Merge tag 'flex-array-conversions-5.8-rc2' of git://git.kernel.org/pu…

…b/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 7649773 ("cxgb3/l2t: Fix undefined behaviour")
[4] commit f2cd32a ("rndis_wlan: Remove logically dead code")
[5] commit ab91c2a ("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
  ...

arch/ia64/kernel/unwind_i.h

@@ -42,7 +42,7 @@ enum unw_register_index {
 
 struct unw_info_block {
 	u64 header;
-	u64 desc[0];		/* unwind descriptors */
+	u64 desc[];		/* unwind descriptors */
 	/* personality routine and language-specific data follow behind descriptors */
 };
 

block/partitions/ldm.h

@@ -93,7 +93,7 @@ struct frag {				/* VBLK Fragment handling */
 	u8		num;		/* Total number of records */
 	u8		rec;		/* This is record number n */
 	u8		map;		/* Which portions are in use */
-	u8		data[0];
+	u8		data[];
 };
 
 /* In memory LDM database structures. */

drivers/amba/tegra-ahb.c

@@ -120,7 +120,7 @@ static const u32 tegra_ahb_gizmo[] = {
 struct tegra_ahb {
 	void __iomem	*regs;
 	struct device	*dev;
-	u32		ctx[0];
+	u32		ctx[];
 };
 
 static inline u32 gizmo_readl(struct tegra_ahb *ahb, u32 offset)

drivers/block/drbd/drbd_int.h

@@ -620,7 +620,7 @@ struct fifo_buffer {
 	unsigned int head_index;
 	unsigned int size;
 	int total; /* sum of all values */
-	int values[0];
+	int values[];
 };
 extern struct fifo_buffer *fifo_alloc(unsigned int fifo_size);
 

drivers/block/drbd/drbd_protocol.h

@@ -271,7 +271,7 @@ struct p_rs_param {
 	u32 resync_rate;
 
 	      /* Since protocol version 88 and higher. */
-	char verify_alg[0];
+	char verify_alg[];
 } __packed;
 
 struct p_rs_param_89 {
@@ -305,7 +305,7 @@ struct p_protocol {
 	u32 two_primaries;
 
 	/* Since protocol version 87 and higher. */
-	char integrity_alg[0];
+	char integrity_alg[];
 
 } __packed;
 
@@ -360,7 +360,7 @@ struct p_sizes {
 	u16	    dds_flags; /* use enum dds_flags here. */
 
 	/* optional queue_limits if (agreed_features & DRBD_FF_WSAME) */
-	struct o_qlim qlim[0];
+	struct o_qlim qlim[];
 } __packed;
 
 struct p_state {
@@ -409,7 +409,7 @@ struct p_compressed_bm {
 	 */
 	u8 encoding;
 
-	u8 code[0];
+	u8 code[];
 } __packed;
 
 struct p_delay_probe93 {

drivers/crypto/chelsio/chcr_crypto.h

@@ -223,7 +223,7 @@ struct chcr_authenc_ctx {
 
 struct __aead_ctx {
 	struct chcr_gcm_ctx gcm[0];
-	struct chcr_authenc_ctx authenc[0];
+	struct chcr_authenc_ctx authenc[];
 };
 
 struct chcr_aead_ctx {
@@ -235,7 +235,7 @@ struct chcr_aead_ctx {
 	u8 nonce[4];
 	u16 hmac_ctrl;
 	u16 mayverify;
-	struct	__aead_ctx ctx[0];
+	struct	__aead_ctx ctx[];
 };
 
 struct hmac_ctx {
@@ -247,7 +247,7 @@ struct hmac_ctx {
 struct __crypto_ctx {
 	struct hmac_ctx hmacctx[0];
 	struct ablk_ctx ablkctx[0];
-	struct chcr_aead_ctx aeadctx[0];
+	struct chcr_aead_ctx aeadctx[];
 };
 
 struct chcr_context {
@@ -257,7 +257,7 @@ struct chcr_context {
 	unsigned int  ntxq;
 	unsigned int  nrxq;
 	struct completion cbc_aes_aio_done;
-	struct __crypto_ctx crypto_ctx[0];
+	struct __crypto_ctx crypto_ctx[];
 };
 
 struct chcr_hctx_per_wr {

drivers/dma/milbeaut-hdmac.c

@@ -77,7 +77,7 @@ struct milbeaut_hdmac_device {
 	struct dma_device ddev;
 	struct clk *clk;
 	void __iomem *reg_base;
-	struct milbeaut_hdmac_chan channels[0];
+	struct milbeaut_hdmac_chan channels[];
 };
 
 static struct milbeaut_hdmac_chan *

drivers/dma/milbeaut-xdmac.c

@@ -74,7 +74,7 @@ struct milbeaut_xdmac_chan {
 struct milbeaut_xdmac_device {
 	struct dma_device ddev;
 	void __iomem *reg_base;
-	struct milbeaut_xdmac_chan channels[0];
+	struct milbeaut_xdmac_chan channels[];
 };
 
 static struct milbeaut_xdmac_chan *

drivers/dma/moxart-dma.c

@@ -127,7 +127,7 @@ struct moxart_desc {
 	unsigned int			dma_cycles;
 	struct virt_dma_desc		vd;
 	uint8_t				es;
-	struct moxart_sg		sg[0];
+	struct moxart_sg		sg[];
 };
 
 struct moxart_chan {

drivers/dma/tegra20-apb-dma.c

@@ -225,7 +225,7 @@ struct tegra_dma {
 	u32				global_pause_count;
 
