error: Eliminate error_propagate() with Coccinelle, part 2

When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.  The previous commit did that with a Coccinelle script I
consider fairly trustworthy.  This commit uses the same script with
the matching of return taken out, i.e. we convert

    if (!foo(..., &err)) {
        ...
        error_propagate(errp, err);
        ...
    }

to

    if (!foo(..., errp)) {
        ...
        ...
    }

This is unsound: @err could still be read between afterwards.  I don't
know how to express "no read of @err without an intervening write" in
Coccinelle.  Instead, I manually double-checked for uses of @err.

Suboptimal line breaks tweaked manually.  qdev_realize() simplified
further to placate scripts/checkpatch.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-36-armbru@redhat.com>

1 files changed, 4 insertions, 9 deletions

diff --git a/block/qcow2.c b/block/qcow2.c
index ce6333fd1e..f419860e67 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -990,8 +990,7 @@ static int qcow2_update_options_prepare(BlockDriverState *bs,
     encryptfmt = qdict_get_try_str(encryptopts, "format");
 
     opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort);
-    if (!qemu_opts_absorb_qdict(opts, options, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qemu_opts_absorb_qdict(opts, options, errp)) {
         ret = -EINVAL;
         goto fail;
     }
@@ -1595,8 +1594,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
 
     /* read qcow2 extensions */
     if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL,
-                              flags, &update_header, &local_err)) {
-        error_propagate(errp, local_err);
+                              flags, &update_header, errp)) {
         ret = -EINVAL;
         goto fail;
     }
@@ -3357,7 +3355,6 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
     int version;
     int refcount_order;
     uint64_t* refcount_table;
-    Error *local_err = NULL;
     int ret;
     uint8_t compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
 
@@ -3583,9 +3580,8 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
     }
     blk = blk_new_open(NULL, NULL, options,
                        BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH,
-                       &local_err);
+                       errp);
     if (blk == NULL) {
-        error_propagate(errp, local_err);
         ret = -EIO;
         goto out;
     }
@@ -3665,9 +3661,8 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
     }
     blk = blk_new_open(NULL, NULL, options,
                        BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO,
-                       &local_err);
+                       errp);
     if (blk == NULL) {
-        error_propagate(errp, local_err);
         ret = -EIO;
         goto out;
     }