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Message-ID: <6dfa1ca9-7067-ca73-ff38-0bf517b5ed7c@intel.com>
Date: Fri, 29 Sep 2023 11:20:50 -0700
From: Jacob Keller <jacob.e.keller@...el.com>
To: <edward.cree@....com>, <linux-net-drivers@....com>, <davem@...emloft.net>,
<kuba@...nel.org>, <edumazet@...gle.com>, <pabeni@...hat.com>
CC: Edward Cree <ecree.xilinx@...il.com>, <netdev@...r.kernel.org>,
<habetsm.xilinx@...il.com>, <sudheer.mogilappagari@...el.com>,
<jdamato@...tly.com>, <andrew@...n.ch>, <mw@...ihalf.com>,
<linux@...linux.org.uk>, <sgoutham@...vell.com>, <gakula@...vell.com>,
<sbhatta@...vell.com>, <hkelam@...vell.com>, <saeedm@...dia.com>,
<leon@...nel.org>
Subject: Re: [PATCH v4 net-next 3/7] net: ethtool: record custom RSS contexts
in the XArray
On 9/27/2023 11:13 AM, edward.cree@....com wrote:
> From: Edward Cree <ecree.xilinx@...il.com>
>
> Since drivers are still choosing the context IDs, we have to force the
> XArray to use the ID they've chosen rather than picking one ourselves,
> and handle the case where they give us an ID that's already in use.
>
> Signed-off-by: Edward Cree <ecree.xilinx@...il.com>
> ---
> include/linux/ethtool.h | 14 ++++++++
> net/ethtool/ioctl.c | 73 +++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 85 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
> index bb11cb2f477d..229a23571008 100644
> --- a/include/linux/ethtool.h
> +++ b/include/linux/ethtool.h
> @@ -194,6 +194,17 @@ static inline u8 *ethtool_rxfh_context_key(struct ethtool_rxfh_context *ctx)
> return (u8 *)(ethtool_rxfh_context_indir(ctx) + ctx->indir_size);
> }
>
> +static inline size_t ethtool_rxfh_context_size(u32 indir_size, u32 key_size,
> + u16 priv_size)
> +{
> + size_t indir_bytes = array_size(indir_size, sizeof(u32));
> + size_t flex_len;
> +
> + flex_len = size_add(size_add(indir_bytes, key_size),
> + ALIGN(priv_size, sizeof(u32)));
> + return struct_size((struct ethtool_rxfh_context *)0, data, flex_len);
> +}
> +
Ah, we already have to use a flexible area to handle the indirection
table, and this way the core is the only one responsible for allocating
and freeing the memory.
Reviewed-by: Jacob Keller <jacob.e.keller@...el.com>
> /* declare a link mode bitmap */
> #define __ETHTOOL_DECLARE_LINK_MODE_MASK(name) \
> DECLARE_BITMAP(name, __ETHTOOL_LINK_MODE_MASK_NBITS)
> @@ -731,6 +742,8 @@ struct ethtool_mm_stats {
> * will remain unchanged.
> * Returns a negative error code or zero. An error code must be returned
> * if at least one unsupported change was requested.
> + * @rxfh_priv_size: size of the driver private data area the core should
> + * allocate for an RSS context.
> * @get_rxfh_context: Get the contents of the RX flow hash indirection table,
> * hash key, and/or hash function assiciated to the given rss context.
> * Returns a negative error code or zero.
> @@ -824,6 +837,7 @@ struct ethtool_ops {
> u32 cap_link_lanes_supported:1;
> u32 supported_coalesce_params;
> u32 supported_ring_params;
> + u16 rxfh_priv_size;
> void (*get_drvinfo)(struct net_device *, struct ethtool_drvinfo *);
> int (*get_regs_len)(struct net_device *);
> void (*get_regs)(struct net_device *, struct ethtool_regs *, void *);
> diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
> index de78b24fffc9..1d13bc8fbb75 100644
> --- a/net/ethtool/ioctl.c
> +++ b/net/ethtool/ioctl.c
> @@ -1249,6 +1249,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
> {
> int ret;
> const struct ethtool_ops *ops = dev->ethtool_ops;
> + struct ethtool_rxfh_context *ctx = NULL;
> struct ethtool_rxnfc rx_rings;
> struct ethtool_rxfh rxfh;
> u32 dev_indir_size = 0, dev_key_size = 0, i;
> @@ -1256,7 +1257,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
> u8 *hkey = NULL;
> u8 *rss_config;
> u32 rss_cfg_offset = offsetof(struct ethtool_rxfh, rss_config[0]);
> - bool delete = false;
> + bool create = false, delete = false;
>
> if (!ops->get_rxnfc || !ops->set_rxfh)
> return -EOPNOTSUPP;
> @@ -1275,6 +1276,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
> /* Most drivers don't handle rss_context, check it's 0 as well */
> if (rxfh.rss_context && !ops->set_rxfh_context)
> return -EOPNOTSUPP;
> + create = rxfh.rss_context == ETH_RXFH_CONTEXT_ALLOC;
>
> /* If either indir, hash key or function is valid, proceed further.
