[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH] xen-blkfront: don't make discard-alignment mandatory
On Tue, Jan 19, 2021 at 11:11:26AM +0100, Jürgen Groß wrote: > On 19.01.21 11:06, Roger Pau Monné wrote: > > On Tue, Jan 19, 2021 at 08:43:01AM +0100, Jürgen Groß wrote: > > > On 18.01.21 16:15, Roger Pau Monne wrote: > > > > Don't require the discard-alignment xenstore node to be present in > > > > order to correctly setup the feature. This can happen with versions of > > > > QEMU that only write the discard-granularity but not the > > > > discard-alignment node. > > > > > > > > Assume discard-alignment is 0 if not present. While there also fix the > > > > logic to not enable the discard feature if discard-granularity is not > > > > present. > > > > > > > > Reported-by: Arthur Borsboom <arthurborsboom@xxxxxxxxx> > > > > Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> > > > > --- > > > > Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> > > > > Cc: Juergen Gross <jgross@xxxxxxxx> > > > > Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx> > > > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > > > > Cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx> > > > > Cc: Jens Axboe <axboe@xxxxxxxxx> > > > > Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx > > > > Cc: linux-block@xxxxxxxxxxxxxxx > > > > Cc: Arthur Borsboom <arthurborsboom@xxxxxxxxx> > > > > --- > > > > drivers/block/xen-blkfront.c | 25 +++++++++++++------------ > > > > 1 file changed, 13 insertions(+), 12 deletions(-) > > > > > > > > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > > > > index 5265975b3fba..5a93f7cc2939 100644 > > > > --- a/drivers/block/xen-blkfront.c > > > > +++ b/drivers/block/xen-blkfront.c > > > > @@ -2179,22 +2179,23 @@ static void blkfront_closing(struct > > > > blkfront_info *info) > > > > static void blkfront_setup_discard(struct blkfront_info *info) > > > > { > > > > - int err; > > > > - unsigned int discard_granularity; > > > > - unsigned int discard_alignment; > > > > + unsigned int discard_granularity = 0; > > > > + unsigned int discard_alignment = 0; > > > > + unsigned int discard_secure = 0; > > > > - info->feature_discard = 1; > > > > - err = xenbus_gather(XBT_NIL, info->xbdev->otherend, > > > > + xenbus_gather(XBT_NIL, info->xbdev->otherend, > > > > "discard-granularity", "%u", &discard_granularity, > > > > "discard-alignment", "%u", &discard_alignment, > > > > + "discard-secure", "%u", &discard_secure, > > > > NULL); > > > > > > This would mean that "discard-secure" will be evaluated only if the > > > other two items are set in Xenstore. From blkif.h I can't see this is > > > required, and your patch is modifying today's behavior in this regard. > > > > > > You might want to have three xenbus_read_unsigned() calls instead. > > > > You are right, discard-secure should be fetched regardless of whether > > discard-alignment exists. > > > > I can fetch discard-granularity and discard-alignment using > > xenbus_gather and keep discard-secure using xenbus_read_unsigned. Let > > me send a new version. > > I'm still not convinced this is correct. blkif.h doesn't mention that > discard-alignment will be valid only with discard-granularity being > present. No, in fact I think I need to rework this a little further. Just having feature-discard = 1 should enable the discard functionality, by setting discard-granularity = physical block size and discard-alignment = 0. Roger.
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |