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[PATCH v2 06/12] block/nvme: Use union of NvmeIdCtrl / NvmeIdNs structur
From: |
Philippe Mathieu-Daudé |
Subject: |
[PATCH v2 06/12] block/nvme: Use union of NvmeIdCtrl / NvmeIdNs structures |
Date: |
Tue, 30 Jun 2020 21:13:12 +0200 |
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>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
block/nvme.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)
diff --git a/block/nvme.c b/block/nvme.c
index b9760ff04f..7ebd5be1f3 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[QUEUE_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;
}
--
2.21.3
- [PATCH v2 00/12] block/nvme: Various cleanups required to use multiple queues, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 01/12] block/nvme: Replace magic value by SCALE_MS definition, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 02/12] block/nvme: Avoid further processing if trace event not enabled, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 03/12] block/nvme: Let nvme_create_queue_pair() fail gracefully, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 04/12] block/nvme: Define QUEUE_INDEX macros to ease code review, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 05/12] block/nvme: Rename local variable, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 09/12] block/nvme: Simplify nvme_init_queue() arguments, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 10/12] block/nvme: Replace BDRV_POLL_WHILE by AIO_WAIT_WHILE, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 08/12] block/nvme: Replace qemu_try_blockalign(bs) by qemu_try_memalign(pg_sz), Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 11/12] block/nvme: Simplify nvme_create_queue_pair() arguments, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 06/12] block/nvme: Use union of NvmeIdCtrl / NvmeIdNs structures,
Philippe Mathieu-Daudé <=
- [PATCH v2 12/12] block/nvme: Use per-queue AIO context, Philippe Mathieu-Daudé, 2020/06/30
- [PATCH v2 07/12] block/nvme: Replace qemu_try_blockalign0 by qemu_try_blockalign/memset, Philippe Mathieu-Daudé, 2020/06/30