Merge tag 'flex-array-conversions-5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull flexible-array member conversions from Gustavo A. R. Silva:
 "Replace zero-length arrays with flexible-array members.

  Notice that all of these patches have been baking in linux-next for
  two development cycles now.

  There is a regular need in the kernel to provide a way to declare
  having a dynamically sized set of trailing elements in a structure.
  Kernel code should always use “flexible array members”[1] for these
  cases. The older style of one-element or zero-length arrays should no
  longer be used[2].

  C99 introduced “flexible array members”, which lacks a numeric size
  for the array declaration entirely:

        struct something {
                size_t count;
                struct foo items[];
        };

  This is the way the kernel expects dynamically sized trailing elements
  to be declared. It allows the compiler to generate errors when the
  flexible array does not occur last in the structure, which helps to
  prevent some kind of undefined behavior[3] bugs from being
  inadvertently introduced to the codebase.

  It also allows the compiler to correctly analyze array sizes (via
  sizeof(), CONFIG_FORTIFY_SOURCE, and CONFIG_UBSAN_BOUNDS). For
  instance, there is no mechanism that warns us that the following
  application of the sizeof() operator to a zero-length array always
  results in zero:

        struct something {
                size_t count;
                struct foo items[0];
        };

        struct something *instance;

        instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
        instance->count = count;

        size = sizeof(instance->items) * instance->count;
        memcpy(instance->items, source, size);

  At the last line of code above, size turns out to be zero, when one
  might have thought it represents the total size in bytes of the
  dynamic memory recently allocated for the trailing array items. Here
  are a couple examples of this issue[4][5].

  Instead, flexible array members have incomplete type, and so the
  sizeof() operator may not be applied[6], so any misuse of such
  operators will be immediately noticed at build time.

  The cleanest and least error-prone way to implement this is through
  the use of a flexible array member:

        struct something {
                size_t count;
                struct foo items[];
        };

        struct something *instance;

        instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
        instance->count = count;

        size = sizeof(instance->items[0]) * instance->count;
        memcpy(instance->items, source, size);

  instead"

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
[4] commit f2cd32a443da ("rndis_wlan: Remove logically dead code")
[5] commit ab91c2a89f86 ("tpm: eventlog: Replace zero-length array with flexible-array member")
[6] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html

* tag 'flex-array-conversions-5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux: (41 commits)
  w1: Replace zero-length array with flexible-array
  tracing/probe: Replace zero-length array with flexible-array
  soc: ti: Replace zero-length array with flexible-array
  tifm: Replace zero-length array with flexible-array
  dmaengine: tegra-apb: Replace zero-length array with flexible-array
  stm class: Replace zero-length array with flexible-array
  Squashfs: Replace zero-length array with flexible-array
  ASoC: SOF: Replace zero-length array with flexible-array
  ima: Replace zero-length array with flexible-array
  sctp: Replace zero-length array with flexible-array
  phy: samsung: Replace zero-length array with flexible-array
  RxRPC: Replace zero-length array with flexible-array
  rapidio: Replace zero-length array with flexible-array
  media: pwc: Replace zero-length array with flexible-array
  firmware: pcdp: Replace zero-length array with flexible-array
  oprofile: Replace zero-length array with flexible-array
  block: Replace zero-length array with flexible-array
  tools/testing/nvdimm: Replace zero-length array with flexible-array
  libata: Replace zero-length array with flexible-array
  kprobes: Replace zero-length array with flexible-array
  ...

10 files changed, 28 insertions, 28 deletions

diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h
index a954def26c0d..900b9f4e0605 100644
--- a/include/linux/can/skb.h
+++ b/include/linux/can/skb.h
@@ -34,7 +34,7 @@
 struct can_skb_priv {
 	int ifindex;
 	int skbcnt;
-	struct can_frame cf[0];
+	struct can_frame cf[];
 };
 
 static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb)
diff --git a/include/linux/cb710.h b/include/linux/cb710.h
index 60de3fedd3a7..405657a9a0d5 100644
--- a/include/linux/cb710.h
+++ b/include/linux/cb710.h
@@ -36,7 +36,7 @@ struct cb710_chip {
 	unsigned		slot_mask;
 	unsigned		slots;
 	spinlock_t		irq_lock;
-	struct cb710_slot	slot[0];
+	struct cb710_slot	slot[];
 };
 
