error: Eliminate error_propagate() with Coccinelle, part 1

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.  Convert

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

to

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

where nothing else needs @err.  Coccinelle script:

    @rule1 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
         if (
    (
    -        fun(args, &err, args2)
    +        fun(args, errp, args2)
    |
    -        !fun(args, &err, args2)
    +        !fun(args, errp, args2)
    |
    -        fun(args, &err, args2) op c1
    +        fun(args, errp, args2) op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    )
         }

    @rule2 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    expression var;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
    -    var = fun(args, &err, args2);
    +    var = fun(args, errp, args2);
         ... when != err
         if (
    (
             var
    |
             !var
    |
             var op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    |
             return var;
    )
         }

    @depends on rule1 || rule2@
    identifier err;
    @@
    -    Error *err = NULL;
         ... when != err

Not exactly elegant, I'm afraid.

The "when != lbl:" is necessary to avoid transforming

         if (fun(args, &err)) {
             goto out
         }
         ...
     out:
         error_propagate(errp, err);

even though other paths to label out still need the error_propagate().
For an actual example, see sclp_realize().

Without the "when strict", Coccinelle transforms vfio_msix_setup(),
incorrectly.  I don't know what exactly "when strict" does, only that
it helps here.

The match of return is narrower than what I want, but I can't figure
out how to express "return where the operand doesn't use @err".  For
an example where it's too narrow, see vfio_intx_enable().

Silently fails to convert hw/arm/armsse.c, because Coccinelle gets
confused by ARMSSE being used both as typedef and function-like macro
there.  Converted manually.

Line breaks tidied up manually.  One nested declaration of @local_err
deleted manually.  Preexisting unwanted blank line dropped in
hw/riscv/sifive_e.c.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-35-armbru@redhat.com>

accel/kvm/kvm-all.c

@@ -3113,11 +3113,9 @@ static void kvm_set_kvm_shadow_mem(Object *obj, Visitor *v,
                                    Error **errp)
 {
     KVMState *s = KVM_STATE(obj);
-    Error *error = NULL;
     int64_t value;
 
-    if (!visit_type_int(v, name, &value, &error)) {
-        error_propagate(errp, error);
+    if (!visit_type_int(v, name, &value, errp)) {
         return;
     }
 

accel/tcg/tcg-all.c

@@ -182,11 +182,9 @@ static void tcg_set_tb_size(Object *obj, Visitor *v,
                             Error **errp)
 {
     TCGState *s = TCG_STATE(obj);
-    Error *error = NULL;
     uint32_t value;
 
-    if (!visit_type_uint32(v, name, &value, &error)) {
-        error_propagate(errp, error);
+    if (!visit_type_uint32(v, name, &value, errp)) {
         return;
     }
 

backends/cryptodev-vhost-user.c

@@ -209,8 +209,7 @@ static void cryptodev_vhost_user_init(
         backend->conf.peers.ccs[i] = cc;
 
         if (i == 0) {
-            if (!qemu_chr_fe_init(&s->chr, chr, &local_err)) {
-                error_propagate(errp, local_err);
+            if (!qemu_chr_fe_init(&s->chr, chr, errp)) {
                 return;
             }
         }

backends/cryptodev.c

@@ -154,11 +154,9 @@ cryptodev_backend_set_queues(Object *obj, Visitor *v, const char *name,
                              void *opaque, Error **errp)
 {
     CryptoDevBackend *backend = CRYPTODEV_BACKEND(obj);
-    Error *local_err = NULL;
     uint32_t value;
 
-    if (!visit_type_uint32(v, name, &value, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_uint32(v, name, &value, errp)) {
         return;
     }
     if (!value) {

backends/hostmem-file.c

@@ -110,7 +110,6 @@ static void file_memory_backend_set_align(Object *o, Visitor *v,
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(o);
     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
-    Error *local_err = NULL;
     uint64_t val;
 
     if (host_memory_backend_mr_inited(backend)) {
@@ -119,8 +118,7 @@ static void file_memory_backend_set_align(Object *o, Visitor *v,
         return;
     }
 
-    if (!visit_type_size(v, name, &val, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_size(v, name, &val, errp)) {
         return;
     }
     fb->align = val;

backends/hostmem-memfd.c

@@ -77,7 +77,6 @@ memfd_backend_set_hugetlbsize(Object *obj, Visitor *v, const char *name,
                               void *opaque, Error **errp)
 {
     HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj);
-    Error *local_err = NULL;
     uint64_t value;
 
     if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj))) {
@@ -85,8 +84,7 @@ memfd_backend_set_hugetlbsize(Object *obj, Visitor *v, const char *name,
         return;
     }
 
-    if (!visit_type_size(v, name, &value, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_size(v, name, &value, errp)) {
         return;
     }
     if (!value) {

backends/hostmem.c

@@ -54,7 +54,6 @@ host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
                              void *opaque, Error **errp)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    Error *local_err = NULL;
     uint64_t value;
 
     if (host_memory_backend_mr_inited(backend)) {
@@ -63,8 +62,7 @@ host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
         return;
     }
 
