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ec150c7e09
Back in 2016, we discussed[1] rules for headers, and these were
generally liked:
1. Have a carefully curated header that's included everywhere first. We
got that already thanks to Peter: osdep.h.
2. Headers should normally include everything they need beyond osdep.h.
If exceptions are needed for some reason, they must be documented in
the header. If all that's needed from a header is typedefs, put
those into qemu/typedefs.h instead of including the header.
3. Cyclic inclusion is forbidden.
This patch gets include/ closer to obeying 2.
It's actually extracted from my "[RFC] Baby steps towards saner
headers" series[2], which demonstrates a possible path towards
checking 2 automatically. It passes the RFC test there.
[1] Message-ID: <87h9g8j57d.fsf@blackfin.pond.sub.org>
https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg03345.html
[2] Message-Id: <20190711122827.18970-1-armbru@redhat.com>
https://lists.nongnu.org/archive/html/qemu-devel/2019-07/msg02715.html
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20190812052359.30071-2-armbru@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
63 lines
1.6 KiB
C
63 lines
1.6 KiB
C
/*
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* QEMU System Emulator block write threshold notification
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*
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* Copyright Red Hat, Inc. 2014
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*
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* Authors:
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* Francesco Romani <fromani@redhat.com>
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*
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* This work is licensed under the terms of the GNU LGPL, version 2 or later.
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* See the COPYING.LIB file in the top-level directory.
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*/
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#ifndef BLOCK_WRITE_THRESHOLD_H
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#define BLOCK_WRITE_THRESHOLD_H
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#include "block/block_int.h"
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/*
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* bdrv_write_threshold_set:
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*
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* Set the write threshold for block devices, in bytes.
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* Notify when a write exceeds the threshold, meaning the device
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* is becoming full, so it can be transparently resized.
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* To be used with thin-provisioned block devices.
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*
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* Use threshold_bytes == 0 to disable.
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*/
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void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes);
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/*
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* bdrv_write_threshold_get
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*
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* Get the configured write threshold, in bytes.
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* Zero means no threshold configured.
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*/
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uint64_t bdrv_write_threshold_get(const BlockDriverState *bs);
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/*
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* bdrv_write_threshold_is_set
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*
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* Tell if a write threshold is set for a given BDS.
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*/
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bool bdrv_write_threshold_is_set(const BlockDriverState *bs);
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/*
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* bdrv_write_threshold_exceeded
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*
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* Return the extent of a write request that exceeded the threshold,
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* or zero if the request is below the threshold.
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* Return zero also if the threshold was not set.
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*
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* NOTE: here we assume the following holds for each request this code
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* deals with:
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*
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* assert((req->offset + req->bytes) <= UINT64_MAX)
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*
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* Please not there is *not* an actual C assert().
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*/
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uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs,
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const BdrvTrackedRequest *req);
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#endif
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