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1e361632da
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200319230737.GA16452@embeddedor.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
147 lines
4.1 KiB
C
147 lines
4.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
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*/
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#ifndef __LABEL_H__
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#define __LABEL_H__
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#include <linux/ndctl.h>
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#include <linux/sizes.h>
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#include <linux/uuid.h>
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#include <linux/io.h>
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enum {
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NSINDEX_SIG_LEN = 16,
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NSINDEX_ALIGN = 256,
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NSINDEX_SEQ_MASK = 0x3,
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NSLABEL_UUID_LEN = 16,
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NSLABEL_NAME_LEN = 64,
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NSLABEL_FLAG_ROLABEL = 0x1, /* read-only label */
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NSLABEL_FLAG_LOCAL = 0x2, /* DIMM-local namespace */
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NSLABEL_FLAG_BTT = 0x4, /* namespace contains a BTT */
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NSLABEL_FLAG_UPDATING = 0x8, /* label being updated */
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BTT_ALIGN = 4096, /* all btt structures */
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BTTINFO_SIG_LEN = 16,
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BTTINFO_UUID_LEN = 16,
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BTTINFO_FLAG_ERROR = 0x1, /* error state (read-only) */
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BTTINFO_MAJOR_VERSION = 1,
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ND_LABEL_MIN_SIZE = 256 * 4, /* see sizeof_namespace_index() */
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ND_LABEL_ID_SIZE = 50,
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ND_NSINDEX_INIT = 0x1,
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};
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/**
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* struct nd_namespace_index - label set superblock
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* @sig: NAMESPACE_INDEX\0
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* @flags: placeholder
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* @seq: sequence number for this index
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* @myoff: offset of this index in label area
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* @mysize: size of this index struct
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* @otheroff: offset of other index
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* @labeloff: offset of first label slot
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* @nslot: total number of label slots
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* @major: label area major version
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* @minor: label area minor version
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* @checksum: fletcher64 of all fields
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* @free[0]: bitmap, nlabel bits
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*
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* The size of free[] is rounded up so the total struct size is a
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* multiple of NSINDEX_ALIGN bytes. Any bits this allocates beyond
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* nlabel bits must be zero.
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*/
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struct nd_namespace_index {
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u8 sig[NSINDEX_SIG_LEN];
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u8 flags[3];
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u8 labelsize;
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__le32 seq;
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__le64 myoff;
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__le64 mysize;
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__le64 otheroff;
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__le64 labeloff;
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__le32 nslot;
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__le16 major;
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__le16 minor;
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__le64 checksum;
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u8 free[];
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};
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/**
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* struct nd_namespace_label - namespace superblock
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* @uuid: UUID per RFC 4122
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* @name: optional name (NULL-terminated)
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* @flags: see NSLABEL_FLAG_*
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* @nlabel: num labels to describe this ns
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* @position: labels position in set
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* @isetcookie: interleave set cookie
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* @lbasize: LBA size in bytes or 0 for pmem
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* @dpa: DPA of NVM range on this DIMM
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* @rawsize: size of namespace
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* @slot: slot of this label in label area
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* @unused: must be zero
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*/
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struct nd_namespace_label {
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u8 uuid[NSLABEL_UUID_LEN];
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u8 name[NSLABEL_NAME_LEN];
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__le32 flags;
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__le16 nlabel;
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__le16 position;
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__le64 isetcookie;
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__le64 lbasize;
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__le64 dpa;
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__le64 rawsize;
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__le32 slot;
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/*
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* Accessing fields past this point should be gated by a
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* namespace_label_has() check.
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*/
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u8 align;
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u8 reserved[3];
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guid_t type_guid;
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guid_t abstraction_guid;
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u8 reserved2[88];
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__le64 checksum;
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};
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#define NVDIMM_BTT_GUID "8aed63a2-29a2-4c66-8b12-f05d15d3922a"
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#define NVDIMM_BTT2_GUID "18633bfc-1735-4217-8ac9-17239282d3f8"
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#define NVDIMM_PFN_GUID "266400ba-fb9f-4677-bcb0-968f11d0d225"
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#define NVDIMM_DAX_GUID "97a86d9c-3cdd-4eda-986f-5068b4f80088"
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/**
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* struct nd_label_id - identifier string for dpa allocation
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* @id: "{blk|pmem}-<namespace uuid>"
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*/
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struct nd_label_id {
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char id[ND_LABEL_ID_SIZE];
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};
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/*
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* If the 'best' index is invalid, so is the 'next' index. Otherwise,
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* the next index is MOD(index+1, 2)
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*/
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static inline int nd_label_next_nsindex(int index)
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{
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if (index < 0)
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return -1;
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return (index + 1) % 2;
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}
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struct nvdimm_drvdata;
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int nd_label_data_init(struct nvdimm_drvdata *ndd);
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size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd);
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int nd_label_active_count(struct nvdimm_drvdata *ndd);
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struct nd_namespace_label *nd_label_active(struct nvdimm_drvdata *ndd, int n);
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u32 nd_label_alloc_slot(struct nvdimm_drvdata *ndd);
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bool nd_label_free_slot(struct nvdimm_drvdata *ndd, u32 slot);
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u32 nd_label_nfree(struct nvdimm_drvdata *ndd);
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enum nvdimm_claim_class to_nvdimm_cclass(guid_t *guid);
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struct nd_region;
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struct nd_namespace_pmem;
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struct nd_namespace_blk;
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int nd_pmem_namespace_label_update(struct nd_region *nd_region,
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struct nd_namespace_pmem *nspm, resource_size_t size);
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int nd_blk_namespace_label_update(struct nd_region *nd_region,
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struct nd_namespace_blk *nsblk, resource_size_t size);
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#endif /* __LABEL_H__ */
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