This patch eliminates a potential deadlock that is possible when XPC
disconnects a channel to a partition that has gone down. This deadlock will
occur if at least one of the kthreads created by XPC for the purpose of making
callouts to the channel's registerer is detained in the registerer and will
not be returning back to XPC until some registerer request occurs on the now
downed partition. The potential for a deadlock is removed by ensuring that
there always is a kthread available to make the channel disconnecting callout
to the registerer.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Jack Steiner identified a problem where XPC can cause a silent
data corruption. On module load, the placement may cause the
xpc_remote_copy_buffer to span two physical pages. DMA transfers are
done to the start virtual address translated to physical.
This patch changes the buffer from a statically allocated buffer to a
kmalloc'd buffer. Dean Nelson reviewed this before posting. I have
tested it in the configuration that was showing the memory corruption
and verified it works. I also added a BUG_ON statement to help catch
this if a similar situation is encountered.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix some sparse warnings on ia64. Large constants that should be long
instead of int. Use NULL instead of 0. Add some missing __iomem
casts. Replace a non-C99 structure assignment.
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Take advantage of kzalloc() as well as reduce the size of code generated
for the error returns in xpc_setup_infrastructure().
Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix XPC so that it does not deliver any messages until the connected
callout has returned, as well as, prevent the disconnected callout to
occur before the disconnecting callout has returned.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Migrate sn2 code to use mutex and completion events rather than
semaphores.
Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cleanup a few items after moving xpc.h from arch/ia64/sn/kernel to
include/asm-ia64/sn.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Move xpc.h from arch/ia64/sn/kernel to include/asm-ia64/sn without change.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
