In some cases initial bind of scm memory for an lpar can fail if
previously it wasn't released using a scm-unbind hcall. This situation
can arise due to panic of the previous kernel or forced lpar reset. In
such cases the H_SCM_BIND_MEM return a H_OVERLAP error.
To mitigate such cases the patch updates drc_pmem_bind() to force a
call to drc_pmem_unbind() in case the initial bind of scm memory fails
with H_OVERLAP error. In case scm-bind operation again fails after the
forced scm-unbind then we follow the existing error path.
Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com>
---
arch/powerpc/platforms/pseries/papr_scm.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
b/arch/powerpc/platforms/pseries/papr_scm.c
index d790e4e4ffb3..049d7927c0a4 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -44,19 +44,26 @@ struct papr_scm_priv {
struct nd_interleave_set nd_set;
};
+/* Forward declaration */
+static int drc_pmem_unbind(struct papr_scm_priv *);
+
static int drc_pmem_bind(struct papr_scm_priv *p)
{
unsigned long ret[PLPAR_HCALL_BUFSIZE];
uint64_t rc, token;
- uint64_t saved = 0;
+ uint64_t saved;
+ bool tried_unbind = false;
+ dev_dbg(&p->pdev->dev, "bind drc %x\n", p->drc_index);
/*
* When the hypervisor cannot map all the requested memory in a single
* hcall it returns H_BUSY and we call again with the token until
* we get H_SUCCESS. Aborting the retry loop before getting H_SUCCESS
* leave the system in an undefined state, so we wait.
*/
+retry:
token = 0;
+ saved = 0;
do {
rc = plpar_hcall(H_SCM_BIND_MEM, ret, p->drc_index, 0,
@@ -68,8 +75,18 @@ static int drc_pmem_bind(struct papr_scm_priv *p)
} while (rc == H_BUSY);
if (rc) {
- dev_err(&p->pdev->dev, "bind err: %lld\n", rc);
- return -ENXIO;
+ /* retry after unbinding */
+ if (rc == H_OVERLAP && !tried_unbind) {
+ dev_warn(&p->pdev->dev, "Un-binding and retrying\n");
+ /* Try unbind and ignore any errors */
+ tried_unbind = true;
+ drc_pmem_unbind(p);
+ goto retry;
+
+ } else {
+ dev_err(&p->pdev->dev, "bind err: %lld\n", rc);
+ return -ENXIO;
+ }
}
p->bound_addr = saved;
--
2.21.0
