On Wed, Feb 05, 2025 at 03:51:35PM +1030, Gustavo A. R. Silva wrote:
> --- a/include/linux/tty_buffer.h
> +++ b/include/linux/tty_buffer.h
> @@ -8,19 +8,24 @@
>  #include <linux/workqueue.h>
>  
>  struct tty_buffer {
> -     union {
> -             struct tty_buffer *next;
> -             struct llist_node free;
> -     };
> -     unsigned int used;
> -     unsigned int size;
> -     unsigned int commit;
> -     unsigned int lookahead;         /* Lazy update on recv, can become less 
> than "read" */
> -     unsigned int read;
> -     bool flags;
> +     /* New members MUST be added within the struct_group() macro below. */

Why?  You need to say that here otherwise we aren't going to know.

> +     struct_group_tagged(tty_buffer_hdr, __hdr,
> +             union {
> +                     struct tty_buffer *next;
> +                     struct llist_node free;
> +             };
> +             unsigned int used;
> +             unsigned int size;
> +             unsigned int commit;
> +             unsigned int lookahead;         /* Lazy update on recv, can 
> become less than "read" */
> +             unsigned int read;
> +             bool flags;
> +     );
>       /* Data points here */
>       u8 data[] __aligned(sizeof(unsigned long));
>  };
> +static_assert(offsetof(struct tty_buffer, data) == sizeof(struct 
> tty_buffer_hdr),
> +              "struct member likely outside of struct_group_tagged()");
>  
>  static inline u8 *char_buf_ptr(struct tty_buffer *b, unsigned int ofs)
>  {
> @@ -33,15 +38,15 @@ static inline u8 *flag_buf_ptr(struct tty_buffer *b, 
> unsigned int ofs)
>  }
>  
>  struct tty_bufhead {
> -     struct tty_buffer *head;        /* Queue head */
> -     struct work_struct work;
> -     struct mutex       lock;
> -     atomic_t           priority;
> -     struct tty_buffer sentinel;
> -     struct llist_head free;         /* Free queue head */
> -     atomic_t           mem_used;    /* In-use buffers excluding free list */
> -     int                mem_limit;
> -     struct tty_buffer *tail;        /* Active buffer */
> +     struct tty_buffer       *head;  /* Queue head */
> +     struct work_struct      work;
> +     struct mutex            lock;
> +     atomic_t                priority;
> +     struct tty_buffer_hdr   sentinel;
> +     struct llist_head       free;           /* Free queue head */
> +     atomic_t                mem_used;    /* In-use buffers excluding free 
> list */
> +     int                     mem_limit;
> +     struct tty_buffer       *tail;  /* Active buffer */
>  };

Did you change anything in this structure?  By reformatting it, it's
hard to tell what happened, so please don't do that :(

thanks,

greg k-h

Reply via email to