Prasad Pandit <[email protected]> writes:
> On Fri, 9 Jan 2026 at 18:12, Fabiano Rosas <[email protected]> wrote:
>>
>> Centralize, on both sides of migration, the setting of the to_src_file
>> and from_dst_file QEMUFiles. This will clean up the interface with
>> channel.c and rdma.c, allowing those files to stop dealing with
>> QEMUFile themselves.
>>
>> (multifd_recv_new_channel was changed to return bool+errp for
>> convenience)
>>
>> Reviewed-by: Peter Xu <[email protected]>
>> Signed-off-by: Fabiano Rosas <[email protected]>
>> ---
>> migration/channel.c | 9 +----
>> migration/migration.c | 84 ++++++++++++++++++++++++++-----------------
>> migration/migration.h | 2 ++
>> migration/multifd.c | 8 +++--
>> migration/multifd.h | 2 +-
>> 5 files changed, 61 insertions(+), 44 deletions(-)
>>
>> diff --git a/migration/channel.c b/migration/channel.c
>> index 26cb7bf059..6acce7b2a2 100644
>> --- a/migration/channel.c
>> +++ b/migration/channel.c
>> @@ -14,7 +14,6 @@
>> #include "channel.h"
>> #include "tls.h"
>> #include "migration.h"
>> -#include "qemu-file.h"
>> #include "trace.h"
>> #include "qapi/error.h"
>> #include "io/channel-tls.h"
>> @@ -80,14 +79,8 @@ void migration_channel_connect(MigrationState *s,
>> QIOChannel *ioc)
>> return;
>> }
>>
>> - QEMUFile *f = qemu_file_new_output(ioc);
>> -
>> migration_ioc_register_yank(ioc);
>> -
>> - qemu_mutex_lock(&s->qemu_file_lock);
>> - s->to_dst_file = f;
>> - qemu_mutex_unlock(&s->qemu_file_lock);
>> -
>> + migration_outgoing_setup(ioc);
>> migration_connect(s);
>> }
>>
>> diff --git a/migration/migration.c b/migration/migration.c
>> index 1ea6125454..b7367eb5cf 100644
>> --- a/migration/migration.c
>> +++ b/migration/migration.c
>> @@ -930,17 +930,56 @@ out:
>> migrate_incoming_unref_outgoing_state();
>> }
>>
>> -/**
>> - * migration_incoming_setup: Setup incoming migration
>> - * @f: file for main migration channel
>> +static bool migration_has_main_and_multifd_channels(void);
>> +
>> +/*
>> + * Returns whether all the necessary channels to proceed with the
>> + * incoming migration have been established without error.
>> */
>> -static void migration_incoming_setup(QEMUFile *f)
>> +bool migration_incoming_setup(QIOChannel *ioc, uint8_t channel, Error
>> **errp)
>> {
>> MigrationIncomingState *mis = migration_incoming_get_current();
>> + QEMUFile *f;
>>
>> - assert(!mis->from_src_file);
>> - mis->from_src_file = f;
>> - qemu_file_set_blocking(f, false, &error_abort);
>> + if (multifd_recv_setup(errp) != 0) {
>> + return false;
>> + }
>> +
>> + switch (channel) {
>> + case CH_MAIN:
>> + f = qemu_file_new_input(ioc);
>> + assert(!mis->from_src_file);
>> + mis->from_src_file = f;
>> + qemu_file_set_blocking(f, false, &error_abort);
>> + break;
>> +
>> + case CH_MULTIFD:
>> + if (!multifd_recv_new_channel(ioc, errp)) {
>> + return false;
>> + }
>> + break;
>> +
>> + case CH_POSTCOPY:
>> + assert(!mis->postcopy_qemufile_dst);
>> + f = qemu_file_new_input(ioc);
>> + postcopy_preempt_new_channel(mis, f);
>> + return false;
>> +
>> + default:
>> + g_assert_not_reached();
>> + }
>> +
>> + return migration_has_main_and_multifd_channels();
>> +}
>> +
>> +void migration_outgoing_setup(QIOChannel *ioc)
>> +{
>> + MigrationState *s = migrate_get_current();
>> + QEMUFile *f = qemu_file_new_output(ioc);
>> +
>> + qemu_mutex_lock(&s->qemu_file_lock);
>> + s->to_dst_file = f;
>> + qemu_mutex_unlock(&s->qemu_file_lock);
>> }
>
> * Shouldn't migration_outgoing_setup() also return bool, to be
> consistent with migration_incoming_setup() above? OR make
> migration_incoming_setup() return void.
>
That would be a change simply to make the signatures consistent. It's
not indicative (granted, as it usually is) of a consistency in
design. The reason migration_incoming_setup() returns bool is to follow
the recommendation of returning whether errp is set. Here, there's no
errp, so no need.
