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block/nvme: Use union of NvmeIdCtrl / NvmeIdNs structures

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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 <stefanha@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200821195359.1285345-9-philmd@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Philippe Mathieu-Daudé 2020-08-21 21:53:52 +02:00 • committed by Kevin Wolf
parent 4d98093937
commit 7d3b214ae4
1 changed files with 15 additions and 16 deletions
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31
block/nvme.c
View file

@ -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_ZEROES);
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;
}