OpenCloudOS-Kernel/drivers/misc/cxl
Vaibhav Jain 70b565bbdb cxl: Prevent adapter reset if an active context exists
This patch prevents resetting the cxl adapter via sysfs in presence of
one or more active cxl_context on it. This protects against an
unrecoverable error caused by PSL owning a dirty cache line even after
reset and host tries to touch the same cache line. In case a force reset
of the card is required irrespective of any active contexts, the int
value -1 can be stored in the 'reset' sysfs attribute of the card.

The patch introduces a new atomic_t member named contexts_num inside
struct cxl that holds the number of active context attached to the card
, which is checked against '0' before proceeding with the reset. To
prevent against a race condition where a context is activated just after
reset check is performed, the contexts_num is atomically set to '-1'
after reset-check to indicate that no more contexts can be activated on
the card anymore.

Before activating a context we atomically test if contexts_num is
non-negative and if so, increment its value by one. In case the value of
contexts_num is negative then it indicates that the card is about to be
reset and context activation is error-ed out at that point.

Fixes: 62fa19d4b4 ("cxl: Add ability to reset the card")
Cc: stable@vger.kernel.org # v4.0+
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-10-19 20:35:39 +11:00
..
Kconfig cxl: remove dead Kconfig options 2016-07-19 20:12:29 +10:00
Makefile cxl: Allow a default context to be associated with an external pci_dev 2016-07-14 20:26:52 +10:00
api.c cxl: Prevent adapter reset if an active context exists 2016-10-19 20:35:39 +11:00
base.c cxl: Add support for interrupts on the Mellanox CX4 2016-07-14 20:27:08 +10:00
context.c cxl: Prevent adapter reset if an active context exists 2016-10-19 20:35:39 +11:00
cxl.h cxl: Prevent adapter reset if an active context exists 2016-10-19 20:35:39 +11:00
debugfs.c cxl: Abstract the differences between the PSL and XSL 2016-06-16 23:08:54 +10:00
fault.c powerpc/mm: Replace _PAGE_USER with _PAGE_PRIVILEGED 2016-05-01 18:32:26 +10:00
file.c cxl: Prevent adapter reset if an active context exists 2016-10-19 20:35:39 +11:00
flash.c cxl: static-ify variables to fix sparse warnings 2016-06-16 22:49:27 +10:00
guest.c cxl: Prevent adapter reset if an active context exists 2016-10-19 20:35:39 +11:00
hcalls.c cxl: Add tracepoints around the cxl hcall 2016-03-09 23:40:01 +11:00
hcalls.h cxl: Add guest-specific code 2016-03-09 23:36:52 +11:00
irq.c cxl: Refine slice error debug messages 2016-07-08 22:22:03 +10:00
main.c cxl: Prevent adapter reset if an active context exists 2016-10-19 20:35:39 +11:00
native.c cxl: Flush PSL cache before resetting the adapter 2016-10-04 16:16:42 +11:00
of.c cxl: replace loop with for_each_child_of_node(), remove unneeded of_node_put() 2016-10-04 16:19:23 +11:00
pci.c cxl: Prevent adapter reset if an active context exists 2016-10-19 20:35:39 +11:00
phb.c cxl: Allow a default context to be associated with an external pci_dev 2016-07-14 20:26:52 +10:00
sysfs.c cxl: Prevent adapter reset if an active context exists 2016-10-19 20:35:39 +11:00
trace.c cxl: Add tracepoints 2015-01-22 17:31:51 +11:00
trace.h cxl: Add tracepoints around the cxl hcall 2016-03-09 23:40:01 +11:00
vphb.c cxl: use pcibios_free_controller_deferred() when removing vPHBs 2016-08-22 11:09:33 +10:00