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[81.40.121.121]) by smtp.gmail.com with ESMTPSA id j4sm7191494wmi.48.2020.08.21.12.54.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Aug 2020 12:54:43 -0700 (PDT) From: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Subject: [PATCH v6 08/15] block/nvme: Use union of NvmeIdCtrl / NvmeIdNs structures Date: Fri, 21 Aug 2020 21:53:52 +0200 Message-Id: <20200821195359.1285345-9-philmd@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200821195359.1285345-1-philmd@redhat.com> References: <20200821195359.1285345-1-philmd@redhat.com> MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=philmd@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.81; envelope-from=philmd@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/21 05:15:56 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Max Reitz , Stefan Hajnoczi , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Stefano Garzarella Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We allocate an unique chunk of memory then use it for two different structures. By using an union, we make it clear the data is overlapping (and we can remove the casts). Suggested-by: Stefan Hajnoczi Reviewed-by: Stefan Hajnoczi Reviewed-by: Stefano Garzarella Signed-off-by: Philippe Mathieu-Daudé --- block/nvme.c | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-) diff --git a/block/nvme.c b/block/nvme.c index 15c5202c03c..af3176a9669 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -508,9 +508,10 @@ static int nvme_cmd_sync(BlockDriverState *bs, NVMeQueuePair *q, static void nvme_identify(BlockDriverState *bs, int namespace, Error **errp) { BDRVNVMeState *s = bs->opaque; - NvmeIdCtrl *idctrl; - NvmeIdNs *idns; - uint8_t *id; + union { + NvmeIdCtrl ctrl; + NvmeIdNs ns; + } *id; NvmeLBAF *lbaf; uint16_t oncs; int r; @@ -520,14 +521,12 @@ static void nvme_identify(BlockDriverState *bs, int namespace, Error **errp) .cdw10 = cpu_to_le32(0x1), }; - id = qemu_try_blockalign0(bs, sizeof(NvmeIdCtrl)); + id = qemu_try_blockalign0(bs, sizeof(*id)); if (!id) { error_setg(errp, "Cannot allocate buffer for identify response"); goto out; } - idctrl = (NvmeIdCtrl *)id; - idns = (NvmeIdNs *)id; - r = qemu_vfio_dma_map(s->vfio, id, sizeof(NvmeIdCtrl), true, &iova); + r = qemu_vfio_dma_map(s->vfio, id, sizeof(*id), true, &iova); if (r) { error_setg(errp, "Cannot map buffer for DMA"); goto out; @@ -539,22 +538,22 @@ static void nvme_identify(BlockDriverState *bs, int namespace, Error **errp) goto out; } - if (le32_to_cpu(idctrl->nn) < namespace) { + if (le32_to_cpu(id->ctrl.nn) < namespace) { error_setg(errp, "Invalid namespace"); goto out; } - s->write_cache_supported = le32_to_cpu(idctrl->vwc) & 0x1; - s->max_transfer = (idctrl->mdts ? 1 << idctrl->mdts : 0) * s->page_size; + s->write_cache_supported = le32_to_cpu(id->ctrl.vwc) & 0x1; + s->max_transfer = (id->ctrl.mdts ? 1 << id->ctrl.mdts : 0) * s->page_size; /* For now the page list buffer per command is one page, to hold at most * s->page_size / sizeof(uint64_t) entries. */ s->max_transfer = MIN_NON_ZERO(s->max_transfer, s->page_size / sizeof(uint64_t) * s->page_size); - oncs = le16_to_cpu(idctrl->oncs); + oncs = le16_to_cpu(id->ctrl.oncs); s->supports_write_zeroes = !!(oncs & NVME_ONCS_WRITE_ZEROS); s->supports_discard = !!(oncs & NVME_ONCS_DSM); - memset(id, 0, 4096); + memset(id, 0, sizeof(*id)); cmd.cdw10 = 0; cmd.nsid = cpu_to_le32(namespace); if (nvme_cmd_sync(bs, s->queues[INDEX_ADMIN], &cmd)) { @@ -562,11 +561,11 @@ static void nvme_identify(BlockDriverState *bs, int namespace, Error **errp) goto out; } - s->nsze = le64_to_cpu(idns->nsze); - lbaf = &idns->lbaf[NVME_ID_NS_FLBAS_INDEX(idns->flbas)]; + s->nsze = le64_to_cpu(id->ns.nsze); + lbaf = &id->ns.lbaf[NVME_ID_NS_FLBAS_INDEX(id->ns.flbas)]; - if (NVME_ID_NS_DLFEAT_WRITE_ZEROES(idns->dlfeat) && - NVME_ID_NS_DLFEAT_READ_BEHAVIOR(idns->dlfeat) == + if (NVME_ID_NS_DLFEAT_WRITE_ZEROES(id->ns.dlfeat) && + NVME_ID_NS_DLFEAT_READ_BEHAVIOR(id->ns.dlfeat) == NVME_ID_NS_DLFEAT_READ_BEHAVIOR_ZEROES) { bs->supported_write_flags |= BDRV_REQ_MAY_UNMAP; }