• Mike Christie's avatar
    [SCSI] fc class: unblock target after calling terminate callback (take 2) · fff9d40c
    Mike Christie authored
    When we block a rport and the driver implements the terminate
    callback we will fail IO that was running quickly. However
    IO that was in the scsi_device/block queue sits there until
    the dev_loss_tmo fires, and this can make it look like IO is
    lost because new IO will get executed but that IO stuck in
    the blocked queue sits there for some time longer.
    With this patch when the fast io fail tmo fires, we will
    fail the blocked IO and any new IO. This patch also allows
    all drivers to partially support the fast io fail tmo. If the
    terminate io callback is not implemented, we will still fail blocked
    IO and any new IO, so multipath can handle that.
    This patch also allows the fc and iscsi classes to implement the
    same behavior. The timers are just unfornately named differently.
    This patch also fixes the problem where drivers were unblocking
    the target in their terminate callback, which was needed for
    rport removal, but for fast io fail timeout it would cause
    IO to bounce arround the scsi/block layer and the LLD queuecommand.
    And it for drivers that could have IO stuck but did not have
    a terminate callback the unblock calls in the class will fix
    - fix up bit setting style to meet JamesS's pref.
    - Broke out new host byte error changes to make it easier to read.
    - added JamesS's ack from list.
    - initial patch
    Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
    Acked-by: default avatarJames Smart <James.Smart@emulex.com>
    Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
scsi_transport_fc.c 99.5 KB