[PATCH v20210616 21/36] tools: restore: move map_errs array

[Olaf Hering <olaf@xxxxxxxxx>]

Remove allocation from hotpath, move map_errs array into preallocated space.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
---
 tools/libs/saverestore/common.h  |  1 +
 tools/libs/saverestore/restore.c | 12 +-----------
 2 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/tools/libs/saverestore/common.h b/tools/libs/saverestore/common.h
index 54352f5427..34042c2b90 100644
--- a/tools/libs/saverestore/common.h
+++ b/tools/libs/saverestore/common.h
@@ -241,6 +241,7 @@ struct sr_restore_arrays {
     uint32_t types[MAX_BATCH_SIZE];
     /* process_page_data */
     xen_pfn_t mfns[MAX_BATCH_SIZE];
+    int map_errs[MAX_BATCH_SIZE];
 };
 
 struct xc_sr_context
diff --git a/tools/libs/saverestore/restore.c b/tools/libs/saverestore/restore.c
index 1a7cfbcd47..6eb955423c 100644
--- a/tools/libs/saverestore/restore.c
+++ b/tools/libs/saverestore/restore.c
@@ -206,21 +206,13 @@ static int process_page_data(struct xc_sr_context *ctx, 
unsigned int count,
 {
     xc_interface *xch = ctx->xch;
     xen_pfn_t *mfns = ctx->restore.m->mfns;
-    int *map_errs = malloc(count * sizeof(*map_errs));
+    int *map_errs = ctx->restore.m->map_errs;
     int rc;
     void *mapping = NULL, *guest_page = NULL;
     unsigned int i, /* i indexes the pfns from the record. */
         j,          /* j indexes the subset of pfns we decide to map. */
         nr_pages = 0;
 
-    if ( !map_errs )
-    {
-        rc = -1;
-        ERROR("Failed to allocate %zu bytes to process page data",
-              count * (sizeof(*mfns) + sizeof(*map_errs)));
-        goto err;
-    }
-
     rc = populate_pfns(ctx, count, pfns, types);
     if ( rc )
     {
@@ -298,8 +290,6 @@ static int process_page_data(struct xc_sr_context *ctx, 
unsigned int count,
     if ( mapping )
         xenforeignmemory_unmap(xch->fmem, mapping, nr_pages);
 
-    free(map_errs);
-
     return rc;
 }