool user_owned;
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/* The AioContext whose lock protects this BlockExport object. */
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AioContext *ctx;
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/* The block device to export */
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BlockBackend *blk;
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/* List entry for block_exports */
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QLIST_ENTRY(BlockExport) next;
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};
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BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp);
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BlockExport *blk_exp_find(const char *id);
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void blk_exp_ref(BlockExport *exp);
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void blk_exp_unref(BlockExport *exp);
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void blk_exp_request_shutdown(BlockExport *exp);
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void blk_exp_close_all(void);
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void blk_exp_close_all_type(BlockExportType type);
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#endif
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