On Wed, Feb 20 2019 at 10:08am -0500,
Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote:
>
>
> On Tue, 19 Feb 2019, Mike Snitzer wrote:
>
> > noclone_endio() must call the target's ->endio method if it exists.
> > Also must handle the various DM_ENDIO_* returns that are possible.
> >
> > Factor out dm_bio_pushback_needed() for both dec_pending() and
> > noclone_endio() to use when handling BLK_STS_DM_REQUEUE.
> >
> > Lastly, there is no need to conditionally set md->immutable_target in
> > __bind(). If the device only uses a single immutable target then it
> > should always be reflected in md->immutable_target. This is important
> > because noclone_endio() benefits from this to get access to the
> > multipath dm_target without needing to add another member to the
> > 'dm_noclone' structure.
> >
> > Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
> > ---
> > drivers/md/dm.c | 77 ++++++++++++++++++++++++++++++++++++++++-----------------
> > 1 file changed, 55 insertions(+), 22 deletions(-)
> >
> > diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> > index 8ff0ced278d7..2299f946c175 100644
> > --- a/drivers/md/dm.c
> > +++ b/drivers/md/dm.c
> > @@ -897,6 +897,28 @@ static int __noflush_suspending(struct mapped_device *md)
> > return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
> > }
> >
> > +static bool dm_bio_pushback_needed(struct mapped_device *md,
> > + struct bio *bio, blk_status_t *error)
> > +{
> > + unsigned long flags;
> > +
> > + /*
> > + * Target requested pushing back the I/O.
> > + */
> > + if (__noflush_suspending(md)) {
> > + spin_lock_irqsave(&md->deferred_lock, flags);
> > + // FIXME: using bio_list_add_head() creates LIFO
> > + bio_list_add_head(&md->deferred, bio);
> > + spin_unlock_irqrestore(&md->deferred_lock, flags);
> > + return true;
> > + } else {
> > + /* noflush suspend was interrupted. */
> > + *error = BLK_STS_IOERR;
> > + }
> > +
> > + return false;
> > +}
> > +
> > /*
> > * Decrements the number of outstanding ios that a bio has been
> > * cloned into, completing the original io if necc.
> > @@ -917,19 +939,8 @@ static void dec_pending(struct dm_io *io, blk_status_t error)
> > }
> >
> > if (atomic_dec_and_test(&io->io_count)) {
> > - if (io->status == BLK_STS_DM_REQUEUE) {
> > - /*
> > - * Target requested pushing back the I/O.
> > - */
> > - spin_lock_irqsave(&md->deferred_lock, flags);
> > - if (__noflush_suspending(md))
> > - /* NOTE early return due to BLK_STS_DM_REQUEUE below */
> > - bio_list_add_head(&md->deferred, io->orig_bio);
> > - else
> > - /* noflush suspend was interrupted. */
> > - io->status = BLK_STS_IOERR;
> > - spin_unlock_irqrestore(&md->deferred_lock, flags);
> > - }
> > + if (unlikely(io->status == BLK_STS_DM_REQUEUE))
> > + (void) dm_bio_pushback_needed(md, bio, &io->status);
>
> This triggers compiler warning because the variable bio is uninitialized
> here.
Right, I fixed it up in latest git, please see latest 'dm-5.1' branch:
https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-5.1
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
