[PATCH 1/3] powerpc/pseries: Simplify check for suspendability during suspend/migration

[Tyrel Datwyler]

During suspend/migration operation we must wait for the VASI state reported
by the hypervisor to become Suspending prior to making the ibm,suspend-me
RTAS call. Calling routines to rtas_ibm_supend_me() pass a vasi_state variable
that exposes the VASI state to the caller. This is unnecessary as the caller
only really cares about the following three conditions; if there is an error
we should bailout, success indicating we have suspended and woken back up so
proceed to device tree updated, or we are not suspendable yet so try calling
rtas_ibm_suspend_me again shortly.

This patch removes the extraneous vasi_state variable and simply uses the
return code to communicate how to proceed. We either succeed, fail, or get
-EAGAIN in which case we sleep for a second before trying to call
rtas_ibm_suspend_me again.

Signed-off-by: Tyrel Datwyler <tyreld at linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/rtas.h           |  2 +-
 arch/powerpc/kernel/rtas.c                | 15 +++++++--------
 arch/powerpc/platforms/pseries/mobility.c |  8 +++-----
 3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index 2e23e92..fc85eb0 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -327,7 +327,7 @@ extern int rtas_suspend_cpu(struct rtas_suspend_me_data *data);
 extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data);
 extern int rtas_online_cpus_mask(cpumask_var_t cpus);
 extern int rtas_offline_cpus_mask(cpumask_var_t cpus);
-extern int rtas_ibm_suspend_me(u64 handle, int *vasi_return);
+extern int rtas_ibm_suspend_me(u64 handle);
 
 struct rtc_time;
 extern unsigned long rtas_get_boot_time(void);
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 21c45a2..603b928 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -897,7 +897,7 @@ int rtas_offline_cpus_mask(cpumask_var_t cpus)
 }
 EXPORT_SYMBOL(rtas_offline_cpus_mask);
 
-int rtas_ibm_suspend_me(u64 handle, int *vasi_return)
+int rtas_ibm_suspend_me(u64 handle)
 {
 	long state;
 	long rc;
@@ -919,13 +919,11 @@ int rtas_ibm_suspend_me(u64 handle, int *vasi_return)
 		printk(KERN_ERR "rtas_ibm_suspend_me: vasi_state returned %ld\n",rc);
 		return rc;
 	} else if (state == H_VASI_ENABLED) {
-		*vasi_return = RTAS_NOT_SUSPENDABLE;
-		return 0;
+		return -EAGAIN;
 	} else if (state != H_VASI_SUSPENDING) {
 		printk(KERN_ERR "rtas_ibm_suspend_me: vasi_state returned state %ld\n",
 		       state);
-		*vasi_return = -1;
-		return 0;
+		return -EIO;
 	}
 
 	if (!alloc_cpumask_var(&offline_mask, GFP_TEMPORARY))
@@ -1060,9 +1058,10 @@ asmlinkage int ppc_rtas(struct rtas_args __user *uargs)
 		int vasi_rc = 0;
 		u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32)
 		              | be32_to_cpu(args.args[1]);
-		rc = rtas_ibm_suspend_me(handle, &vasi_rc);
-		args.rets[0] = cpu_to_be32(vasi_rc);
-		if (rc)
+		rc = rtas_ibm_suspend_me(handle);
+		if (rc == -EAGAIN)
+			args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE);
+		else if (rc)
 			return rc;
 		goto copy_return;
 	}
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 90cf3dc..29e4f04 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -325,15 +325,13 @@ static ssize_t migrate_store(struct class *class, struct class_attribute *attr,
 		return rc;
 
 	do {
-		rc = rtas_ibm_suspend_me(streamid, &vasi_rc);
-		if (!rc && vasi_rc == RTAS_NOT_SUSPENDABLE)
+		rc = rtas_ibm_suspend_me(streamid);
+		if (rc == -EAGAIN)
 			ssleep(1);
-	} while (!rc && vasi_rc == RTAS_NOT_SUSPENDABLE);
+	} while (rc == -EAGAIN);
 
 	if (rc)
 		return rc;
-	if (vasi_rc)
-		return vasi_rc;
 
 	post_mobility_fixup();
 	return count;
-- 
1.7.12.2