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migration/multifd: Make multifd_send() thread safe

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multifd_send() function is currently not thread safe, make it thread safe
by holding a lock during its execution.

This way it will be possible to safely call it concurrently from multiple
threads.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/dd0f3bcc02ca96a7d523ca58ea69e495a33b453b.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
Maciej S. Szmigiero 2025-03-04 23:03:39 +01:00 committed by Cédric Le Goater
parent f588f3c46a
commit d19cc4dca0
1 changed files with 8 additions and 0 deletions
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8
migration/multifd.c
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@ -50,6 +50,10 @@ typedef struct {
struct { struct {
MultiFDSendParams *params; MultiFDSendParams *params;
/* multifd_send() body is not thread safe, needs serialization */
QemuMutex multifd_send_mutex;
/* /*
* Global number of generated multifd packets. * Global number of generated multifd packets.
* *
@ -339,6 +343,8 @@ bool multifd_send(MultiFDSendData **send_data)
return false; return false;
} }
QEMU_LOCK_GUARD(&multifd_send_state->multifd_send_mutex);
/* We wait here, until at least one channel is ready */ /* We wait here, until at least one channel is ready */
qemu_sem_wait(&multifd_send_state->channels_ready); qemu_sem_wait(&multifd_send_state->channels_ready);
@ -507,6 +513,7 @@ static void multifd_send_cleanup_state(void)
socket_cleanup_outgoing_migration(); socket_cleanup_outgoing_migration();
qemu_sem_destroy(&multifd_send_state->channels_created); qemu_sem_destroy(&multifd_send_state->channels_created);
qemu_sem_destroy(&multifd_send_state->channels_ready); qemu_sem_destroy(&multifd_send_state->channels_ready);
qemu_mutex_destroy(&multifd_send_state->multifd_send_mutex);
g_free(multifd_send_state->params); g_free(multifd_send_state->params);
multifd_send_state->params = NULL; multifd_send_state->params = NULL;
g_free(multifd_send_state); g_free(multifd_send_state);
@ -887,6 +894,7 @@ bool multifd_send_setup(void)
thread_count = migrate_multifd_channels(); thread_count = migrate_multifd_channels();
multifd_send_state = g_malloc0(sizeof(*multifd_send_state)); multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
multifd_send_state->params = g_new0(MultiFDSendParams, thread_count); multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
qemu_mutex_init(&multifd_send_state->multifd_send_mutex);
qemu_sem_init(&multifd_send_state->channels_created, 0); qemu_sem_init(&multifd_send_state->channels_created, 0);
qemu_sem_init(&multifd_send_state->channels_ready, 0); qemu_sem_init(&multifd_send_state->channels_ready, 0);
qatomic_set(&multifd_send_state->exiting, 0); qatomic_set(&multifd_send_state->exiting, 0);