powerpc/perf/hv-24x7: Define add_event_to_24x7_request()

Move code that maps a perf_event to a 24x7 request buffer into a
separate function, add_event_to_24x7_request().

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index e78b1272aa0e248c41c0deb9e748a82d7c72f73a..fe74221a35ffbb535a3921cba19b5349e12bc9ab 100644 (file)
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -1000,15 +1000,52 @@ static void log_24x7_hcall(struct hv_24x7_request_buffer *request_buffer,
                        result_buffer->failing_request_ix);
 }
 
-static unsigned long single_24x7_request(struct perf_event *event, u64 *count)
+/*
+ * Add the given @event to the next slot in the 24x7 request_buffer.
+ *
+ * Note that H_GET_24X7_DATA hcall allows reading several counters'
+ * values in a single HCALL. We expect the caller to add events to the
+ * request buffer one by one, make the HCALL and process the results.
+ */
+static int add_event_to_24x7_request(struct perf_event *event,
+                               struct hv_24x7_request_buffer *request_buffer)
 {
        u16 idx;
+       int i;
+       struct hv_24x7_request *req;
+
+       if (request_buffer->num_requests > 254) {
+               pr_devel("Too many requests for 24x7 HCALL %d\n",
+                               request_buffer->num_requests);
+               return -EINVAL;
+       }
+
+       if (is_physical_domain(event_get_domain(event)))
+               idx = event_get_core(event);
+       else
+               idx = event_get_vcpu(event);
+
+       i = request_buffer->num_requests++;
+       req = &request_buffer->requests[i];
+
+       req->performance_domain = event_get_domain(event);
+       req->data_size = cpu_to_be16(8);
+       req->data_offset = cpu_to_be32(event_get_offset(event));
+       req->starting_lpar_ix = cpu_to_be16(event_get_lpar(event)),
+       req->max_num_lpars = cpu_to_be16(1);
+       req->starting_ix = cpu_to_be16(idx);
+       req->max_ix = cpu_to_be16(1);
+
+       return 0;
+}
+
+static unsigned long single_24x7_request(struct perf_event *event, u64 *count)
+{
        unsigned long ret;
 
        struct hv_24x7_request_buffer *request_buffer;
        struct hv_24x7_data_result_buffer *result_buffer;
        struct hv_24x7_result *resb;
-       struct hv_24x7_request *req;
 
        BUILD_BUG_ON(sizeof(*request_buffer) > 4096);
        BUILD_BUG_ON(sizeof(*result_buffer) > 4096);
@@ -1019,23 +1056,11 @@ static unsigned long single_24x7_request(struct perf_event *event, u64 *count)
        memset(request_buffer, 0, 4096);
        memset(result_buffer, 0, 4096);
 
-       if (is_physical_domain(event_get_domain(event)))
-               idx = event_get_core(event);
-       else
-               idx = event_get_vcpu(event);
-
        request_buffer->interface_version = HV_24X7_IF_VERSION_CURRENT;
-       request_buffer->num_requests = 1;
-
-       req = &request_buffer->requests[0];
 
-       req->performance_domain = event_get_domain(event);
-       req->data_size = cpu_to_be16(8);
-       req->data_offset = cpu_to_be32(event_get_offset(event));
-       req->starting_lpar_ix = cpu_to_be16(event_get_lpar(event)),
-       req->max_num_lpars = cpu_to_be16(1);
-       req->starting_ix = cpu_to_be16(idx);
-       req->max_ix = cpu_to_be16(1);
+       ret = add_event_to_24x7_request(event, request_buffer);
+       if (ret)
+               return ret;
 
        /*
         * NOTE: Due to variable number of array elements in request and