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authorVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>2017-05-16 12:45:29 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2017-06-06 20:18:35 +0200
commitf250a42ddaee042ad2eb02022a3ebd18fcf987de (patch)
treebb2c0a70e07002bebd2331c9f57d47442be3aed0 /nbd
parent7e6478e7d4f2c4b607069bf488d57089a9d3244b (diff)
nbd: strict nbd_wr_syncv
nbd_wr_syncv is called either from coroutine or from client negotiation code, when socket is in blocking mode. So, -EAGAIN is impossible. Furthermore, EAGAIN is confusing, as, what to read/write again? With EAGAIN as a return code we don't know how much data is already read or written by the function, so in case of EAGAIN the whole communication is broken. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20170516094533.6160-2-vsementsov@virtuozzo.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'nbd')
-rw-r--r--nbd/common.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/nbd/common.c b/nbd/common.c
index dccbb8e9de..4db45b3ede 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -20,6 +20,10 @@
#include "qapi/error.h"
#include "nbd-internal.h"
+/* nbd_wr_syncv
+ * The function may be called from coroutine or from non-coroutine context.
+ * When called from non-coroutine context @ioc must be in blocking mode.
+ */
ssize_t nbd_wr_syncv(QIOChannel *ioc,
struct iovec *iov,
size_t niov,
@@ -42,11 +46,8 @@ ssize_t nbd_wr_syncv(QIOChannel *ioc,
len = qio_channel_writev(ioc, local_iov, nlocal_iov, &local_err);
}
if (len == QIO_CHANNEL_ERR_BLOCK) {
- if (qemu_in_coroutine()) {
- qio_channel_yield(ioc, do_read ? G_IO_IN : G_IO_OUT);
- } else {
- return -EAGAIN;
- }
+ assert(qemu_in_coroutine());
+ qio_channel_yield(ioc, do_read ? G_IO_IN : G_IO_OUT);
continue;
}
if (len < 0) {