(before multifd_send_setup moved to the migration thread, maybe we could
still make both functions more analogous, but I'm not sure how much
benefit that would have brought)
>> /* Returns true if recovered from a paused migration, otherwise false */
>> @@ -988,7 +1027,11 @@ void migration_incoming_process(void)
>>
>> void migration_fd_process_incoming(QEMUFile *f)
>> {
>> - migration_incoming_setup(f);
>> + MigrationIncomingState *mis = migration_incoming_get_current();
>> +
>> + assert(!mis->from_src_file);
>> + mis->from_src_file = f;
>> + qemu_file_set_blocking(f, false, &error_abort);
>> migration_incoming_process();
>> }
>
> * Is it possible to move above mis->from_src_file = f part to
> migration_incoming_setup()?
>
Yes, patch 14.
>
>> @@ -1011,8 +1054,6 @@ static bool
>> migration_has_main_and_multifd_channels(void)
>> void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
>> {
>> MigrationIncomingState *mis = migration_incoming_get_current();
>> - Error *local_err = NULL;
>> - QEMUFile *f;
>> uint8_t channel;
>> uint32_t channel_magic = 0;
>> int ret = 0;
>> @@ -1066,28 +1107,7 @@ void migration_ioc_process_incoming(QIOChannel *ioc,
>> Error **errp)
>> channel = CH_POSTCOPY;
>> }
>>
>> - if (multifd_recv_setup(errp) != 0) {
>> - return;
>> - }
>> -
>> - if (channel == CH_MAIN) {
>> - f = qemu_file_new_input(ioc);
>> - migration_incoming_setup(f);
>> - } else if (channel == CH_MULTIFD) {
>> - /* Multiple connections */
>> - multifd_recv_new_channel(ioc, &local_err);
>> - if (local_err) {
>> - error_propagate(errp, local_err);
>> - return;
>> - }
>> - } else if (channel == CH_POSTCOPY) {
>> - assert(!mis->postcopy_qemufile_dst);
>> - f = qemu_file_new_input(ioc);
>> - postcopy_preempt_new_channel(mis, f);
>> - return;
>> - }
>> -
>> - if (migration_has_main_and_multifd_channels()) {
>> + if (migration_incoming_setup(ioc, channel, errp)) {
>> migration_incoming_process();
>> }
>> }
>> diff --git a/migration/migration.h b/migration/migration.h
>> index d134881eaf..4dcf299719 100644
>> --- a/migration/migration.h
>> +++ b/migration/migration.h
>> @@ -530,6 +530,8 @@ void migrate_set_state(MigrationStatus *state,
>> MigrationStatus old_state,
>> void migration_fd_process_incoming(QEMUFile *f);
>> void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp);
>> void migration_incoming_process(void);
>> +bool migration_incoming_setup(QIOChannel *ioc, uint8_t channel, Error
>> **errp);
>> +void migration_outgoing_setup(QIOChannel *ioc);
>>
>> bool migration_has_all_channels(void);
>>
>> diff --git a/migration/multifd.c b/migration/multifd.c
>> index 3fb1a07ba9..4980ed4f04 100644
>> --- a/migration/multifd.c
>> +++ b/migration/multifd.c
>> @@ -1521,7 +1521,7 @@ bool multifd_recv_all_channels_created(void)
>> * Try to receive all multifd channels to get ready for the migration.
>> * Sets @errp when failing to receive the current channel.
>> */
>> -void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
>> +bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
>> {
>> MultiFDRecvParams *p;
>> Error *local_err = NULL;
>> @@ -1536,7 +1536,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error
>> **errp)
>> "failed to receive packet"
>> " via multifd channel %d: ",
>>
>> qatomic_read(&multifd_recv_state->count));
>> - return;
>> + return false;
>> }
>> trace_multifd_recv_new_channel(id);
>> } else {
>> @@ -1549,7 +1549,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error
>> **errp)
>> id);
>> multifd_recv_terminate_threads(error_copy(local_err));
>> error_propagate(errp, local_err);
>> - return;
>> + return false;
>> }
>> p->c = ioc;
>> object_ref(OBJECT(ioc));
>> @@ -1558,4 +1558,6 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error
>> **errp)
>> qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
>> QEMU_THREAD_JOINABLE);
>> qatomic_inc(&multifd_recv_state->count);
>> +
>> + return true;
>> }
>> diff --git a/migration/multifd.h b/migration/multifd.h
>> index 9b6d81e7ed..89a395aef2 100644
>> --- a/migration/multifd.h
>> +++ b/migration/multifd.h
>> @@ -42,7 +42,7 @@ int multifd_recv_setup(Error **errp);
>> void multifd_recv_cleanup(void);
>> void multifd_recv_shutdown(void);
>> bool multifd_recv_all_channels_created(void);
>> -void multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
>> +bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
>> void multifd_recv_sync_main(void);
>> int multifd_send_sync_main(MultiFDSyncReq req);
>> bool multifd_queue_page(RAMBlock *block, ram_addr_t offset);
>> --
>
> * Change looks okay.
> Reviewed-by: Prasad Pandit <[email protected]>
>
> Thank you.
> ---
> - Prasad
