powerpc/pseries/dlpar: use RTAS work area API

Hold a work area object for the duration of the RTAS
ibm,configure-connector sequence, eliminating locking and copying
around each RTAS call.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-13-26929c8cce78@linux.ibm.com

diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index 498d6efcb5ae7eb7e12084184d92a848e50730df..9b65b50a545600d7463351441ea37a233e380db1 100644 (file)
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -22,6 +22,7 @@
 #include <asm/machdep.h>
 #include <linux/uaccess.h>
 #include <asm/rtas.h>
+#include <asm/rtas-work-area.h>
 
 static struct workqueue_struct *pseries_hp_wq;
 
@@ -137,6 +138,7 @@ struct device_node *dlpar_configure_connector(__be32 drc_index,
        struct property *property;
        struct property *last_property = NULL;
        struct cc_workarea *ccwa;
+       struct rtas_work_area *work_area;
        char *data_buf;
        int cc_token;
        int rc = -1;
@@ -145,29 +147,18 @@ struct device_node *dlpar_configure_connector(__be32 drc_index,
        if (cc_token == RTAS_UNKNOWN_SERVICE)
                return NULL;
 
-       data_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
-       if (!data_buf)
-               return NULL;
+       work_area = rtas_work_area_alloc(SZ_4K);
+       data_buf = rtas_work_area_raw_buf(work_area);
 
        ccwa = (struct cc_workarea *)&data_buf[0];
        ccwa->drc_index = drc_index;
        ccwa->zero = 0;
 
        do {
-               /* Since we release the rtas_data_buf lock between configure
-                * connector calls we want to re-populate the rtas_data_buffer
-                * with the contents of the previous call.
-                */
-               spin_lock(&rtas_data_buf_lock);
-
-               memcpy(rtas_data_buf, data_buf, RTAS_DATA_BUF_SIZE);
-               rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL);
-               memcpy(data_buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);
-
-               spin_unlock(&rtas_data_buf_lock);
-
-               if (rtas_busy_delay(rc))
-                       continue;
+               do {
+                       rc = rtas_call(cc_token, 2, 1, NULL,
+                                      rtas_work_area_phys(work_area), NULL);
+               } while (rtas_busy_delay(rc));
 
                switch (rc) {
                case COMPLETE:
@@ -227,7 +218,7 @@ struct device_node *dlpar_configure_connector(__be32 drc_index,
        } while (rc);
 
 cc_error:
-       kfree(data_buf);
+       rtas_work_area_free(work_area);
 
        if (rc) {
                if (first_dn)