[v2] misc: Remove variable-length arrays on the stack

[PATCH v2 05/11] hw/net/e1000e_core: Use definition to avoid dynamic stack allocation

Peter Maydell posted 11 patches 3 years, 5 months ago

Diff against v1
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Maintainers: Samuel Thibault <samuel.thibault@ens-lyon.org>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, "Cédric Le Goater" <clg@kaod.org>, David Gibson <david@gibson.dropbear.id.au>, Greg Kurz <groug@kaod.org>, Dmitry Fleytman <dmitry.fleytman@gmail.com>, Jason Wang <jasowang@redhat.com>, Gerd Hoffmann <kraxel@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>

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[PATCH v2 05/11] hw/net/e1000e_core: Use definition to avoid dynamic stack allocation

Posted by Peter Maydell 3 years, 5 months ago

From: Philippe Mathieu-Daudé <philmd@redhat.com>

The compiler isn't clever enough to figure 'min_buf_size'
is a constant, so help it by using a definitions instead.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/net/e1000e_core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c
index 208e3e0d798..82aa61fedcd 100644
--- a/hw/net/e1000e_core.c
+++ b/hw/net/e1000e_core.c
@@ -1622,15 +1622,16 @@ e1000e_rx_fix_l4_csum(E1000ECore *core, struct NetRxPkt *pkt)
     }
 }
 
+/* Min. octets in an ethernet frame sans FCS */
+#define MIN_BUF_SIZE 60
+
 ssize_t
 e1000e_receive_iov(E1000ECore *core, const struct iovec *iov, int iovcnt)
 {
     static const int maximum_ethernet_hdr_len = (14 + 4);
-    /* Min. octets in an ethernet frame sans FCS */
-    static const int min_buf_size = 60;
 
     uint32_t n = 0;
-    uint8_t min_buf[min_buf_size];
+    uint8_t min_buf[MIN_BUF_SIZE];
     struct iovec min_iov;
     uint8_t *filter_buf;
     size_t size, orig_size;
-- 
2.25.1