Re: [libvirt] [PATCH] nodedev: Fix gfeature size to be according to running kernel
On 08/08/2015 05:34 AM, Moshe Levi wrote:
This patch add virNetDevGetGFeaturesSize to get the supported
gfeature size from the kernel
---
This is interesting/possibly useful, but it doesn't fix the crash that
users are experiencing. Here is a patch that should fix the crash:
https://www.redhat.com/archives/libvir-list/2015-August/msg00382.html
I would rather have that patch pushed before this one (which will mean
rebasing and resolving some merge conflicts).
src/util/virnetdev.c | 60
++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 56 insertions(+), 4 deletions(-)
diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
index 1e20789..3fdf4bb 100644
--- a/src/util/virnetdev.c
+++ b/src/util/virnetdev.c
@@ -89,8 +89,10 @@ VIR_LOG_INIT("util.netdev");
#define RESOURCE_FILE_LEN 4096
#if HAVE_DECL_ETHTOOL_GFEATURES
+#define ETH_GSTRING_LEN 32
Where does the "32" come from? Is it from ETH_GSTRING_LEN (defined in
ethtool.h)? If so, why not just use that directly instead of #defining a
new one?
# define TX_UDP_TNL 25
I'll keep asking this every time I encounter it until I get a response -
when I look at the ethtool source files in the kernel, it looks to me
like the index for this capability should be 26 and not 25. Where/how
did you arrive at the value of 25?
-# define GFEATURES_SIZE 2
+# define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+# define FEATURE_BITS_TO_BLOCKS(n_bits) DIV_ROUND_UP(n_bits, 32U)
# define FEATURE_WORD(blocks, index, field) ((blocks)[(index) / 32U].field)
# define FEATURE_FIELD_FLAG(index) (1U << (index) % 32U)
# define FEATURE_BIT_IS_SET(blocks, index, field) \
@@ -3110,6 +3112,53 @@ virNetDevGFeatureAvailable(const char *ifname, struct
ethtool_gfeatures *cmd)
ret = FEATURE_BIT_IS_SET(cmd->features, TX_UDP_TNL, active);
return ret;
}
+/**
+ * virNetDevGetGFeaturesSize
+ * This function return the number of gfeatures supported in
+ * the kernel
+ *
+ * @ifname: name of the interface
+ *
+ * Returns gfeature size on success, and 0 on failure or not supported.
+ */
+ static int
+virNetDevGetGFeaturesSize(const char *ifname)
+{
+ struct {
+ struct ethtool_sset_info hdr;
+ uint32_t buf[1];
+ } sset_info;
+ struct ethtool_gstrings *strings;
+ uint32_t size = 0;
+
+ sset_info.hdr.cmd = ETHTOOL_GSSET_INFO;
+ sset_info.hdr.reserved = 0;
+ sset_info.hdr.sset_mask = 1ULL << ETH_SS_FEATURES;
+
+ if (virNetDevSendEthtoolIoctl(ifname, &sset_info) == -1)
+ return size;
virNetDevSendEthtoolIoctl() logs an error message, but it looks like you
want for an error to be swallowed here (just returning size = 0). If
that's the case then virNetDevSendEthtoolIoctl() needs to be reworked to
not log errors, then every caller to it needs to log the error.
+ size = sset_info.hdr.sset_mask ? sset_info.hdr.data[0] : 0;
+
+ if (VIR_ALLOC_VAR(strings, struct ethtool_gstrings, sizeof(*strings) + size *
ETH_GSTRING_LEN)) {
+ size = 0;
+ return size;
+ }
+
+ strings->cmd = ETHTOOL_GSTRINGS;
+ strings->string_set = ETH_SS_FEATURES;
+ strings->len = size;
+ if (size != 0 && virNetDevSendEthtoolIoctl(ifname, strings) == -1) {
+ size = 0;
+ goto cleanup;
+ }
+
+ size = FEATURE_BITS_TO_BLOCKS(size);
+
+ cleanup:
+ VIR_FREE(strings);
+ return size;
+}
+
# endif
@@ -3189,9 +3238,12 @@ virNetDevGetFeatures(const char *ifname,
# if HAVE_DECL_ETHTOOL_GFEATURES
g_cmd.cmd = ETHTOOL_GFEATURES;
- g_cmd.size = GFEATURES_SIZE;
- if (virNetDevGFeatureAvailable(ifname, &g_cmd))
- ignore_value(virBitmapSetBit(*out, VIR_NET_DEV_FEAT_TXUDPTNL));
+ g_cmd.size = virNetDevGetGFeaturesSize(ifname);
+ if (g_cmd.size == 0)
+ VIR_DEBUG("GFeatures unsupported or failure in getting GFeatures size on
ifname %s", ifname);
Should this failure really be ignored? Or should it lead to failure of
the entire operation?
+ else
+ if (virNetDevGFeatureAvailable(ifname, &g_cmd))
+ ignore_value(virBitmapSetBit(*out, VIR_NET_DEV_FEAT_TXUDPTNL));
# endif
if (virNetDevRDMAFeature(ifname, out) < 0)