 	/* Last member of the structure */
-	struct tegra_dma_channel channels[0];
+	struct tegra_dma_channel channels[];
 };
 
 static inline void tdma_write(struct tegra_dma *tdma, u32 reg, u32 val)

drivers/dma/ti/edma.c

@@ -211,7 +211,7 @@ struct edma_desc {
 	u32				residue;
 	u32				residue_stat;
 
-	struct edma_pset		pset[0];
+	struct edma_pset		pset[];
 };
 
 struct edma_cc;

drivers/dma/ti/k3-udma.c

@@ -170,7 +170,7 @@ struct udma_desc {
 	void *metadata; /* pointer to provided metadata buffer (EPIP, PSdata) */
 
 	unsigned int hwdesc_count;
-	struct udma_hwdesc hwdesc[0];
+	struct udma_hwdesc hwdesc[];
 };
 
 enum udma_chan_state {

drivers/dma/timb_dma.c

@@ -88,7 +88,7 @@ struct timb_dma {
 	struct dma_device	dma;
 	void __iomem		*membase;
 	struct tasklet_struct	tasklet;
-	struct timb_dma_chan	channels[0];
+	struct timb_dma_chan	channels[];
 };
 
 static struct device *chan2dev(struct dma_chan *chan)

drivers/firewire/core-cdev.c

@@ -117,7 +117,7 @@ struct inbound_transaction_resource {
 struct descriptor_resource {
 	struct client_resource resource;
 	struct fw_descriptor descriptor;
-	u32 data[0];
+	u32 data[];
 };
 
 struct iso_resource {

drivers/firewire/core-transaction.c

@@ -620,7 +620,7 @@ struct fw_request {
 	u32 request_header[4];
 	int ack;
 	u32 length;
-	u32 data[0];
+	u32 data[];
 };
 
 static void free_response_callback(struct fw_packet *packet,

drivers/firewire/core.h

@@ -191,7 +191,7 @@ struct fw_node {
 	/* Upper layer specific data. */
 	void *data;
 
-	struct fw_node *ports[0];
+	struct fw_node *ports[];
 };
 
 static inline struct fw_node *fw_node_get(struct fw_node *node)

drivers/firewire/nosy.c

@@ -52,7 +52,7 @@ struct pcl {
 
 struct packet {
 	unsigned int length;
-	char data[0];
+	char data[];
 };
 
 struct packet_buffer {

drivers/firewire/ohci.c

@@ -111,7 +111,7 @@ struct descriptor_buffer {
 	dma_addr_t buffer_bus;
 	size_t buffer_size;
 	size_t used;
-	struct descriptor buffer[0];
+	struct descriptor buffer[];
 };
 
 struct context {

drivers/firmware/dmi-sysfs.c

@@ -262,7 +262,7 @@ struct dmi_system_event_log {
 	u8	header_format;
 	u8	type_descriptors_supported_count;
 	u8	per_log_type_descriptor_length;
-	u8	supported_log_type_descriptos[0];
+	u8	supported_log_type_descriptos[];
 } __packed;
 
 #define DMI_SYSFS_SEL_FIELD(_field) \

drivers/firmware/google/memconsole-coreboot.c

@@ -21,7 +21,7 @@
 struct cbmem_cons {
 	u32 size_dont_access_after_boot;
 	u32 cursor;
-	u8  body[0];
+	u8  body[];
 } __packed;
 
 #define CURSOR_MASK ((1 << 28) - 1)

drivers/firmware/google/vpd.c

@@ -32,7 +32,7 @@ struct vpd_cbmem {
 	u32 version;
 	u32 ro_size;
 	u32 rw_size;
-	u8  blob[0];
+	u8  blob[];
 };
 
 struct vpd_section {

drivers/firmware/iscsi_ibft.c

@@ -104,7 +104,7 @@ struct ibft_control {
 	u16 tgt0_off;
 	u16 nic1_off;
 	u16 tgt1_off;
-	u16 expansion[0];
+	u16 expansion[];
 } __attribute__((__packed__));
 
 struct ibft_initiator {

drivers/firmware/pcdp.h

@@ -103,6 +103,6 @@ struct pcdp {
 	u8			creator_id[4];
 	u32			creator_rev;
 	u32			num_uarts;
-	struct pcdp_uart	uart[0];	/* actual size is num_uarts */
+	struct pcdp_uart	uart[];	/* actual size is num_uarts */
 	/* remainder of table is pcdp_device structures */
 } __attribute__((packed));

