powerpc/pseries: Migration code reorganization / hibernation prep

Partition hibernation will use some of the same code as is
currently used for Live Partition Migration. This function
further abstracts this code such that code outside of rtas.c
can utilize it. It also changes the error field in the suspend
me data structure to be an atomic type, since it is set and
checked on different cpus without any barriers or locking.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 70 insertions, 35 deletions

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 0e1ec6f746f6..41cfde0ca11b 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -47,14 +47,6 @@ struct rtas_t rtas = {
 };
 EXPORT_SYMBOL(rtas);
 
-struct rtas_suspend_me_data {
-        atomic_t working; /* number of cpus accessing this struct */
-        atomic_t done;
-        int token; /* ibm,suspend-me */
-        int error;
-        struct completion *complete; /* wait on this until working == 0 */
-};
-
 DEFINE_SPINLOCK(rtas_data_buf_lock);
 EXPORT_SYMBOL(rtas_data_buf_lock);
 
@@ -714,14 +706,53 @@ void rtas_os_term(char *str)
 
 static int ibm_suspend_me_token = RTAS_UNKNOWN_SERVICE;
 #ifdef CONFIG_PPC_PSERIES
-static void rtas_percpu_suspend_me(void *info)
+static int __rtas_suspend_last_cpu(struct rtas_suspend_me_data *data, int wake_when_done)
+{
+        u16 slb_size = mmu_slb_size;
+        int rc = H_MULTI_THREADS_ACTIVE;
+        int cpu;
+
+        slb_set_size(SLB_MIN_SIZE);
+        printk(KERN_DEBUG "calling ibm,suspend-me on cpu %i\n", smp_processor_id());
+
+        while (rc == H_MULTI_THREADS_ACTIVE && !atomic_read(&data->done) &&
+               !atomic_read(&data->error))
+                rc = rtas_call(data->token, 0, 1, NULL);
+
+        if (rc || atomic_read(&data->error)) {
+                printk(KERN_DEBUG "ibm,suspend-me returned %d\n", rc);
+                slb_set_size(slb_size);
+        }
+
+        if (atomic_read(&data->error))
+                rc = atomic_read(&data->error);
+
+        atomic_set(&data->error, rc);
+
+        if (wake_when_done) {
+                atomic_set(&data->done, 1);
+
+                for_each_online_cpu(cpu)
+                        plpar_hcall_norets(H_PROD, get_hard_smp_processor_id(cpu));
+        }
+
+        if (atomic_dec_return(&data->working) == 0)
+                complete(data->complete);
+
+        return rc;
+}
+
+int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data)
+{
+        atomic_inc(&data->working);
+        return __rtas_suspend_last_cpu(data, 0);
+}
+
+static int __rtas_suspend_cpu(struct rtas_suspend_me_data *data, int wake_when_done)
 {
         long rc = H_SUCCESS;
         unsigned long msr_save;
-        u16 slb_size = mmu_slb_size;
         int cpu;
-        struct rtas_suspend_me_data *data =
-                (struct rtas_suspend_me_data *)info;
 
         atomic_inc(&data->working);
 
@@ -729,7 +760,7 @@ static void rtas_percpu_suspend_me(void *info)
         msr_save = mfmsr();
         mtmsr(msr_save & ~(MSR_EE));
 
-        while (rc == H_SUCCESS && !atomic_read(&data->done))
+        while (rc == H_SUCCESS && !atomic_read(&data->done) && !atomic_read(&data->error))
                 rc = plpar_hcall_norets(H_JOIN);
 
         mtmsr(msr_save);
@@ -741,33 +772,37 @@ static void rtas_percpu_suspend_me(void *info)
                 /* All other cpus are in H_JOIN, this cpu does
                  * the suspend.
                  */
-                slb_set_size(SLB_MIN_SIZE);
-                printk(KERN_DEBUG "calling ibm,suspend-me on cpu %i\n",
-                       smp_processor_id());
-                data->error = rtas_call(data->token, 0, 1, NULL);
-
-                if (data->error) {
-                        printk(KERN_DEBUG "ibm,suspend-me returned %d\n",
-                               data->error);
-                        slb_set_size(slb_size);
-                }
+                return __rtas_suspend_last_cpu(data, wake_when_done);
         } else {
                 printk(KERN_ERR "H_JOIN on cpu %i failed with rc = %ld\n",
                        smp_processor_id(), rc);
-                data->error = rc;
+                atomic_set(&data->error, rc);
         }
 
-        atomic_set(&data->done, 1);
+        if (wake_when_done) {
+                atomic_set(&data->done, 1);
 
-        /* This cpu did the suspend or got an error; in either case,
-         * we need to prod all other other cpus out of join state.
-         * Extra prods are harmless.
-         */
-        for_each_online_cpu(cpu)
-                plpar_hcall_norets(H_PROD, get_hard_smp_processor_id(cpu));
+                /* This cpu did the suspend or got an error; in either case,
+                 * we need to prod all other other cpus out of join state.
+                 * Extra prods are harmless.
+                 */
+                for_each_online_cpu(cpu)
+                        plpar_hcall_norets(H_PROD, get_hard_smp_processor_id(cpu));
+        }
 out:
         if (atomic_dec_return(&data->working) == 0)
                 complete(data->complete);
+        return rc;
+}
+
+int rtas_suspend_cpu(struct rtas_suspend_me_data *data)
+{
+        return __rtas_suspend_cpu(data, 0);
+}
+
+static void rtas_percpu_suspend_me(void *info)
+{
+        __rtas_suspend_cpu((struct rtas_suspend_me_data *)info, 1);
 }
 
 static int rtas_ibm_suspend_me(struct rtas_args *args)
@@ -802,22 +837,22 @@ static int rtas_ibm_suspend_me(struct rtas_args *args)
 
         atomic_set(&data.working, 0);
         atomic_set(&data.done, 0);
+        atomic_set(&data.error, 0);
         data.token = rtas_token("ibm,suspend-me");
-        data.error = 0;
         data.complete = &done;
 
         /* Call function on all CPUs.  One of us will make the
          * rtas call
          */
         if (on_each_cpu(rtas_percpu_suspend_me, &data, 0))
-                data.error = -EINVAL;
+                atomic_set(&data.error, -EINVAL);
 
         wait_for_completion(&done);
 
-        if (data.error != 0)
+        if (atomic_read(&data.error) != 0)
                 printk(KERN_ERR "Error doing global join\n");
 
-        return data.error;
+        return atomic_read(&data.error);
 }
 #else /* CONFIG_PPC_PSERIES */
 static int rtas_ibm_suspend_me(struct rtas_args *args)