> * Must request at least one change: indir size, hash key or function.
> @@ -1332,13 +1334,42 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
> }
> }
>
> + if (create) {
> + if (delete) {
> + ret = -EINVAL;
> + goto out;
> + }
> + ctx = kzalloc(ethtool_rxfh_context_size(dev_indir_size,
> + dev_key_size,
> + ops->rxfh_priv_size),
> + GFP_KERNEL_ACCOUNT);
> + if (!ctx) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + ctx->indir_size = dev_indir_size;
> + ctx->key_size = dev_key_size;
> + ctx->hfunc = rxfh.hfunc;
> + ctx->priv_size = ops->rxfh_priv_size;
> + } else if (rxfh.rss_context) {
> + ctx = xa_load(&dev->ethtool->rss_ctx, rxfh.rss_context);
> + if (!ctx) {
> + ret = -ENOENT;
> + goto out;
> + }
> + }
> +
> if (rxfh.rss_context)
> ret = ops->set_rxfh_context(dev, indir, hkey, rxfh.hfunc,
> &rxfh.rss_context, delete);
> else
> ret = ops->set_rxfh(dev, indir, hkey, rxfh.hfunc);
> - if (ret)
> + if (ret) {
> + if (create)
> + /* failed to create, free our new tracking entry */
> + kfree(ctx);
> goto out;
> + }
>
> if (copy_to_user(useraddr + offsetof(struct ethtool_rxfh, rss_context),
> &rxfh.rss_context, sizeof(rxfh.rss_context)))
> @@ -1351,6 +1382,44 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
> else if (rxfh.indir_size != ETH_RXFH_INDIR_NO_CHANGE)
> dev->priv_flags |= IFF_RXFH_CONFIGURED;
> }
> + /* Update rss_ctx tracking */
> + if (create) {
> + /* Ideally this should happen before calling the driver,
> + * so that we can fail more cleanly; but we don't have the
> + * context ID until the driver picks it, so we have to
> + * wait until after.
> + */
> + if (WARN_ON(xa_load(&dev->ethtool->rss_ctx, rxfh.rss_context))) {
> + /* context ID reused, our tracking is screwed */
> + kfree(ctx);
> + goto out;
> + }
> + /* Allocate the exact ID the driver gave us */
> + if (xa_is_err(xa_store(&dev->ethtool->rss_ctx, rxfh.rss_context,
> + ctx, GFP_KERNEL))) {
> + kfree(ctx);
> + goto out;
> + }
> + ctx->indir_no_change = rxfh.indir_size == ETH_RXFH_INDIR_NO_CHANGE;
> + ctx->key_no_change = !rxfh.key_size;
> + }
> + if (delete) {
> + WARN_ON(xa_erase(&dev->ethtool->rss_ctx, rxfh.rss_context) != ctx);
> + kfree(ctx);
> + } else if (ctx) {
> + if (indir) {
> + for (i = 0; i < dev_indir_size; i++)
> + ethtool_rxfh_context_indir(ctx)[i] = indir[i];
> + ctx->indir_no_change = 0;
> + }
> + if (hkey) {
> + memcpy(ethtool_rxfh_context_key(ctx), hkey,
> + dev_key_size);
> + ctx->key_no_change = 0;
> + }
> + if (rxfh.hfunc != ETH_RSS_HASH_NO_CHANGE)
> + ctx->hfunc = rxfh.hfunc;
> + }
>
> out:
> kfree(rss_config);
>
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