Re: FAILED: patch "[PATCH] Revert "scsi: Fix a bdi reregistration race"" failed to apply to 3.14-stable tree

[Bart Van Assche <bart.vanassche@sandisk.com>]

Hi Greg,

The original patch ("scsi: Fix a bdi reregistration race"; commit ID 
bf2cf3baa20b0a6cd2d08707ef05dc0e992a8aa0) has a "Cc: stable" tag but it 
seems like that patch did not yet make it into the linux-3.14.y nor into 
the linux-3.10.y branch? This means that it is safe to skip the revert. 
But please make sure that the original patch does not get added to any 
of the stable trees later on ...

Thanks,

Bart.

On 02/23/2016 04:32 PM, gregkh@linuxfoundation.org wrote:
>
> The patch below does not apply to the 3.14-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
>  From e619e6cbecb7fe97a924d625e848605333457b13 Mon Sep 17 00:00:00 2001
> From: Bart Van Assche <bart.vanassche@sandisk.com>
> Date: Fri, 20 Nov 2015 14:11:01 -0800
> Subject: [PATCH] Revert "scsi: Fix a bdi reregistration race"
>
> The SCSI sd driver probes SCSI devices asynchronously. The sd_remove()
> function, called indirectly by device_del(), waits until asynchronous
> probing has finished. Since the block layer queue must only be cleaned
> up after probing has finished, device_del() has to be called before
> blk_cleanup_queue(). Hence revert commit bf2cf3baa20b.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: James Bottomley <JBottomley@Odin.com>
>
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index 8d2312239ae0..f5ace2bfc6db 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -1110,7 +1110,9 @@ void __scsi_remove_device(struct scsi_device *sdev)
>   		device_unregister(&sdev->sdev_dev);
>   		transport_remove_device(dev);
>   		scsi_dh_remove_device(sdev);
> -	}
> +		device_del(dev);
> +	} else
> +		put_device(&sdev->sdev_dev);
>
>   	/*
>   	 * Stop accepting new requests and wait until all queuecommand() and
> @@ -1121,16 +1123,6 @@ void __scsi_remove_device(struct scsi_device *sdev)
>   	blk_cleanup_queue(sdev->request_queue);
>   	cancel_work_sync(&sdev->requeue_work);
>
> -	/*
> -	 * Remove the device after blk_cleanup_queue() has been called such
> -	 * a possible bdi_register() call with the same name occurs after
> -	 * blk_cleanup_queue() has called bdi_destroy().
> -	 */
> -	if (sdev->is_visible)
> -		device_del(dev);
> -	else
> -		put_device(&sdev->sdev_dev);
> -
>   	if (sdev->host->hostt->slave_destroy)
>   		sdev->host->hostt->slave_destroy(sdev);
>   	transport_destroy_device(dev);
>
>