drivers/hwtracing/stm/policy.c

@@ -34,7 +34,7 @@ struct stp_policy_node {
 	unsigned int		first_channel;
 	unsigned int		last_channel;
 	/* this is the one that's exposed to the attributes */
-	unsigned char		priv[0];
+	unsigned char		priv[];
 };
 
 void *stp_policy_node_priv(struct stp_policy_node *pn)

drivers/hwtracing/stm/stm.h

@@ -23,7 +23,7 @@ void *stp_policy_node_priv(struct stp_policy_node *pn);
 
 struct stp_master {
 	unsigned int	nr_free;
-	unsigned long	chan_map[0];
+	unsigned long	chan_map[];
 };
 
 struct stm_device {
@@ -42,7 +42,7 @@ struct stm_device {
 	const struct config_item_type		*pdrv_node_type;
 	/* master allocation */
 	spinlock_t		mc_lock;
-	struct stp_master	*masters[0];
+	struct stp_master	*masters[];
 };
 
 #define to_stm_device(_d)				\

drivers/media/usb/pwc/pwc.h

@@ -193,7 +193,7 @@ struct pwc_raw_frame {
 				   decompressor) */
 	__u8   cmd[4];		/* the four byte of the command (in case of
 				   nala, only the first 3 bytes is filled) */
-	__u8   rawframe[0];	/* frame_size = H / 4 * vbandlength */
+	__u8   rawframe[];	/* frame_size = H / 4 * vbandlength */
 } __packed;
 
 /* intermediate buffers with raw data from the USB cam */

drivers/net/can/peak_canfd/peak_pciefd_main.c

@@ -146,7 +146,7 @@ struct pciefd_rx_dma {
 	__le32 irq_status;
 	__le32 sys_time_low;
 	__le32 sys_time_high;
-	struct pucan_rx_msg msg[0];
+	struct pucan_rx_msg msg[];
 } __packed __aligned(4);
 
 /* Tx Link record */
@@ -194,7 +194,7 @@ struct pciefd_board {
 	struct pci_dev *pci_dev;
 	int can_count;
 	spinlock_t cmd_lock;		/* 64-bits cmds must be atomic */
-	struct pciefd_can *can[0];	/* array of network devices */
+	struct pciefd_can *can[];	/* array of network devices */
 };
 
 /* supported device ids. */

drivers/oprofile/cpu_buffer.h

@@ -33,7 +33,7 @@ void flush_cpu_work(void);
 struct op_sample {
 	unsigned long eip;
 	unsigned long event;
-	unsigned long data[0];
+	unsigned long data[];
 };
 
 struct op_entry;

drivers/phy/samsung/phy-samsung-usb2.h

@@ -43,7 +43,7 @@ struct samsung_usb2_phy_driver {
 	struct regmap *reg_pmu;
 	struct regmap *reg_sys;
 	spinlock_t lock;
-	struct samsung_usb2_phy_instance instances[0];
+	struct samsung_usb2_phy_instance instances[];
 };
 
 struct samsung_usb2_common_phy {

drivers/rapidio/rio-scan.c

@@ -39,7 +39,7 @@ struct rio_id_table {
 	u16 start;	/* logical minimal id */
 	u32 max;	/* max number of IDs in table */
 	spinlock_t lock;
-	unsigned long table[0];
+	unsigned long table[];
 };
 
 static int next_destid = 0;

drivers/soc/ti/knav_qmss.h

@@ -67,7 +67,7 @@ struct knav_reg_config {
 	u32		link_ram_size0;
 	u32		link_ram_base1;
 	u32		__pad2[2];
-	u32		starvation[0];
+	u32		starvation[];
 };
 
 struct knav_reg_region {

drivers/w1/w1_netlink.h

@@ -73,7 +73,7 @@ struct w1_netlink_msg
 			__u32		res;
 		} mst;
 	} id;
-	__u8				data[0];
+	__u8				data[];
 };
 
 /**
@@ -122,7 +122,7 @@ struct w1_netlink_cmd
 	__u8				cmd;
 	__u8				res;
 	__u16				len;
-	__u8				data[0];
+	__u8				data[];
 };
 
 #ifdef __KERNEL__

fs/aio.c

@@ -67,7 +67,7 @@ struct aio_ring {
 	unsigned	header_length;	/* size of aio_ring */
 
 
-	struct io_event		io_events[0];
+	struct io_event		io_events[];
 }; /* 128 bytes + ring size */
 
 /*

fs/jffs2/nodelist.h

@@ -259,7 +259,7 @@ struct jffs2_full_dirent
 	uint32_t ino; /* == zero for unlink */
 	unsigned int nhash;
 	unsigned char type;
-	unsigned char name[0];
+	unsigned char name[];
 };
 
 /*