[RFC v5 104/126] NVMe Block Driver: 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>
---
 block/nvme.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/block/nvme.c b/block/nvme.c
index 5be3a39b63..8447d1caea 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -187,9 +187,9 @@ static NVMeQueuePair 
*nvme_create_queue_pair(BlockDriverState *bs,
                                              int idx, int size,
                                              Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int i, r;
     BDRVNVMeState *s = bs->opaque;
-    Error *local_err = NULL;
     NVMeQueuePair *q = g_new0(NVMeQueuePair, 1);
     uint64_t prp_list_iova;
 
@@ -209,16 +209,14 @@ static NVMeQueuePair 
*nvme_create_queue_pair(BlockDriverState *bs,
         req->prp_list_page = q->prp_list_pages + i * s->page_size;
         req->prp_list_iova = prp_list_iova + i * s->page_size;
     }
-    nvme_init_queue(bs, &q->sq, size, NVME_SQ_ENTRY_BYTES, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    nvme_init_queue(bs, &q->sq, size, NVME_SQ_ENTRY_BYTES, errp);
+    if (*errp) {
         goto fail;
     }
     q->sq.doorbell = &s->regs->doorbells[idx * 2 * s->doorbell_scale];
 
-    nvme_init_queue(bs, &q->cq, size, NVME_CQ_ENTRY_BYTES, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    nvme_init_queue(bs, &q->cq, size, NVME_CQ_ENTRY_BYTES, errp);
+    if (*errp) {
         goto fail;
     }
     q->cq.doorbell = &s->regs->doorbells[(idx * 2 + 1) * s->doorbell_scale];
@@ -569,12 +567,12 @@ static bool nvme_poll_cb(void *opaque)
 static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
                      Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     BDRVNVMeState *s = bs->opaque;
     int ret;
     uint64_t cap;
     uint64_t timeout_ms;
     uint64_t deadline, now;
-    Error *local_err = NULL;
 
     qemu_co_mutex_init(&s->dma_map_lock);
     qemu_co_queue_init(&s->dma_flush_queue);
@@ -666,9 +664,8 @@ static int nvme_init(BlockDriverState *bs, const char 
*device, int namespace,
     aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
                            false, nvme_handle_event, nvme_poll_cb);
 
-    nvme_identify(bs, namespace, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    nvme_identify(bs, namespace, errp);
+    if (*errp) {
         ret = -EIO;
         goto out;
     }
-- 
2.21.0