-    if (!visit_type_size(v, name, &value, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_size(v, name, &value, errp)) {
         return;
     }
     if (!value) {
@@ -252,11 +250,9 @@ static void host_memory_backend_set_prealloc_threads(Object *obj, Visitor *v,
     const char *name, void *opaque, Error **errp)
 {
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    Error *local_err = NULL;
     uint32_t value;
 
-    if (!visit_type_uint32(v, name, &value, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_uint32(v, name, &value, errp)) {
         return;
     }
     if (value <= 0) {

backends/tpm/tpm_util.c

@@ -48,7 +48,6 @@ static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
                     Error **errp)
 {
     DeviceState *dev = DEVICE(obj);
-    Error *local_err = NULL;
     Property *prop = opaque;
     TPMBackend *s, **be = qdev_get_prop_ptr(dev, prop);
     char *str;
@@ -58,8 +57,7 @@ static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
         return;
     }
 
-    if (!visit_type_str(v, name, &str, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_str(v, name, &str, errp)) {
         return;
     }
 

block.c

@@ -5663,10 +5663,9 @@ static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs,
     if (bs->open_flags & BDRV_O_INACTIVE) {
         bs->open_flags &= ~BDRV_O_INACTIVE;
         bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
-        ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, &local_err);
+        ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, errp);
         if (ret < 0) {
             bs->open_flags |= BDRV_O_INACTIVE;
-            error_propagate(errp, local_err);
             return;
         }
         bdrv_set_perm(bs, perm, shared_perm);

block/curl.c

@@ -669,7 +669,6 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVCURLState *s = bs->opaque;
     CURLState *state = NULL;
     QemuOpts *opts;
-    Error *local_err = NULL;
     const char *file;
     const char *cookie;
     const char *cookie_secret;
@@ -695,8 +694,7 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags,
 
     qemu_mutex_init(&s->mutex);
     opts = qemu_opts_create(&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)) {
         goto out_noclean;
     }
 

block/file-posix.c

@@ -3331,7 +3331,6 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
                      Error **errp)
 {
     BDRVRawState *s = bs->opaque;
-    Error *local_err = NULL;
     int ret;
 
 #if defined(__APPLE__) && defined(__MACH__)
@@ -3396,9 +3395,8 @@ hdev_open_Mac_error:
 
     s->type = FTYPE_FILE;
 
-    ret = raw_open_common(bs, options, flags, 0, true, &local_err);
+    ret = raw_open_common(bs, options, flags, 0, true, errp);
     if (ret < 0) {
-        error_propagate(errp, local_err);
 #if defined(__APPLE__) && defined(__MACH__)
         if (*bsd_path) {
             filename = bsd_path;
@@ -3674,14 +3672,12 @@ static int cdrom_open(BlockDriverState *bs, QDict *options, int flags,
                       Error **errp)
 {
     BDRVRawState *s = bs->opaque;
-    Error *local_err = NULL;
     int ret;
 
     s->type = FTYPE_CD;
 
-    ret = raw_open_common(bs, options, flags, 0, true, &local_err);
+    ret = raw_open_common(bs, options, flags, 0, true, errp);
     if (ret) {
-        error_propagate(errp, local_err);
         return ret;
     }
 

block/parallels.c

@@ -646,9 +646,8 @@ static int coroutine_fn parallels_co_create_opts(BlockDriver *drv,
     }
 
     /* Create and open the file (protocol layer) */
-    ret = bdrv_create_file(filename, opts, &local_err);
+    ret = bdrv_create_file(filename, opts, errp);
     if (ret < 0) {
-        error_propagate(errp, local_err);
         goto done;
     }
 

block/qcow.c

@@ -973,9 +973,8 @@ static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,
     }
 
     /* Create and open the file (protocol layer) */
-    ret = bdrv_create_file(filename, opts, &local_err);
+    ret = bdrv_create_file(filename, opts, errp);
     if (ret < 0) {
-        error_propagate(errp, local_err);
         goto fail;
     }
 

block/qed.c

@@ -749,9 +749,8 @@ static int coroutine_fn bdrv_qed_co_create_opts(BlockDriver *drv,
     }
 
     /* Create and open the file (protocol layer) */
-    ret = bdrv_create_file(filename, opts, &local_err);
+    ret = bdrv_create_file(filename, opts, errp);
     if (ret < 0) {
-        error_propagate(errp, local_err);
         goto fail;
     }
 

block/throttle-groups.c

@@ -811,7 +811,6 @@ static void throttle_group_set(Object *obj, Visitor *v, const char * name,
     ThrottleGroup *tg = THROTTLE_GROUP(obj);
     ThrottleConfig *cfg;
     ThrottleParamInfo *info = opaque;
-    Error *local_err = NULL;
     int64_t value;
 
