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| author | Vaibhav Jain <vaibhav@linux.vnet.ibm.com> | 2016-10-14 11:38:36 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-10-19 11:35:39 +0200 |
| commit | 70b565bbdb911023373e035225ab10077e4ab937 (patch) | |
| tree | cc2d84c644b647a89b3ffa26953e4194127a95f4 /drivers/misc/cxl/guest.c | |
| parent | powerpc/boot: Fix boot on systems with uncompressed kernel image (diff) | |
| download | linux-70b565bbdb911023373e035225ab10077e4ab937.tar.xz linux-70b565bbdb911023373e035225ab10077e4ab937.zip | |
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: 62fa19d4b4fd ("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>
Diffstat (limited to 'drivers/misc/cxl/guest.c')
| -rw-r--r-- | drivers/misc/cxl/guest.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c index 9aa58a77a24d..3e102cd6ed91 100644 --- a/drivers/misc/cxl/guest.c +++ b/drivers/misc/cxl/guest.c @@ -1152,6 +1152,9 @@ struct cxl *cxl_guest_init_adapter(struct device_node *np, struct platform_devic if ((rc = cxl_sysfs_adapter_add(adapter))) goto err_put1; + /* release the context lock as the adapter is configured */ + cxl_adapter_context_unlock(adapter); + return adapter; err_put1: |