Merge tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull flexible-array member conversion from Gustavo Silva: "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] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member convertions) will also help to get completely rid of those sorts of issues. Notice that all of these patches have been baking in linux-next for quite a while now and, 238 more of these patches have already been merged into 5.7-rc1. There are a couple hundred more of these issues waiting to be addressed in the whole codebase" [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] KSPP#21 [3] commit 7649773 ("cxgb3/l2t: Fix undefined behaviour") * tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux: (28 commits) xattr.h: Replace zero-length array with flexible-array member uapi: linux: fiemap.h: Replace zero-length array with flexible-array member uapi: linux: dlm_device.h: Replace zero-length array with flexible-array member tpm_eventlog.h: Replace zero-length array with flexible-array member ti_wilink_st.h: Replace zero-length array with flexible-array member swap.h: Replace zero-length array with flexible-array member skbuff.h: Replace zero-length array with flexible-array member sched: topology.h: Replace zero-length array with flexible-array member rslib.h: Replace zero-length array with flexible-array member rio.h: Replace zero-length array with flexible-array member posix_acl.h: Replace zero-length array with flexible-array member platform_data: wilco-ec.h: Replace zero-length array with flexible-array member memcontrol.h: Replace zero-length array with flexible-array member list_lru.h: Replace zero-length array with flexible-array member lib: cpu_rmap: Replace zero-length array with flexible-array member irq.h: Replace zero-length array with flexible-array member ihex.h: Replace zero-length array with flexible-array member igmp.h: Replace zero-length array with flexible-array member genalloc.h: Replace zero-length array with flexible-array member ethtool.h: Replace zero-length array with flexible-array member ...

Author: torvalds

include/linux/bio.h

@@ -319,7 +319,7 @@ struct bio_integrity_payload {
 struct work_structbip_work;/* I/O completion */
 
 struct bio_vec*bip_vec;
-struct bio_vecbip_inline_vecs[0];/* embedded bvec array */
+struct bio_vecbip_inline_vecs[];/* embedded bvec array */
 };
 
 #if defined(CONFIG_BLK_DEV_INTEGRITY)

include/linux/blk-mq.h

@@ -173,7 +173,7 @@ struct blk_mq_hw_ctx {
  * blocking (BLK_MQ_F_BLOCKING). Must be the last member - see also
  * blk_mq_hw_ctx_size().
  */
-struct srcu_structsrcu[0];
+struct srcu_structsrcu[];
 };
 
 /**

include/linux/blk_types.h

@@ -198,7 +198,7 @@ struct bio {
  * double allocations for a small number of bio_vecs. This member
  * MUST obviously be kept at the very end of the bio.
  */
-struct bio_vecbi_inline_vecs[0];
+struct bio_vecbi_inline_vecs[];
 };
 
 #define BIO_RESET_BYTESoffsetof(struct bio, bi_max_vecs)

include/linux/can/dev/peak_canfd.h

@@ -189,7 +189,7 @@ struct __packed pucan_rx_msg {
 u8client;
 __le16flags;
 __le32can_id;
-u8d[0];
+u8d[];
 };
 
 /* uCAN error types */
@@ -266,7 +266,7 @@ struct __packed pucan_tx_msg {
 u8client;
 __le16flags;
 __le32can_id;
-u8d[0];
+u8d[];
 };
 
 /* build the cmd opcode_channel field with respect to the correct endianness */

include/linux/cpu_rmap.h

@@ -28,7 +28,7 @@ struct cpu_rmap {
 struct {
 u16index;
 u16dist;
-}near[0];
+}near[];
 };
 #define CPU_RMAP_DIST_INF 0xffff
 

include/linux/digsig.h

@@ -29,7 +29,7 @@ struct pubkey_hdr {
 uint32_ttimestamp;/* key made, always 0 for now */
 uint8_talgo;
 uint8_tnmpi;
-charmpi[0];
+charmpi[];
 } __packed;
 
 struct signature_hdr {
@@ -39,7 +39,7 @@ struct signature_hdr {
 uint8_thash;
 uint8_tkeyid[8];
 uint8_tnmpi;
-charmpi[0];
+charmpi[];
 } __packed;
 
 #if defined(CONFIG_SIGNATURE) || defined(CONFIG_SIGNATURE_MODULE)

include/linux/dirent.h

@@ -7,7 +7,7 @@ struct linux_dirent64 {
 s64d_off;
 unsigned shortd_reclen;
 unsigned chard_type;
-chard_name[0];
+chard_name[];
 };
 
 #endif

include/linux/enclosure.h

@@ -101,7 +101,7 @@ struct enclosure_device {
 struct device edev;
 struct enclosure_component_callbacks *cb;
 int components;
-struct enclosure_component component[0];
+struct enclosure_component component[];
 };
 
 static inline struct enclosure_device *

include/linux/energy_model.h

@@ -36,7 +36,7 @@ struct em_cap_state {
 struct em_perf_domain {
 struct em_cap_state *table;
 int nr_cap_states;
-unsigned long cpus[0];
+unsigned long cpus[];
 };
 
 #ifdef CONFIG_ENERGY_MODEL

include/linux/ethtool.h

@@ -35,7 +35,7 @@ struct compat_ethtool_rxnfc {
 compat_u64data;
 struct compat_ethtool_rx_flow_spec fs;
 u32rule_cnt;
-u32rule_locs[0];
+u32rule_locs[];
 };
 
 #endif /* CONFIG_COMPAT */
@@ -462,7 +462,7 @@ int ethtool_check_ops(const struct ethtool_ops *ops);
 
 struct ethtool_rx_flow_rule {
 struct flow_rule*rule;
-unsigned longpriv[0];
+unsigned longpriv[];
 };
 
 struct ethtool_rx_flow_spec_input {