Re: [PATCH] sys/block: Add discard_support entry

[Greg KH <greg@kroah.com>]

On Mon, May 02, 2011 at 01:25:04PM +0200, Lukas Czerner wrote:
> Currently there is no convenient way how to get the information from
> userspace whether or not the block device supports discard other
> than try to call BLKDISCARD ioctl and check the result, which is not
> really good way to do it.
> 
> We already have BLKDISCARDZEROES ioctl and
> /sys/block/sda/queue/discard_zeroes_data to tell whether  subsequent
> reads after discard returns all zeroes. This commit adds at least sysfs
> interface /sys/block/sda/queue/discard_support to tell whether device
> support discard.
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> Cc: Jens Axboe <jaxboe@fusionio.com>
> Cc: Jeff Moyer <jmoyer@redhat.com>
> ---
>  block/blk-sysfs.c |   11 +++++++++++

If you ever change/add/remove a sysfs file, you also need a
Documentation/ABI/ entry.  Please include that in the next revision of
this patch, if you do one.

thanks,

greg k-h