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Tsirkin" Cc: Sam Li , Damien Le Moal , Niklas Cassel , qemu-block@nongnu.org, qemu-devel@nongnu.org Subject: [PATCH v4 03/12] block: add a helper for the index of the zone an offset falls in Date: Mon, 7 Sep 2026 13:07:38 +0200 Message-ID: <20260907110748.1868714-4-cassel@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260907110748.1868714-1-cassel@kernel.org> References: <20260907110748.1868714-1-cassel@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=172.234.252.31; envelope-from=cassel@kernel.org; helo=sea.source.kernel.org X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Deriving the zone that an offset belongs to is open coded in five places, in two files, as a division of the offset by BlockLimits.zone_size. The zone size of a zoned device is always a power of two. Linux requires that of every zoned device it accepts, in blk_revalidate_disk_zones() and in each of the drivers that report one, and qcow2 rejects an image whose header says otherwise. So the division is a shift, and the shift is worth deriving once rather than at every use: record it in BlockLimits as zone_size_bits, next to the size it comes from, and assert the property that it relies on where it is computed. Add bdrv_zone_index() and use it. No functional change; the count of zones that a management operation spans stays a division, since it is a length rather than an offset. Reviewed-by: Damien Le Moal Signed-off-by: Niklas Cassel --- block/file-posix.c | 8 ++++---- block/io.c | 12 ++++++++++++ hw/block/virtio-blk.c | 2 +- include/block/block-io.h | 2 ++ include/block/block_int-common.h | 7 +++++++ 5 files changed, 26 insertions(+), 5 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index c0d6ee30e4..00323f7a9f 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1359,7 +1359,7 @@ static int get_zones_wp(BlockDriverState *bs, int fd, int64_t offset, size_t rep_size; uint64_t sector = offset >> BDRV_SECTOR_BITS; BlockZoneWps *wps = bs->wps; - unsigned int j = offset / bs->bl.zone_size; + unsigned int j = bdrv_zone_index(bs, offset); unsigned int n = 0, i = 0; int ret; rep_size = sizeof(struct blk_zone_report) + nrz * sizeof(struct blk_zone); @@ -2560,7 +2560,7 @@ raw_co_prw(BlockDriverState *bs, int64_t *offset_ptr, uint64_t bytes, bs->bl.zoned != BLK_Z_NONE) { qemu_co_mutex_lock(&bs->wps->colock); if (type & QEMU_AIO_ZONE_APPEND) { - int index = offset / bs->bl.zone_size; + int index = bdrv_zone_index(bs, offset); offset = bs->wps->wp[index]; } } @@ -2615,7 +2615,7 @@ out: bs->bl.zoned != BLK_Z_NONE) { BlockZoneWps *wps = bs->wps; if (ret == 0) { - uint64_t *wp = &wps->wp[offset / bs->bl.zone_size]; + uint64_t *wp = &wps->wp[bdrv_zone_index(bs, offset)]; if (!BDRV_ZT_IS_CONV(*wp)) { if (type & QEMU_AIO_ZONE_APPEND) { *offset_ptr = *wp; @@ -3513,7 +3513,7 @@ static int coroutine_fn raw_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp op, return -EINVAL; } - uint32_t i = offset / bs->bl.zone_size; + uint32_t i = bdrv_zone_index(bs, offset); uint32_t nrz = len / bs->bl.zone_size; uint64_t *wp = &wps->wp[i]; if (BDRV_ZT_IS_CONV(*wp) && len != capacity) { diff --git a/block/io.c b/block/io.c index a916b236c3..cef23ee5bc 100644 --- a/block/io.c +++ b/block/io.c @@ -227,6 +227,11 @@ void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp) } } + if (bs->bl.zone_size) { + assert(is_power_of_2(bs->bl.zone_size)); + bs->bl.zone_size_bits = ctz64(bs->bl.zone_size); + } + if (bs->bl.request_alignment > BDRV_MAX_ALIGNMENT) { error_setg(errp, "Driver requires too large request alignment"); } @@ -3361,6 +3366,13 @@ out: return co.ret; } +uint32_t bdrv_zone_index(BlockDriverState *bs, uint64_t offset) +{ + IO_CODE(); + + return offset >> bs->bl.zone_size_bits; +} + void *qemu_blockalign(BlockDriverState *bs, size_t size) { IO_CODE(); diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index ffcd327803..8c5b87793e 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -527,7 +527,7 @@ static bool check_zoned_request(VirtIOBlock *s, int64_t offset, int64_t len, } } - index = offset / bs->bl.zone_size; + index = bdrv_zone_index(bs, offset); if (BDRV_ZT_IS_CONV(bs->wps->wp[index])) { *status = VIRTIO_BLK_S_ZONE_INVALID_CMD; return false; diff --git a/include/block/block-io.h b/include/block/block-io.h index d34d846bb2..9d1c0eb7fb 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -126,6 +126,8 @@ int coroutine_fn GRAPH_RDLOCK bdrv_co_zone_append(BlockDriverState *bs, int64_t *offset, QEMUIOVector *qiov, BdrvRequestFlags flags); +/* The index of the zone that @offset falls in. */ +uint32_t bdrv_zone_index(BlockDriverState *bs, uint64_t offset); bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs); diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index 7571ed9968..82aa0c1a6e 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -903,6 +903,13 @@ typedef struct BlockLimits { /* zone size expressed in bytes */ uint64_t zone_size; + /* + * log2 of zone_size, derived by bdrv_refresh_limits(). A zoned device + * always has a zone size that is a power of two, so the zone an offset + * falls in is a shift rather than a division. See bdrv_zone_index(). + */ + uint32_t zone_size_bits; + /* total number of zones */ uint32_t nr_zones; -- 2.55.0