Re: [PATCH 1/3] IB/srp: Remove target from list before freeing Scsi_Host structure

[Jack Wang <jinpu.wang-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>]

On 10/10/2013 01:50 PM, Bart Van Assche wrote:
> From: Vu Pham <vuhuong-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> 
> Remove an SRP target from the SRP target list before invoking the
> last scsi_host_put() call. This change is necessary because that
> last put frees the memory that holds the srp_target_port structure.
> 
> This patch prevents that the following kernel oops can be triggered:
> 
> RIP: 0010:[<ffffffff810b00d0>] __lock_acquire+0x500/0x1570
> Call Trace:
>  [<ffffffff810b11e4>] lock_acquire+0xa4/0x120
>  [<ffffffff81531206>] _spin_lock+0x36/0x70
>  [<ffffffffa01b6d8f>] srp_remove_work+0xef/0x180 [ib_srp]
>  [<ffffffff8109125c>] worker_thread+0x21c/0x3d0
>  [<ffffffff81096e86>] kthread+0x96/0xa0
>  [<ffffffff8100c20a>] child_rip+0xa/0x20
> 
> Signed-off-by: Vu Pham <vuhuong-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> [bvanassche: Modified path description and CC'ed stable]
> Signed-off-by: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
> Cc: David Dillow <dillowda-1Heg1YXhbW8@public.gmane.org>
> Cc: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Cc: Sebastian Riemer <sebastian.riemer-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
> Cc: Jack Wang <jinpu.wang-EIkl63zCoXaH+58JC4qpiA@public.gmane.org>
> Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
> ---
>  drivers/infiniband/ulp/srp/ib_srp.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
> index f93baf8..f1318a8 100644
> --- a/drivers/infiniband/ulp/srp/ib_srp.c
> +++ b/drivers/infiniband/ulp/srp/ib_srp.c
> @@ -534,6 +534,11 @@ static void srp_remove_target(struct srp_target_port *target)
>  	ib_destroy_cm_id(target->cm_id);
>  	srp_free_target_ib(target);
>  	srp_free_req_data(target);
> +
> +	spin_lock(&target->srp_host->target_lock);
> +	list_del(&target->list);
> +	spin_unlock(&target->srp_host->target_lock);
> +
>  	scsi_host_put(target->scsi_host);
>  }
>  
> @@ -545,10 +550,6 @@ static void srp_remove_work(struct work_struct *work)
>  	WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);
>  
>  	srp_remove_target(target);
> -
> -	spin_lock(&target->srp_host->target_lock);
> -	list_del(&target->list);
> -	spin_unlock(&target->srp_host->target_lock);
>  }

Or move the 3 line code on top of srp_remove_target(target);?
Patch looks good.

Jack
>  
>  static void srp_rport_delete(struct srp_rport *rport)
> 

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