 /* NOTE: cb710_chip.slots is modified only during device init/exit and
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index e1c03339918f..6283917edd90 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -153,7 +153,7 @@ struct dma_interleaved_template {
 	bool dst_sgl;
 	size_t numf;
 	size_t frame_size;
-	struct data_chunk sgl[0];
+	struct data_chunk sgl[];
 };
 
 /**
@@ -535,7 +535,7 @@ struct dmaengine_unmap_data {
 	struct device *dev;
 	struct kref kref;
 	size_t len;
-	dma_addr_t addr[0];
+	dma_addr_t addr[];
 };
 
 struct dma_async_tx_descriptor;
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index ce0b5fbf239d..3f0b19dcfae7 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -46,7 +46,7 @@ struct fscache_cache_tag {
 	unsigned long		flags;
 #define FSCACHE_TAG_RESERVED	0		/* T if tag is reserved for a cache */
 	atomic_t		usage;
-	char			name[0];	/* tag name */
+	char			name[];	/* tag name */
 };
 
 /*
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 1776eb2e43a4..ea67910ae6b7 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -208,7 +208,7 @@ struct crash_mem_range {
 struct crash_mem {
 	unsigned int max_nr_ranges;
 	unsigned int nr_ranges;
-	struct crash_mem_range ranges[0];
+	struct crash_mem_range ranges[];
 };
 
 extern int crash_exclude_mem_range(struct crash_mem *mem,
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 594265bfd390..e210af75ee38 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -161,7 +161,7 @@ struct kretprobe_instance {
 	kprobe_opcode_t *ret_addr;
 	struct task_struct *task;
 	void *fp;
-	char data[0];
+	char data[];
 };
 
 struct kretprobe_blackpoint {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 62ec926c78a0..d564855243d8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -409,7 +409,7 @@ struct kvm_irq_routing_table {
 	 * Array indexed by gsi. Each entry contains list of irq chips
 	 * the gsi is connected to.
 	 */
-	struct hlist_head map[0];
+	struct hlist_head map[];
 };
 #endif
 
diff --git a/include/linux/libata.h b/include/linux/libata.h
index af832852e620..8bf5e59a7859 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -609,7 +609,7 @@ struct ata_host {
 	struct task_struct	*eh_owner;
 
 	struct ata_port		*simplex_claimed;	/* channel owning the DMA */
-	struct ata_port		*ports[0];
+	struct ata_port		*ports[];
 };
 
 struct ata_queued_cmd {
diff --git a/include/linux/sctp.h b/include/linux/sctp.h
index 8ccd82105de8..76731230bbc5 100644
--- a/include/linux/sctp.h
+++ b/include/linux/sctp.h
@@ -221,7 +221,7 @@ struct sctp_datahdr {
 	__be16 stream;
 	__be16 ssn;
 	__u32 ppid;
-	__u8  payload[0];
+	__u8  payload[];
 };
 
 struct sctp_data_chunk {
@@ -269,7 +269,7 @@ struct sctp_inithdr {
 	__be16 num_outbound_streams;
 	__be16 num_inbound_streams;
 	__be32 initial_tsn;
-	__u8  params[0];
+	__u8  params[];
 };
 
 struct sctp_init_chunk {
@@ -299,13 +299,13 @@ struct sctp_cookie_preserve_param {
 /* Section 3.3.2.1 Host Name Address (11) */
 struct sctp_hostname_param {
 	struct sctp_paramhdr param_hdr;
-	uint8_t hostname[0];
+	uint8_t hostname[];
 };
 
 /* Section 3.3.2.1 Supported Address Types (12) */
 struct sctp_supported_addrs_param {
 	struct sctp_paramhdr param_hdr;
-	__be16 types[0];
+	__be16 types[];
 };
 
 /* ADDIP Section 3.2.6 Adaptation Layer Indication */
@@ -317,25 +317,25 @@ struct sctp_adaptation_ind_param {
 /* ADDIP Section 4.2.7 Supported Extensions Parameter */
 struct sctp_supported_ext_param {
 	struct sctp_paramhdr param_hdr;
-	__u8 chunks[0];
+	__u8 chunks[];
 };
 
