Re: C++ pushback

Xavier Bestel
2006-04-25T08:15:55Z

On Tue, 2006-04-25 at 00:16, J.A. Magallon wrote:

> Tell me what is the difference between:
>
>
> sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
> if (!sbi)
> return -ENOMEM;
> sb->s_fs_info = sbi;
> memset(sbi, 0, sizeof(*sbi));
> sbi->s_mount_opt = 0;
> sbi->s_resuid = EXT3_DEF_RESUID;
> sbi->s_resgid = EXT3_DEF_RESGID;
>
> and
>
> SuperBlock() : s_mount_opt(0), s_resuid(EXT3_DEF_RESUID), s_resgid(EXT3_DEF_RESGID)
> {}
>
> ...
> sbi = new SuperBlock;
> if (!sbi)
> return -ENOMEM;

In the first case you know that exactely *one* kmalloc(GFP_KERNEL)
occurs. In the second case you have to browse SuperBlock's constructor
to check if it allocates things, needs to run with/without interrupts,
PREEMPT, whatever... (not even talking about exceptions).

Xav