migration/rdma: Fix QEMUFileHooks method return values
The QEMUFileHooks methods don't come with a written contract. Digging
through the code calling them, we find:
* save_page():
Negative values RAM_SAVE_CONTROL_DELAYED and
RAM_SAVE_CONTROL_NOT_SUPP are special. Any other negative value is
an unspecified error.
qemu_rdma_save_page() returns -EIO or rdma->error_state on error. I
believe the latter is always negative. Nothing stops either of them
to clash with the special values, though. Feels unlikely, but fix
it anyway to return only the special values and -1.
* before_ram_iterate(), after_ram_iterate():
Negative value means error. qemu_rdma_registration_start() and
qemu_rdma_registration_stop() comply as far as I can tell. Make
them comply *obviously*, by returning -1 on error.
* hook_ram_load:
Negative value means error. rdma_load_hook() already returns -1 on
error. Leave it alone.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-24-armbru@redhat.com>
diff --git a/migration/rdma.c b/migration/rdma.c
index 55eb822..974edde 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -3268,12 +3268,11 @@
rdma = qatomic_rcu_read(&rioc->rdmaout);
if (!rdma) {
- return -EIO;
+ return -1;
}
- ret = check_error_state(rdma);
- if (ret) {
- return ret;
+ if (check_error_state(rdma)) {
+ return -1;
}
qemu_fflush(f);
@@ -3329,9 +3328,10 @@
}
return RAM_SAVE_CONTROL_DELAYED;
+
err:
rdma->error_state = ret;
- return ret;
+ return -1;
}
static void rdma_accept_incoming_migration(void *opaque);
@@ -3577,12 +3577,11 @@
rdma = qatomic_rcu_read(&rioc->rdmain);
if (!rdma) {
- return -EIO;
+ return -1;
}
- ret = check_error_state(rdma);
- if (ret) {
- return ret;
+ if (check_error_state(rdma)) {
+ return -1;
}
local = &rdma->local_ram_blocks;
@@ -3615,7 +3614,7 @@
(unsigned int)comp->block_idx,
rdma->local_ram_blocks.nb_blocks);
ret = -EIO;
- goto out;
+ goto err;
}
block = &(rdma->local_ram_blocks.block[comp->block_idx]);
@@ -3627,7 +3626,7 @@
case RDMA_CONTROL_REGISTER_FINISHED:
trace_qemu_rdma_registration_handle_finished();
- goto out;
+ return 0;
case RDMA_CONTROL_RAM_BLOCKS_REQUEST:
trace_qemu_rdma_registration_handle_ram_blocks();
@@ -3648,7 +3647,7 @@
if (ret) {
error_report("rdma migration: error dest "
"registering ram blocks");
- goto out;
+ goto err;
}
}
@@ -3687,7 +3686,7 @@
if (ret < 0) {
error_report("rdma migration: error sending remote info");
- goto out;
+ goto err;
}
break;
@@ -3714,7 +3713,7 @@
(unsigned int)reg->current_index,
rdma->local_ram_blocks.nb_blocks);
ret = -ENOENT;
- goto out;
+ goto err;
}
block = &(rdma->local_ram_blocks.block[reg->current_index]);
if (block->is_ram_block) {
@@ -3724,7 +3723,7 @@
block->block_name, block->offset,
reg->key.current_addr);
ret = -ERANGE;
- goto out;
+ goto err;
}
host_addr = (block->local_host_addr +
(reg->key.current_addr - block->offset));
@@ -3740,7 +3739,7 @@
" chunk: %" PRIx64,
block->block_name, reg->key.chunk);
ret = -ERANGE;
- goto out;
+ goto err;
}
}
chunk_start = ram_chunk_start(block, chunk);
@@ -3752,7 +3751,7 @@
chunk, chunk_start, chunk_end)) {
error_report("cannot get rkey");
ret = -EINVAL;
- goto out;
+ goto err;
}
reg_result->rkey = tmp_rkey;
@@ -3769,7 +3768,7 @@
if (ret < 0) {
error_report("Failed to send control buffer");
- goto out;
+ goto err;
}
break;
case RDMA_CONTROL_UNREGISTER_REQUEST:
@@ -3792,7 +3791,7 @@
if (ret != 0) {
perror("rdma unregistration chunk failed");
ret = -ret;
- goto out;
+ goto err;
}
rdma->total_registrations--;
@@ -3805,24 +3804,23 @@
if (ret < 0) {
error_report("Failed to send control buffer");
- goto out;
+ goto err;
}
break;
case RDMA_CONTROL_REGISTER_RESULT:
error_report("Invalid RESULT message at dest.");
ret = -EIO;
- goto out;
+ goto err;
default:
error_report("Unknown control message %s", control_desc(head.type));
ret = -EIO;
- goto out;
+ goto err;
}
} while (1);
-out:
- if (ret < 0) {
- rdma->error_state = ret;
- }
- return ret;
+
+err:
+ rdma->error_state = ret;
+ return -1;
}
/* Destination:
@@ -3844,7 +3842,7 @@
rdma = qatomic_rcu_read(&rioc->rdmain);
if (!rdma) {
- return -EIO;
+ return -1;
}
/* Find the matching RAMBlock in our local list */
@@ -3857,7 +3855,7 @@
if (found == -1) {
error_report("RAMBlock '%s' not found on destination", name);
- return -ENOENT;
+ return -1;
}
rdma->local_ram_blocks.block[curr].src_index = rdma->next_src_index;
@@ -3887,7 +3885,6 @@
{
QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(qemu_file_get_ioc(f));
RDMAContext *rdma;
- int ret;
if (migration_in_postcopy()) {
return 0;
@@ -3896,12 +3893,11 @@
RCU_READ_LOCK_GUARD();
rdma = qatomic_rcu_read(&rioc->rdmaout);
if (!rdma) {
- return -EIO;
+ return -1;
}
- ret = check_error_state(rdma);
- if (ret) {
- return ret;
+ if (check_error_state(rdma)) {
+ return -1;
}
trace_qemu_rdma_registration_start(flags);
@@ -3930,12 +3926,11 @@
RCU_READ_LOCK_GUARD();
rdma = qatomic_rcu_read(&rioc->rdmaout);
if (!rdma) {
- return -EIO;
+ return -1;
}
- ret = check_error_state(rdma);
- if (ret) {
- return ret;
+ if (check_error_state(rdma)) {
+ return -1;
}
qemu_fflush(f);
@@ -3966,7 +3961,7 @@
qemu_rdma_reg_whole_ram_blocks : NULL);
if (ret < 0) {
fprintf(stderr, "receiving remote info!");
- return ret;
+ return -1;
}
nb_dest_blocks = resp.len / sizeof(RDMADestBlock);
@@ -3989,7 +3984,7 @@
"not identical on both the source and destination.",
local->nb_blocks, nb_dest_blocks);
rdma->error_state = -EINVAL;
- return -EINVAL;
+ return -1;
}
qemu_rdma_move_header(rdma, reg_result_idx, &resp);
@@ -4005,7 +4000,7 @@
local->block[i].length,
rdma->dest_blocks[i].length);
rdma->error_state = -EINVAL;
- return -EINVAL;
+ return -1;
}
local->block[i].remote_host_addr =
rdma->dest_blocks[i].remote_host_addr;
@@ -4025,7 +4020,7 @@
return 0;
err:
rdma->error_state = ret;
- return ret;
+ return -1;
}
static const QEMUFileHooks rdma_read_hooks = {
