Re: [PATCH RESEND v2 2/5] block: disk_events: introduce event flags

[Hannes Reinecke <hare@suse.de>]

On 3/22/19 11:43 PM, Martin Wilck wrote:
> Currently, an empty disk->events field tells the block layer not to forward
> media change events to user space. This was done in
> commit 7c88a168da80 ("block: don't propagate unlisted DISK_EVENTs to userland")
> in order to avoid events from "fringe" drivers to be forwarded to user
> space. By doing so, the block layer lost the information which events were
> supported by a particular block device, and most importantly, whether or
> not a given device supports media change events at all.
> 
> Prepare for not interpreting the "events" field this way in the future any
> more. This is done by adding two flag bits that can be set to have the
> device treated like one that has the "events" field set to a non-zero value
> before. This applies only to the sd and sr drivers, which are changed to
> set the new flags.
> 
> The new flags are DISK_EVENT_FLAG_POLL to enforce polling of the device for
> synchronous events, and DISK_EVENT_FLAG_UEVENT to tell the blocklayer to
> generate udev events from kernel events. They can easily be fit in the int
> reserved for event bits.
> 
> This patch doesn't change behavior.
> 
> Signed-off-by: Martin Wilck <mwilck@suse.com>
> ---
>   block/genhd.c         | 15 ++++++++++-----
>   drivers/scsi/sd.c     |  3 ++-
>   drivers/scsi/sr.c     |  3 ++-
>   include/linux/genhd.h |  7 +++++++
>   4 files changed, 21 insertions(+), 7 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
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