Commit 13402837 authored Apr 19, 2020 by Linus Torvalds

Merge tag 'flexible-array-member-5.7-rc2' of...

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] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("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
  ...

parents 50cc09c1 43951585

include/linux/bio.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -319,7 +319,7 @@ struct bio_integrity_payload {
		struct work_struct bip_work; /* I/O completion */

		struct bio_vec *bip_vec;
		struct bio_vec bip_inline_vecs[0];/* embedded bvec array */
		struct bio_vec bip_inline_vecs[];/* embedded bvec array */
		};

		#if defined(CONFIG_BLK_DEV_INTEGRITY)

include/linux/blk-mq.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -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_struct srcu[0];
		struct srcu_struct srcu[];
		};

		/**

include/linux/blk_types.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -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_vec bi_inline_vecs[0];
		struct bio_vec bi_inline_vecs[];
		};

		#define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs)

include/linux/can/dev/peak_canfd.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -189,7 +189,7 @@ struct __packed pucan_rx_msg {
		u8 client;
		__le16 flags;
		__le32 can_id;
		u8 d[0];
		u8 d[];
		};

		/* uCAN error types */
		@@ -266,7 +266,7 @@ struct __packed pucan_tx_msg {
		u8 client;
		__le16 flags;
		__le32 can_id;
		u8 d[0];
		u8 d[];
		};

		/* build the cmd opcode_channel field with respect to the correct endianness */

include/linux/cpu_rmap.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -28,7 +28,7 @@ struct cpu_rmap {
		struct {
		u16 index;
		u16 dist;
		} near[0];
		} near[];
		};
		#define CPU_RMAP_DIST_INF 0xffff

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