[PATCH v2] use pr_warn_ratelimited() for vq_err()

[John Levon <john.levon@nutanix.com>]

vq_err() is used to report various failure states in vhost code, but by
default uses pr_debug(), and as a result doesn't record anything unless
enabled via dynamic debug. We'll change this so we get something recorded
in the log in these failure cases. Guest VMs (and userspace) can trigger
some of these messages, so we want to use the pr_warn_ratelimited()
variant. However, on DEBUG kernels, we'd like to get everything, so we use
pr_warn() then.

Signed-off-by: John Levon <john.levon@nutanix.com>
---
v2: use pr_warn() for DEBUG kernels
---
 drivers/vhost/vhost.h | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index b063324c7669..10007bd49f84 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -228,10 +228,16 @@ int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
 void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
 			  struct vhost_iotlb_map *map);
 
-#define vq_err(vq, fmt, ...) do {                                  \
-		pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
-		if ((vq)->error_ctx)                               \
-				eventfd_signal((vq)->error_ctx, 1);\
+#ifdef DEBUG
+#define vq_pr_warn pr_warn
+#else
+#define vq_pr_warn pr_warn_ratelimited
+#endif
+
+#define vq_err(vq, fmt, ...) do {                                \
+		vq_pr_warn(pr_fmt(fmt), ##__VA_ARGS__);          \
+		if ((vq)->error_ctx)                             \
+			eventfd_signal((vq)->error_ctx, 1);      \
 	} while (0)
 
 enum {
-- 
2.25.1