[RFC v5 027/126] misc: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &fatal_err
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and than propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatel, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit (together with its neighbors) was generated by

for f in $(git grep -l errp \*.[ch]); do \
    spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
    --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
done;

then fix a bit of compilation problems: coccinelle for some reason
leaves several
f() {
    ...
    goto out;
    ...
    out:
}
patterns, with "out:" at function end.

then
./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"

(auto-msg was a file with this commit message)

Still, for backporting it may be more comfortable to use only the first
command and then do one huge commit.

Reported-by: Kevin Wolf <address@hidden>
Reported-by: Greg Kurz <address@hidden>
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 hw/misc/ivshmem.c | 37 ++++++++++++++++---------------------
 hw/misc/tmp105.c  |  7 +++----
 hw/misc/tmp421.c  |  7 +++----
 3 files changed, 22 insertions(+), 29 deletions(-)

diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 5e3b05eae0..31292c3f43 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -474,11 +474,11 @@ static void ivshmem_add_kvm_msi_virq(IVShmemState *s, int 
vector,
 
 static void setup_interrupt(IVShmemState *s, int vector, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
     bool with_irqfd = kvm_msi_via_irqfd_enabled() &&
         ivshmem_has_feature(s, IVSHMEM_MSI);
     PCIDevice *pdev = PCI_DEVICE(s);
-    Error *err = NULL;
 
     IVSHMEM_DPRINTF("setting up interrupt for vector: %d\n", vector);
 
@@ -487,9 +487,8 @@ static void setup_interrupt(IVShmemState *s, int vector, 
Error **errp)
         watch_vector_notifier(s, n, vector);
     } else if (msix_enabled(pdev)) {
         IVSHMEM_DPRINTF("with irqfd\n");
-        ivshmem_add_kvm_msi_virq(s, vector, &err);
-        if (err) {
-            error_propagate(errp, err);
+        ivshmem_add_kvm_msi_virq(s, vector, errp);
+        if (*errp) {
             return;
         }
 
@@ -506,7 +505,7 @@ static void setup_interrupt(IVShmemState *s, int vector, 
Error **errp)
 
 static void process_msg_shmem(IVShmemState *s, int fd, Error **errp)
 {
-    Error *local_err = NULL;
+    ERRP_AUTO_PROPAGATE();
     struct stat buf;
     size_t size;
 
@@ -527,9 +526,8 @@ static void process_msg_shmem(IVShmemState *s, int fd, 
Error **errp)
 
     /* mmap the region and map into the BAR2 */
     memory_region_init_ram_from_fd(&s->server_bar2, OBJECT(s),
-                                   "ivshmem.bar2", size, true, fd, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+                                   "ivshmem.bar2", size, true, fd, errp);
+    if (*errp) {
         return;
     }
 
@@ -662,13 +660,12 @@ static int64_t ivshmem_recv_msg(IVShmemState *s, int 
*pfd, Error **errp)
 
 static void ivshmem_recv_setup(IVShmemState *s, Error **errp)
 {
-    Error *err = NULL;
+    ERRP_AUTO_PROPAGATE();
     int64_t msg;
     int fd;
 
-    msg = ivshmem_recv_msg(s, &fd, &err);
-    if (err) {
-        error_propagate(errp, err);
+    msg = ivshmem_recv_msg(s, &fd, errp);
+    if (*errp) {
         return;
     }
     if (msg != IVSHMEM_PROTOCOL_VERSION) {
@@ -694,9 +691,8 @@ static void ivshmem_recv_setup(IVShmemState *s, Error 
**errp)
      * older versions of the device accepted it out of order, but
      * broke when an interrupt setup message arrived before it.
      */
-    msg = ivshmem_recv_msg(s, &fd, &err);
-    if (err) {
-        error_propagate(errp, err);
+    msg = ivshmem_recv_msg(s, &fd, errp);
+    if (*errp) {
         return;
     }
     if (fd != -1 || msg < 0 || msg > IVSHMEM_MAX_PEERS) {
@@ -709,14 +705,12 @@ static void ivshmem_recv_setup(IVShmemState *s, Error 
**errp)
      * Receive more messages until we got shared memory.
      */
     do {
-        msg = ivshmem_recv_msg(s, &fd, &err);
-        if (err) {
-            error_propagate(errp, err);
+        msg = ivshmem_recv_msg(s, &fd, errp);
+        if (*errp) {
             return;
         }
-        process_msg(s, msg, fd, &err);
-        if (err) {
-            error_propagate(errp, err);
+        process_msg(s, msg, fd, errp);
+        if (*errp) {
             return;
         }
     } while (msg != -1);
@@ -864,6 +858,7 @@ static void ivshmem_write_config(PCIDevice *pdev, uint32_t 
address,
 
 static void ivshmem_common_realize(PCIDevice *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     IVShmemState *s = IVSHMEM_COMMON(dev);
     Error *err = NULL;
     uint8_t *pci_conf;
diff --git a/hw/misc/tmp105.c b/hw/misc/tmp105.c
index 75ddad3a12..c603f7024d 100644
--- a/hw/misc/tmp105.c
+++ b/hw/misc/tmp105.c
@@ -71,13 +71,12 @@ static void tmp105_get_temperature(Object *obj, Visitor *v, 
const char *name,
 static void tmp105_set_temperature(Object *obj, Visitor *v, const char *name,
                                    void *opaque, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     TMP105State *s = TMP105(obj);
-    Error *local_err = NULL;
     int64_t temp;
 
-    visit_type_int(v, name, &temp, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_int(v, name, &temp, errp);
+    if (*errp) {
         return;
     }
     if (temp >= 128000 || temp < -128000) {
diff --git a/hw/misc/tmp421.c b/hw/misc/tmp421.c
index 9f044705fa..20f069513c 100644
--- a/hw/misc/tmp421.c
+++ b/hw/misc/tmp421.c
@@ -140,16 +140,15 @@ static void tmp421_get_temperature(Object *obj, Visitor 
*v, const char *name,
 static void tmp421_set_temperature(Object *obj, Visitor *v, const char *name,
                                    void *opaque, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     TMP421State *s = TMP421(obj);
-    Error *local_err = NULL;
     int64_t temp;
     bool ext_range = (s->config[0] & TMP421_CONFIG_RANGE);
     int offset = ext_range * 64 * 256;
     int tempid;
 
-    visit_type_int(v, name, &temp, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_int(v, name, &temp, errp);
+    if (*errp) {
         return;
     }
 
-- 
2.21.0