Commit 595ab641 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

migration: handle EAGAIN while reading QEMUFile 



This will never happen right now (the assertion would fail).  The
next patch will set the socket or pipe in non-blocking mode, thus
enabling this part of the code.

Coroutines can just stop whenever they want with qemu_coroutine_yield.
As soon as select tells the main loop that the migration stream is
readable, the coroutine is re-entered directly in qemu_get_buffer,
where it will read more data and pass it to the loading routines.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1c12e1f5

savevm.c

+24 −6
Original line number Diff line number Diff line
@@ -200,13 +200,22 @@ static int socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size) 
    QEMUFileSocket *s = opaque;

    ssize_t len;



    do {

    for (;;) {

        len = qemu_recv(s->fd, buf, size, 0);

    } while (len == -1 && socket_error() == EINTR);

        if (len != -1) {

            break;

        }

        if (socket_error() == EAGAIN) {

            assert(qemu_in_coroutine());

            qemu_coroutine_yield();

        } else if (socket_error() != EINTR) {

            break;

        }

    }



    if (len == -1)

    if (len == -1) {

        len = -socket_error();



    }

    return len;

}
@@ -237,10 +246,19 @@ static int stdio_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size) 
    FILE *fp = s->stdio_file;

    int bytes;



    do {

    for (;;) {

        clearerr(fp);

        bytes = fread(buf, 1, size, fp);

    } while ((bytes == 0) && ferror(fp) && (errno == EINTR));

        if (bytes != 0 || !ferror(fp)) {

            break;

        }

        if (errno == EAGAIN) {

            assert(qemu_in_coroutine());

            qemu_coroutine_yield();

        } else if (errno != EINTR) {

            break;

        }

    }

    return bytes;

}