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Message-ID: <5a2d11a599aa5b0cc6141072c01accfb7758650c.1723045898.git.ecree.xilinx@gmail.com>
Date: Wed, 7 Aug 2024 17:06:12 +0100
From: <edward.cree@....com>
To: <davem@...emloft.net>, <kuba@...nel.org>, <edumazet@...gle.com>,
<pabeni@...hat.com>
CC: Edward Cree <ecree.xilinx@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v2 net 1/2] net: ethtool: fix off-by-one error in max RSS context IDs
From: Edward Cree <ecree.xilinx@...il.com>
Both ethtool_ops.rxfh_max_context_id and the default value used when
it's not specified are supposed to be exclusive maxima (the former
is documented as such; the latter, U32_MAX, cannot be used as an ID
since it equals ETH_RXFH_CONTEXT_ALLOC), but xa_alloc() expects an
inclusive maximum.
Subtract one from 'limit' to produce an inclusive maximum, and pass
that to xa_alloc().
Increase bnxt's max by one to prevent a (very minor) regression, as
BNXT_MAX_ETH_RSS_CTX is an inclusive max. This is safe since bnxt
is not actually hard-limited; BNXT_MAX_ETH_RSS_CTX is just a
leftover from old driver code that managed context IDs itself.
Rename rxfh_max_context_id to rxfh_max_num_contexts to make its
semantics (hopefully) more obvious.
Fixes: 847a8ab18676 ("net: ethtool: let the core choose RSS context IDs")
Signed-off-by: Edward Cree <ecree.xilinx@...il.com>
---
drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c | 2 +-
include/linux/ethtool.h | 10 +++++-----
net/ethtool/ioctl.c | 5 +++--
3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
index ab8e3f197e7b..9dadc89378f0 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
@@ -5290,7 +5290,7 @@ void bnxt_ethtool_free(struct bnxt *bp)
const struct ethtool_ops bnxt_ethtool_ops = {
.cap_link_lanes_supported = 1,
.cap_rss_ctx_supported = 1,
- .rxfh_max_context_id = BNXT_MAX_ETH_RSS_CTX,
+ .rxfh_max_num_contexts = BNXT_MAX_ETH_RSS_CTX + 1,
.rxfh_indir_space = BNXT_MAX_RSS_TABLE_ENTRIES_P5,
.rxfh_priv_size = sizeof(struct bnxt_rss_ctx),
.supported_coalesce_params = ETHTOOL_COALESCE_USECS |
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 303fda54ef17..989c94eddb2b 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -736,10 +736,10 @@ struct kernel_ethtool_ts_info {
* @rxfh_key_space: same as @rxfh_indir_space, but for the key.
* @rxfh_priv_size: size of the driver private data area the core should
* allocate for an RSS context (in &struct ethtool_rxfh_context).
- * @rxfh_max_context_id: maximum (exclusive) supported RSS context ID. If this
- * is zero then the core may choose any (nonzero) ID, otherwise the core
- * will only use IDs strictly less than this value, as the @rss_context
- * argument to @create_rxfh_context and friends.
+ * @rxfh_max_num_contexts: maximum (exclusive) supported RSS context ID.
+ * If this is zero then the core may choose any (nonzero) ID, otherwise
+ * the core will only use IDs strictly less than this value, as the
+ * @rss_context argument to @create_rxfh_context and friends.
* @supported_coalesce_params: supported types of interrupt coalescing.
* @supported_ring_params: supported ring params.
* @get_drvinfo: Report driver/device information. Modern drivers no
@@ -954,7 +954,7 @@ struct ethtool_ops {
u32 rxfh_indir_space;
u16 rxfh_key_space;
u16 rxfh_priv_size;
- u32 rxfh_max_context_id;
+ u32 rxfh_max_num_contexts;
u32 supported_coalesce_params;
u32 supported_ring_params;
void (*get_drvinfo)(struct net_device *, struct ethtool_drvinfo *);
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 8ca13208d240..a8e276ecf723 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1449,12 +1449,13 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
}
if (ops->create_rxfh_context) {
- u32 limit = ops->rxfh_max_context_id ?: U32_MAX;
+ u32 limit = ops->rxfh_max_num_contexts ?: U32_MAX;
u32 ctx_id;
/* driver uses new API, core allocates ID */
ret = xa_alloc(&dev->ethtool->rss_ctx, &ctx_id, ctx,
- XA_LIMIT(1, limit), GFP_KERNEL_ACCOUNT);
+ XA_LIMIT(1, limit - 1),
+ GFP_KERNEL_ACCOUNT);
if (ret < 0) {
kfree(ctx);
goto out;
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