Re: [PATCH 12/29] powerpc/pseries/mobility: extract VASI session polling logic
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2020-12-04 12:57:12
Nathan Lynch [off-list ref] writes:
quoted hunk ↗ jump to hunk
The behavior of rtas_ibm_suspend_me_unsafe() is to return -EAGAIN to the caller until the specified VASI suspend session state makes the transition from H_VASI_ENABLED to H_VASI_SUSPENDING. In the interest of separating concerns to prepare for a new implementation of the join/suspend sequence, extract VASI session polling logic into a couple of local functions. Waiting for the session state to reach H_VASI_SUSPENDING before calling rtas_ibm_suspend_me_unsafe() ensures that we will never get an EAGAIN result necessitating a retry. No user-visible change in behavior is intended. Signed-off-by: Nathan Lynch <redacted> --- arch/powerpc/platforms/pseries/mobility.c | 76 +++++++++++++++++++++-- 1 file changed, 71 insertions(+), 5 deletions(-)diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index dc6abf164db7..1b8ae221b98a 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c@@ -345,6 +345,73 @@ void post_mobility_fixup(void)
...
+
+static int wait_for_vasi_session_suspending(u64 handle)
+{
+ unsigned long state;
+ bool keep_polling;
+ int ret;
+
+ /*
+ * Wait for transition from H_VASI_ENABLED to
+ * H_VASI_SUSPENDING. Treat anything else as an error.
+ */
+ do {
+ keep_polling = false;
+ ret = poll_vasi_state(handle, &state);
+ if (ret != 0)
+ break;
+
+ switch (state) {
+ case H_VASI_SUSPENDING:
+ break;
+ case H_VASI_ENABLED:
+ keep_polling = true;
+ ssleep(1);
+ break;
+ default:
+ pr_err("unexpected H_VASI_STATE result %lu\n", state);
+ ret = -EIO;
+ break;
+ }
+ } while (keep_polling);
This seems like it could be simpler?
eg:
while (true) {
ret = poll_vasi_state(handle, &state);
if (ret != 0 || state == H_VASI_SUSPENDING)
break;
else if (state == H_VASI_ENABLED)
ssleep(1);
else {
pr_err("unexpected H_VASI_STATE result %lu\n", state);
ret = -EIO;
break;
}
}
Or did I miss something?
cheers