Re: [PATCH RESEND] csiostor:Fix locking issues in the function csio_scsim_cleanup_io_lnode

Re: [PATCH RESEND] csiostor:Fix locking issues in the function csio_scsim_cleanup_io_lnode

[Jens Axboe]

On 12/29/2015 11:23 AM, Nicholas Krause wrote:
> This fixes locking issues in the function csio_scsim_cleanup_io_lnode
> by locking around the call to the function csio_csci_gather_active_ios
> with the function pair spin_lock_irq/spin_unlock_irq as any function
> calling this particular function must do in order to avoid concurrent
> threads of execution on the passed structure pointer of type csio_hw
> as this structure pointer can be shared across mutliple threads in the
> kernel.
>
> Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
> ---
>   drivers/scsi/csiostor/csio_scsi.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/scsi/csiostor/csio_scsi.c b/drivers/scsi/csiostor/csio_scsi.c
> index 2c4562d..c318855 100644
> --- a/drivers/scsi/csiostor/csio_scsi.c
> +++ b/drivers/scsi/csiostor/csio_scsi.c
> @@ -1327,7 +1327,9 @@ csio_scsim_cleanup_io_lnode(struct csio_scsim *scm, struct csio_lnode *ln)
>   	sld.level = CSIO_LEV_LNODE;
>   	sld.lnode = ln;
>   	INIT_LIST_HEAD(&ln->cmpl_q);
> +	spin_lock_irq(&hw->lock);
>   	csio_scsi_gather_active_ios(scm, &sld, &ln->cmpl_q);
> +	spin_unlock_irq(&hw->lock);

All the callers grab that lock, you've just added a deadlock instead.

Nick, I've said this before and I'll say this again. Stop sending me 
patches. They are all untested and broken, you are wasting peoples time.

-- 
Jens Axboe