Re: [PATCH scsi] Add NULL checking of return value fromscsi_cmd_to_driver()

[Li Zhong]

On Mon, 2012-09-24 at 09:44 +0400, James Bottomley wrote:
> On Mon, 2012-09-24 at 13:30 +0800, Li Zhong wrote:
> > Just noticed that after commit 919f797, it is possible that 
> > scsi_cmd_to_driver() returns NULL. This patch adds the NULL checking for drv 
> > returned from the above function. 
> > 
> > Maybe it is not possible at run time, but from the code itself, we'd better
> > have this check?  
> 
> There's not much point having a check that never trips, unless it's an
> assert, in which case a NULL deref does that.  All it does is add
> pointless instructions to the critical path.  only REQ_TYPE_BLOCK_PC
> commands can be submitted without a driver, so the check above would
> seem to preclude that.

Hi James, 

Thank you, it sounds reasonable to me. Let's drop it. 

Thanks, Zhong

> James
> 
> 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/