From 0110c6b86a828c9c2f42fbed4fc0da30ad7bf6eb Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Thu, 28 Sep 2023 15:19:49 +0200 Subject: [PATCH] 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 Reviewed-by: Li Zhijian Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela Message-ID: <20230928132019.2544702-24-armbru@redhat.com> --- migration/rdma.c | 79 +++++++++++++++++++++++------------------------- 1 file changed, 37 insertions(+), 42 deletions(-) diff --git a/migration/rdma.c b/migration/rdma.c index 55eb8222ea..974edde6a3 100644 --- a/migration/rdma.c +++ b/migration/rdma.c @@ -3268,12 +3268,11 @@ static int qemu_rdma_save_page(QEMUFile *f, ram_addr_t block_offset, 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 @@ static int qemu_rdma_save_page(QEMUFile *f, ram_addr_t block_offset, } 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 @@ static int qemu_rdma_registration_handle(QEMUFile *f) 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 @@ static int qemu_rdma_registration_handle(QEMUFile *f) (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 @@ static int qemu_rdma_registration_handle(QEMUFile *f) 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 @@ static int qemu_rdma_registration_handle(QEMUFile *f) if (ret) { error_report("rdma migration: error dest " "registering ram blocks"); - goto out; + goto err; } } @@ -3687,7 +3686,7 @@ static int qemu_rdma_registration_handle(QEMUFile *f) if (ret < 0) { error_report("rdma migration: error sending remote info"); - goto out; + goto err; } break; @@ -3714,7 +3713,7 @@ static int qemu_rdma_registration_handle(QEMUFile *f) (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 @@ static int qemu_rdma_registration_handle(QEMUFile *f) 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 @@ static int qemu_rdma_registration_handle(QEMUFile *f) " 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 @@ static int qemu_rdma_registration_handle(QEMUFile *f) 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 @@ static int qemu_rdma_registration_handle(QEMUFile *f) if (ret < 0) { error_report("Failed to send control buffer"); - goto out; + goto err; } break; case RDMA_CONTROL_UNREGISTER_REQUEST: @@ -3792,7 +3791,7 @@ static int qemu_rdma_registration_handle(QEMUFile *f) if (ret != 0) { perror("rdma unregistration chunk failed"); ret = -ret; - goto out; + goto err; } rdma->total_registrations--; @@ -3805,24 +3804,23 @@ static int qemu_rdma_registration_handle(QEMUFile *f) 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_block_notification_handle(QEMUFile *f, const char *name) rdma = qatomic_rcu_read(&rioc->rdmain); if (!rdma) { - return -EIO; + return -1; } /* Find the matching RAMBlock in our local list */ @@ -3857,7 +3855,7 @@ rdma_block_notification_handle(QEMUFile *f, const char *name) 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 @@ static int qemu_rdma_registration_start(QEMUFile *f, { QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(qemu_file_get_ioc(f)); RDMAContext *rdma; - int ret; if (migration_in_postcopy()) { return 0; @@ -3896,12 +3893,11 @@ static int qemu_rdma_registration_start(QEMUFile *f, 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 @@ static int qemu_rdma_registration_stop(QEMUFile *f, 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 @@ static int qemu_rdma_registration_stop(QEMUFile *f, 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 @@ static int qemu_rdma_registration_stop(QEMUFile *f, "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 @@ static int qemu_rdma_registration_stop(QEMUFile *f, 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 @@ static int qemu_rdma_registration_stop(QEMUFile *f, return 0; err: rdma->error_state = ret; - return ret; + return -1; } static const QEMUFileHooks rdma_read_hooks = { -- 2.39.5