On 10/10/20 8:07 AM, David Gibson wrote:
On Fri, Oct 09, 2020 at 07:02:56AM -0700, Elena Afanasova wrote:
>From 09905773a00e417d3a37c12350d9e55466fdce8a Mon Sep 17 00:00:00 2001
From: Elena Afanasova <eafanas...@gmail.com>
Date: Fri, 9 Oct 2020 06:41:36 -0700
Subject: [PATCH] hw/net: move allocation to the heap due to very large stack
frame
Patch looks fine, but some more details of the motivation would be
nice. I wouldn't have thought that the size of a network packet
counted as a "very large" stack frame by userspace standards.
Maybe academia doing research on "super jumbo frames"?
"Super jumbo frames ... increase the path MTU of high-performance
national research and education networks from 1500 bytes to 9000
bytes or so, a subsequent increase, possibly to 64,000 bytes"
(https://en.wikipedia.org/wiki/Jumbo_frame#Super_jumbo_frames)
Signed-off-by: Elena Afanasova <eafanas...@gmail.com>
---
hw/net/spapr_llan.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/hw/net/spapr_llan.c b/hw/net/spapr_llan.c
index 2093f1bad0..581320a0e7 100644
--- a/hw/net/spapr_llan.c
+++ b/hw/net/spapr_llan.c
@@ -688,7 +688,8 @@ static target_ulong h_send_logical_lan(PowerPCCPU *cpu,
SpaprVioDevice *sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
SpaprVioVlan *dev = VIO_SPAPR_VLAN_DEVICE(sdev);
unsigned total_len;
- uint8_t *lbuf, *p;
+ uint8_t *p;
+ g_autofree uint8_t *lbuf = NULL;
int i, nbufs;
int ret;
@@ -729,7 +730,7 @@ static target_ulong h_send_logical_lan(PowerPCCPU *cpu,
return H_RESOURCE;
}
- lbuf = alloca(total_len);
+ lbuf = g_malloc(total_len);
p = lbuf;
for (i = 0; i < nbufs; i++) {
ret = spapr_vio_dma_read(sdev, VLAN_BD_ADDR(bufs[i]),
