9pfs: Use g_new() & friends where that makes obvious sense

g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
for two reasons.  One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.

This commit only touches allocations with size arguments of the form
sizeof(T).

Initial patch created mechanically with:

    $ spatch --in-place --sp-file scripts/coccinelle/use-g_new-etc.cocci \
	     --macro-file scripts/cocci-macro-file.h FILES...

This uncovers a typing error:

    ../hw/9pfs/9p.c: In function ‘qid_path_fullmap’:
    ../hw/9pfs/9p.c:855:13: error: assignment to ‘QpfEntry *’ from incompatible pointer type ‘QppEntry *’ [-Werror=incompatible-pointer-types]
      855 |         val = g_new0(QppEntry, 1);
	  |             ^

Harmless, because QppEntry is larger than QpfEntry.  Manually fixed to
allocate a QpfEntry instead.

Cc: Greg Kurz <groug@kaod.org>
Cc: Christian Schoenebeck <qemu_oss@crudebyte.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20220315144156.1595462-3-armbru@redhat.com>

hw/9pfs/9p-proxy.c

@@ -1187,7 +1187,7 @@ static int proxy_parse_opts(QemuOpts *opts, FsDriverEntry *fs, Error **errp)
 
 static int proxy_init(FsContext *ctx, Error **errp)
 {
-    V9fsProxy *proxy = g_malloc(sizeof(V9fsProxy));
+    V9fsProxy *proxy = g_new(V9fsProxy, 1);
     int sock_id;
 
     if (ctx->export_flags & V9FS_PROXY_SOCK_NAME) {

hw/9pfs/9p-synth.c

@@ -49,7 +49,7 @@ static V9fsSynthNode *v9fs_add_dir_node(V9fsSynthNode *parent, int mode,
 
     /* Add directory type and remove write bits */
     mode = ((mode & 0777) | S_IFDIR) & ~(S_IWUSR | S_IWGRP | S_IWOTH);
-    node = g_malloc0(sizeof(V9fsSynthNode));
+    node = g_new0(V9fsSynthNode, 1);
     if (attr) {
         /* We are adding .. or . entries */
         node->attr = attr;
@@ -128,7 +128,7 @@ int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode,
     }
     /* Add file type and remove write bits */
     mode = ((mode & 0777) | S_IFREG);
-    node = g_malloc0(sizeof(V9fsSynthNode));
+    node = g_new0(V9fsSynthNode, 1);
     node->attr         = &node->actual_attr;
     node->attr->inode  = synth_node_count++;
     node->attr->nlink  = 1;

hw/9pfs/9p.c

@@ -324,7 +324,7 @@ static V9fsFidState *alloc_fid(V9fsState *s, int32_t fid)
             return NULL;
         }
     }
-    f = g_malloc0(sizeof(V9fsFidState));
+    f = g_new0(V9fsFidState, 1);
     f->fid = fid;
     f->fid_type = P9_FID_NONE;
     f->ref = 1;
@@ -804,7 +804,7 @@ static int qid_inode_prefix_hash_bits(V9fsPDU *pdu, dev_t dev)
 
     val = qht_lookup(&pdu->s->qpd_table, &lookup, hash);
     if (!val) {
-        val = g_malloc0(sizeof(QpdEntry));
+        val = g_new0(QpdEntry, 1);
         *val = lookup;
         affix = affixForIndex(pdu->s->qp_affix_next);
         val->prefix_bits = affix.bits;
@@ -852,7 +852,7 @@ static int qid_path_fullmap(V9fsPDU *pdu, const struct stat *stbuf,
             return -ENFILE;
         }
 
-        val = g_malloc0(sizeof(QppEntry));
+        val = g_new0(QpfEntry, 1);
         *val = lookup;
 
         /* new unique inode and device combo */
@@ -928,7 +928,7 @@ static int qid_path_suffixmap(V9fsPDU *pdu, const struct stat *stbuf,
             return -ENFILE;
         }
 
-        val = g_malloc0(sizeof(QppEntry));
+        val = g_new0(QppEntry, 1);
         *val = lookup;
 
         /* new unique inode affix and device combo */

hw/9pfs/codir.c

@@ -141,9 +141,9 @@ static int do_readdir_many(V9fsPDU *pdu, V9fsFidState *fidp,
 
         /* append next node to result chain */
         if (!e) {
-            *entries = e = g_malloc0(sizeof(V9fsDirEnt));
+            *entries = e = g_new0(V9fsDirEnt, 1);
         } else {
-            e = e->next = g_malloc0(sizeof(V9fsDirEnt));
+            e = e->next = g_new0(V9fsDirEnt, 1);
         }
         e->dent = qemu_dirent_dup(dent);
 
@@ -163,7 +163,7 @@ static int do_readdir_many(V9fsPDU *pdu, V9fsFidState *fidp,
                 break;
             }
 
-            e->st = g_malloc0(sizeof(struct stat));
+            e->st = g_new0(struct stat, 1);
             memcpy(e->st, &stbuf, sizeof(struct stat));
         }
 

tests/qtest/virtio-9p-test.c

@@ -468,12 +468,12 @@ static void v9fs_rreaddir(P9Req *req, uint32_t *count, uint32_t *nentries,
          togo -= 13 + 8 + 1 + 2 + slen, ++n)
     {
         if (!e) {
-            e = g_malloc(sizeof(struct V9fsDirent));
+            e = g_new(struct V9fsDirent, 1);
             if (entries) {
                 *entries = e;
             }
         } else {
-            e = e->next = g_malloc(sizeof(struct V9fsDirent));
+            e = e->next = g_new(struct V9fsDirent, 1);
         }
         e->next = NULL;
         /* qid[13] offset[8] type[1] name[s] */