From: Maciej S. Szmigiero Date: Tue, 4 Mar 2025 22:03:39 +0000 (+0100) Subject: migration/multifd: Make multifd_send() thread safe X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d19cc4dca0b21af95fee36a2ddad34eb4bd6b67f;p=qemu.git migration/multifd: Make multifd_send() thread safe 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 Signed-off-by: Maciej S. Szmigiero Link: https://lore.kernel.org/qemu-devel/dd0f3bcc02ca96a7d523ca58ea69e495a33b453b.1741124640.git.maciej.szmigiero@oracle.com Signed-off-by: Cédric Le Goater --- diff --git a/migration/multifd.c b/migration/multifd.c index 01f427d8ed..add6f86175 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -50,6 +50,10 @@ typedef struct { struct { MultiFDSendParams *params; + + /* multifd_send() body is not thread safe, needs serialization */ + QemuMutex multifd_send_mutex; + /* * Global number of generated multifd packets. * @@ -339,6 +343,8 @@ bool multifd_send(MultiFDSendData **send_data) return false; } + QEMU_LOCK_GUARD(&multifd_send_state->multifd_send_mutex); + /* We wait here, until at least one channel is ready */ qemu_sem_wait(&multifd_send_state->channels_ready); @@ -507,6 +513,7 @@ static void multifd_send_cleanup_state(void) socket_cleanup_outgoing_migration(); qemu_sem_destroy(&multifd_send_state->channels_created); qemu_sem_destroy(&multifd_send_state->channels_ready); + qemu_mutex_destroy(&multifd_send_state->multifd_send_mutex); g_free(multifd_send_state->params); multifd_send_state->params = NULL; g_free(multifd_send_state); @@ -887,6 +894,7 @@ bool multifd_send_setup(void) thread_count = migrate_multifd_channels(); multifd_send_state = g_malloc0(sizeof(*multifd_send_state)); 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_ready, 0); qatomic_set(&multifd_send_state->exiting, 0);