[PATCH v3 09/10] hw/char: Simplify when qemu_chr_fe_write() could not write

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

If no chars were written, avoid to access the FIFO.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/char/cadence_uart.c | 2 +-
 hw/char/ibex_uart.c    | 2 +-
 hw/char/sifive_uart.c  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index 0dfa356b6d0..8908ebbe34a 100644
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -316,7 +316,7 @@ static gboolean cadence_uart_xmit(void *do_not_use, GIOCondition cond,
 
     ret = qemu_chr_fe_write(&s->chr, s->tx_fifo, s->tx_count);
 
-    if (ret >= 0) {
+    if (ret > 0) {
         s->tx_count -= ret;
         memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_count);
     }
diff --git a/hw/char/ibex_uart.c b/hw/char/ibex_uart.c
index d6f0d18c777..b7843c7a741 100644
--- a/hw/char/ibex_uart.c
+++ b/hw/char/ibex_uart.c
@@ -161,7 +161,7 @@ static gboolean ibex_uart_xmit(void *do_not_use, GIOCondition cond,
 
     ret = qemu_chr_fe_write(&s->chr, s->tx_fifo, s->tx_level);
 
-    if (ret >= 0) {
+    if (ret > 0) {
         s->tx_level -= ret;
         memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_level);
     }
diff --git a/hw/char/sifive_uart.c b/hw/char/sifive_uart.c
index e7357d585a1..e5b381425a9 100644
--- a/hw/char/sifive_uart.c
+++ b/hw/char/sifive_uart.c
@@ -83,7 +83,7 @@ static gboolean sifive_uart_xmit(void *do_not_use, GIOCondition cond,
                                    fifo8_num_used(&s->tx_fifo), &numptr);
     ret = qemu_chr_fe_write(&s->chr, characters, numptr);
 
-    if (ret >= 0) {
+    if (ret > 0) {
         /* We wrote the data, actually pop the fifo */
         fifo8_pop_bufptr(&s->tx_fifo, ret, NULL);
     }
-- 
2.51.0