nvme-fc: correct csn initialization and increments on error
authorJames Smart <jsmart2021@gmail.com>
Mon, 8 Apr 2019 18:15:19 +0000 (11:15 -0700)
committerChristoph Hellwig <hch@lst.de>
Thu, 11 Apr 2019 15:28:30 +0000 (17:28 +0200)
commit67f471b6ed3b09033c4ac77ea03f92afdb1989fe
tree19f2e0412e291eb83411fd57775cf879689e2ba0
parenta3761c3c91209b58b6f33bf69dd8bb8ec0c9d925
nvme-fc: correct csn initialization and increments on error

This patch fixes a long-standing bug that initialized the FC-NVME
cmnd iu CSN value to 1. Early FC-NVME specs had the connection starting
with CSN=1. By the time the spec reached approval, the language had
changed to state a connection should start with CSN=0.  This patch
corrects the initialization value for FC-NVME connections.

Additionally, in reviewing the transport, the CSN value is assigned to
the new IU early in the start routine. It's possible that a later dma
map request may fail, causing the command to never be sent to the
controller.  Change the location of the assignment so that it is
immediately prior to calling the lldd. Add a comment block to explain
the impacts if the lldd were to additionally fail sending the command.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
drivers/nvme/host/fc.c