[PATCH] vhost: reduce stack usage in log_used

[Li Wang]

Fix the warning: [-Werror=-Wframe-larger-than=]

drivers/vhost/vhost.c: In function log_used:
drivers/vhost/vhost.c:1906:1:
warning: the frame size of 1040 bytes is larger than 1024 bytes

Signed-off-by: Li Wang <li.w...@windriver.com>
---
 drivers/vhost/vhost.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b45519c..41769de 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1884,25 +1884,31 @@ static int log_write_hva(struct vhost_virtqueue *vq, 
u64 hva, u64 len)
 
 static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
 {
-       struct iovec iov[64];
+       struct iovec *iov;
        int i, ret;
 
        if (!vq->iotlb)
                return log_write(vq->log_base, vq->log_addr + used_offset, len);
 
+       iov = kcalloc(64, sizeof(*iov), GFP_KERNEL);
+       if (!iov)
+               return -ENOMEM;
+
        ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
                             len, iov, 64, VHOST_ACCESS_WO);
        if (ret < 0)
-               return ret;
+               goto out;
 
        for (i = 0; i < ret; i++) {
                ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
                                    iov[i].iov_len);
                if (ret)
-                       return ret;
+                       goto out;
        }
 
-       return 0;
+out:
+       kfree(iov);
+       return ret;
 }
 
 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
-- 
2.7.4