     /* If we have finished initialization, don't accept individual property
@@ -823,8 +822,7 @@ static void throttle_group_set(Object *obj, Visitor *v, const char * name,
         return;
     }
 
-    if (!visit_type_int64(v, name, &value, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_int64(v, name, &value, errp)) {
         return;
     }
     if (value < 0) {

block/vhdx.c

@@ -2083,9 +2083,8 @@ static int coroutine_fn vhdx_co_create_opts(BlockDriver *drv,
     }
 
     /* Create and open the file (protocol layer) */
-    ret = bdrv_create_file(filename, opts, &local_err);
+    ret = bdrv_create_file(filename, opts, errp);
     if (ret < 0) {
-        error_propagate(errp, local_err);
         goto fail;
     }
 

block/vmdk.c

@@ -2252,9 +2252,8 @@ static int vmdk_create_extent(const char *filename, int64_t filesize,
     BlockBackend *blk = NULL;
     Error *local_err = NULL;
 
-    ret = bdrv_create_file(filename, opts, &local_err);
+    ret = bdrv_create_file(filename, opts, errp);
     if (ret < 0) {
-        error_propagate(errp, local_err);
         goto exit;
     }
 

block/vpc.c

@@ -1113,9 +1113,8 @@ static int coroutine_fn vpc_co_create_opts(BlockDriver *drv,
     }
 
     /* Create and open the file (protocol layer) */
-    ret = bdrv_create_file(filename, opts, &local_err);
+    ret = bdrv_create_file(filename, opts, errp);
     if (ret < 0) {
-        error_propagate(errp, local_err);
         goto fail;
     }
 

blockdev.c

@@ -509,8 +509,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
         goto err_no_opts;
     }
 
-    if (!qemu_opts_absorb_qdict(opts, bs_opts, &error)) {
-        error_propagate(errp, error);
+    if (!qemu_opts_absorb_qdict(opts, bs_opts, errp)) {
         goto early_err;
     }
 
@@ -827,8 +826,7 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type,
 
     for (i = 0; i < ARRAY_SIZE(opt_renames); i++) {
         if (!qemu_opt_rename(all_opts, opt_renames[i].from,
-                             opt_renames[i].to, &local_err)) {
-            error_propagate(errp, local_err);
+                             opt_renames[i].to, errp)) {
             return NULL;
         }
     }

hw/arm/allwinner-a10.c

@@ -72,15 +72,12 @@ static void aw_a10_realize(DeviceState *dev, Error **errp)
 {
     AwA10State *s = AW_A10(dev);
     SysBusDevice *sysbusdev;
-    Error *err = NULL;
 
-    if (!qdev_realize(DEVICE(&s->cpu), NULL, &err)) {
-        error_propagate(errp, err);
+    if (!qdev_realize(DEVICE(&s->cpu), NULL, errp)) {
         return;
     }
 
-    if (!sysbus_realize(SYS_BUS_DEVICE(&s->intc), &err)) {
-        error_propagate(errp, err);
+    if (!sysbus_realize(SYS_BUS_DEVICE(&s->intc), errp)) {
         return;
     }
     sysbusdev = SYS_BUS_DEVICE(&s->intc);
@@ -91,8 +88,7 @@ static void aw_a10_realize(DeviceState *dev, Error **errp)
                        qdev_get_gpio_in(DEVICE(&s->cpu), ARM_CPU_FIQ));
     qdev_pass_gpios(DEVICE(&s->intc), dev, NULL);
 
-    if (!sysbus_realize(SYS_BUS_DEVICE(&s->timer), &err)) {
-        error_propagate(errp, err);
+    if (!sysbus_realize(SYS_BUS_DEVICE(&s->timer), errp)) {
         return;
     }
     sysbusdev = SYS_BUS_DEVICE(&s->timer);
@@ -114,16 +110,14 @@ static void aw_a10_realize(DeviceState *dev, Error **errp)
         qemu_check_nic_model(&nd_table[0], TYPE_AW_EMAC);
         qdev_set_nic_properties(DEVICE(&s->emac), &nd_table[0]);
     }
-    if (!sysbus_realize(SYS_BUS_DEVICE(&s->emac), &err)) {
-        error_propagate(errp, err);
+    if (!sysbus_realize(SYS_BUS_DEVICE(&s->emac), errp)) {
         return;
     }
     sysbusdev = SYS_BUS_DEVICE(&s->emac);
     sysbus_mmio_map(sysbusdev, 0, AW_A10_EMAC_BASE);
     sysbus_connect_irq(sysbusdev, 0, qdev_get_gpio_in(dev, 55));
 
-    if (!sysbus_realize(SYS_BUS_DEVICE(&s->sata), &err)) {
-        error_propagate(errp, err);
+    if (!sysbus_realize(SYS_BUS_DEVICE(&s->sata), errp)) {
         return;
     }
     sysbus_mmio_map(SYS_BUS_DEVICE(&s->sata), 0, AW_A10_SATA_BASE);