Re: [2.6 patch][1/3] ipc/ BUG -> BUG_ON conversions

[Kyle Moffett]

On Aug 28, 2004, at 11:15, Adrian Bunk wrote:
> The patch below does BUG -> BUG_ON conversions in ipc/ .
> --- linux-2.6.9-rc1-mm1-full-3.4/ipc/shm.c.old	2004-08-28 
> 15:55:28.000000000 +0200
> +++ linux-2.6.9-rc1-mm1-full-3.4/ipc/shm.c	2004-08-28 
> 16:02:56.000000000 +0200
> @@ -86,8 +86,7 @@
>  static inline void shm_inc (int id) {
>  	struct shmid_kernel *shp;
>
> -	if(!(shp = shm_lock(id)))
> -		BUG();
> +	BUG_ON(!(shp = shm_lock(id)));

This won't work:

With debugging mode:
if (unlikely(!(shp = shm_lock(id)))) BUG();

Without debugging mode:
do { } while(0)

Anything you put in BUG_ON() must *NOT* have side effects.


>  	shp->shm_atim = get_seconds();
>  	shp->shm_lprid = current->tgid;
>  	shp->shm_nattch++;
> @@ -137,8 +136,7 @@
>
>  	down (&shm_ids.sem);
>  	/* remove from the list of attaches of the shm segment */
> -	if(!(shp = shm_lock(id)))
> -		BUG();
> +	BUG_ON(!(shp = shm_lock(id)));

Same here

>  	shp->shm_lprid = current->tgid;
>  	shp->shm_dtim = get_seconds();
>  	shp->shm_nattch--;
> @@ -744,8 +741,7 @@
>  	up_write(&current->mm->mmap_sem);
>
>  	down (&shm_ids.sem);
> -	if(!(shp = shm_lock(shmid)))
> -		BUG();
> +	BUG_ON(!(shp = shm_lock(shmid)));

And here

>  	shp->shm_nattch--;
>  	if(shp->shm_nattch == 0 &&
>  	   shp->shm_flags & SHM_DEST)

Cheers,
Kyle Moffett

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