From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:45713) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOnGf-0000up-3L for qemu-devel@nongnu.org; Thu, 18 Oct 2012 06:24:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TOnGT-0001q2-S7 for qemu-devel@nongnu.org; Thu, 18 Oct 2012 06:23:57 -0400 Received: from mail-pb0-f45.google.com ([209.85.160.45]:47856) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOnGT-0001pn-M6 for qemu-devel@nongnu.org; Thu, 18 Oct 2012 06:23:45 -0400 Received: by mail-pb0-f45.google.com with SMTP id rp2so8296519pbb.4 for ; Thu, 18 Oct 2012 03:23:45 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Thu, 18 Oct 2012 12:22:37 +0200 Message-Id: <1350555758-29988-12-git-send-email-pbonzini@redhat.com> In-Reply-To: <1350555758-29988-1-git-send-email-pbonzini@redhat.com> References: <1350555758-29988-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 11/12] migration: handle EAGAIN while reading QEMUFile List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: quintela@redhat.com 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: Paolo Bonzini --- savevm.c | 30 ++++++++++++++++++++++++------ 1 file modificato, 24 inserzioni(+), 6 rimozioni(-) diff --git a/savevm.c b/savevm.c index ae5e617..783bb3c 100644 --- a/savevm.c +++ b/savevm.c @@ -199,13 +199,22 @@ 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 (errno == EAGAIN) { + assert(qemu_in_coroutine()); + qemu_coroutine_yield(); + } else if (errno != EINTR) { + break; + } + } - if (len == -1) + if (len == -1) { len = -socket_error(); - + } return len; } @@ -236,10 +245,19 @@ 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; } -- 1.7.12.1