 /* AUTH Section 3.1 Random */
 struct sctp_random_param {
 	struct sctp_paramhdr param_hdr;
-	__u8 random_val[0];
+	__u8 random_val[];
 };
 
 /* AUTH Section 3.2 Chunk List */
 struct sctp_chunks_param {
 	struct sctp_paramhdr param_hdr;
-	__u8 chunks[0];
+	__u8 chunks[];
 };
 
 /* AUTH Section 3.3 HMAC Algorithm */
 struct sctp_hmac_algo_param {
 	struct sctp_paramhdr param_hdr;
-	__be16 hmac_ids[0];
+	__be16 hmac_ids[];
 };
 
 /* RFC 2960.  Section 3.3.3 Initiation Acknowledgement (INIT ACK) (2):
@@ -350,7 +350,7 @@ struct sctp_initack_chunk {
 /* Section 3.3.3.1 State Cookie (7) */
 struct sctp_cookie_param {
 	struct sctp_paramhdr p;
-	__u8 body[0];
+	__u8 body[];
 };
 
 /* Section 3.3.3.1 Unrecognized Parameters (8) */
@@ -384,7 +384,7 @@ struct sctp_sackhdr {
 	__be32 a_rwnd;
 	__be16 num_gap_ack_blocks;
 	__be16 num_dup_tsns;
-	union sctp_sack_variable variable[0];
+	union sctp_sack_variable variable[];
 };
 
 struct sctp_sack_chunk {
@@ -436,7 +436,7 @@ struct sctp_shutdown_chunk {
 struct sctp_errhdr {
 	__be16 cause;
 	__be16 length;
-	__u8  variable[0];
+	__u8  variable[];
 };
 
 struct sctp_operr_chunk {
@@ -594,7 +594,7 @@ struct sctp_fwdtsn_skip {
 
 struct sctp_fwdtsn_hdr {
 	__be32 new_cum_tsn;
-	struct sctp_fwdtsn_skip skip[0];
+	struct sctp_fwdtsn_skip skip[];
 };
 
 struct sctp_fwdtsn_chunk {
@@ -611,7 +611,7 @@ struct sctp_ifwdtsn_skip {
 
 struct sctp_ifwdtsn_hdr {
 	__be32 new_cum_tsn;
-	struct sctp_ifwdtsn_skip skip[0];
+	struct sctp_ifwdtsn_skip skip[];
 };
 
 struct sctp_ifwdtsn_chunk {
@@ -658,7 +658,7 @@ struct sctp_addip_param {
 
 struct sctp_addiphdr {
 	__be32	serial;
-	__u8	params[0];
+	__u8	params[];
 };
 
 struct sctp_addip_chunk {
@@ -718,7 +718,7 @@ struct sctp_addip_chunk {
 struct sctp_authhdr {
 	__be16 shkey_id;
 	__be16 hmac_id;
-	__u8   hmac[0];
+	__u8   hmac[];
 };
 
 struct sctp_auth_chunk {
@@ -733,7 +733,7 @@ struct sctp_infox {
 
 struct sctp_reconf_chunk {
 	struct sctp_chunkhdr chunk_hdr;
-	__u8 params[0];
+	__u8 params[];
 };
 
 struct sctp_strreset_outreq {
@@ -741,13 +741,13 @@ struct sctp_strreset_outreq {
 	__be32 request_seq;
 	__be32 response_seq;
 	__be32 send_reset_at_tsn;
-	__be16 list_of_streams[0];
+	__be16 list_of_streams[];
 };
 
 struct sctp_strreset_inreq {
 	struct sctp_paramhdr param_hdr;
 	__be32 request_seq;
-	__be16 list_of_streams[0];
+	__be16 list_of_streams[];
 };
 
 struct sctp_strreset_tsnreq {
diff --git a/include/linux/tifm.h b/include/linux/tifm.h
index 299cbb8c63bb..44073d06710f 100644
--- a/include/linux/tifm.h
+++ b/include/linux/tifm.h
@@ -124,7 +124,7 @@ struct tifm_adapter {
 	int                 (*has_ms_pif)(struct tifm_adapter *fm,
 					  struct tifm_dev *sock);
 
-	struct tifm_dev     *sockets[0];
+	struct tifm_dev     *sockets[];
 };
 
 struct tifm_adapter *tifm_alloc_adapter(unsigned int num_sockets,