Re: [PATCH 1 08/25] hpsa: fix hpsa_adjust_hpsa_scsi_table

[Tomas Henzl <thenzl@redhat.com>]

On 28.10.2015 23:05, Don Brace wrote:
> Fix a NULL pointer issue in the driver when devices are removed
> during a reset.
>
> Signed-off-by: Don Brace <don.brace@pmcs.com>
> ---
>  drivers/block/cciss.h |    1 +
>  drivers/scsi/hpsa.c   |   16 ++++++++++++++++
>  drivers/scsi/hpsa.h   |    1 +
>  3 files changed, 18 insertions(+)
>
> diff --git a/drivers/block/cciss.h b/drivers/block/cciss.h
> index 7fda30e..f8b8c6b 100644
> --- a/drivers/block/cciss.h
> +++ b/drivers/block/cciss.h
> @@ -155,6 +155,7 @@ struct ctlr_info
>  	size_t reply_pool_size;
>  	unsigned char reply_pool_wraparound;
>  	u32 *blockFetchTable;
> +	u8 reset_in_progress;
>  };
>  
>  /*  Defining the diffent access_methods
> diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
> index ced0d4c..08a761c 100644
> --- a/drivers/scsi/hpsa.c
> +++ b/drivers/scsi/hpsa.c
> @@ -1670,6 +1670,15 @@ static void adjust_hpsa_scsi_table(struct ctlr_info *h, int hostno,
>  	int nadded, nremoved;
>  	struct Scsi_Host *sh = NULL;
>  
> +	/*
> +	 * A reset can cause a device status to change
> +	 * re-schedule the scan to see what happened.
> +	 */
> +	if (h->reset_in_progress) {
> +		h->drv_req_rescan = 1;
> +		return;
> +	}
> +

If another process start the reset at this point will you get the
the same Null pointer issue as before? Isn't some kind of
exclusive access protection needed ?

-tm

>  	added = kzalloc(sizeof(*added) * HPSA_MAX_DEVICES, GFP_KERNEL);
>  	removed = kzalloc(sizeof(*removed) * HPSA_MAX_DEVICES, GFP_KERNEL);
>  
> @@ -1780,6 +1789,10 @@ static void adjust_hpsa_scsi_table(struct ctlr_info *h, int hostno,
>  		goto free_and_out;
>  
>  	sh = h->scsi_host;
> +	if (sh == NULL) {
> +		dev_warn(&h->pdev->dev, "%s: scsi_host is null\n", __func__);
> +		return;
> +	}
>  	/* Notify scsi mid layer of any removed devices */
>  	for (i = 0; i < nremoved; i++) {
>  		if (removed[i] == NULL)
> @@ -5243,12 +5256,15 @@ static int hpsa_eh_device_reset_handler(struct scsi_cmnd *scsicmd)
>  
>  	hpsa_show_dev_msg(KERN_WARNING, h, dev, "resetting");
>  
> +	h->reset_in_progress = 1;
> +
>  	/* send a reset to the SCSI LUN which the command was sent to */
>  	rc = hpsa_do_reset(h, dev, dev->scsi3addr, HPSA_RESET_TYPE_LUN,
>  			   DEFAULT_REPLY_QUEUE);
>  	snprintf(msg, sizeof(msg), "reset %s",
>  		 rc == 0 ? "completed successfully" : "failed");
>  	hpsa_show_dev_msg(KERN_WARNING, h, dev, msg);
> +	h->reset_in_progress = 0;
>  	return rc == 0 ? SUCCESS : FAILED;
>  }
>  
> diff --git a/drivers/scsi/hpsa.h b/drivers/scsi/hpsa.h
> index b173c0e..dc113c1a 100644
> --- a/drivers/scsi/hpsa.h
> +++ b/drivers/scsi/hpsa.h
> @@ -271,6 +271,7 @@ struct ctlr_info {
>  	wait_queue_head_t abort_cmd_wait_queue;
>  	wait_queue_head_t event_sync_wait_queue;
>  	struct mutex reset_mutex;
> +	u8 reset_in_progress;
>  };
>  
>  struct offline_device_entry {
>
> --
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