From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 77AD830F812; Sun, 8 Mar 2026 13:12:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772975548; cv=none; b=NOKt+pXW6Gj1JtDSuMgK8Iv3Ca7cm03ieK+0CPnSmk0VxuyeKvZ+CatjHP8rMKCunJJLVmf5R9WKQ4vrcvLak+Z1bRCWtwwJozfelWx6cBf9S3iZ3kjXuDbYONtrQJSDDoooZlkEPdsVKcwXzZwq5Qy74imMoq/J5HTVazWF/7w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772975548; c=relaxed/simple; bh=FvJKbZgamfnmKxUUtbTe6ppykVXHPJ9khlH2c7HuyFk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=cLN4znszP+PeL3ebsd0Xh6O92b5pI6k+78AmHegtjx6TJZT1jEtNUnBKhfCoTVwzcz3K5WgS3nwB36zDvpJ64NI/eNyksNGjtPaFp0WFgKkBZpNzwDn6i+/NjkMc0QfZaob47/XMtXUb8qhi6vjq4KngNhs/Mu3F1ZCljA8dvJM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sM9ApWEX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sM9ApWEX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B31BC116C6; Sun, 8 Mar 2026 13:12:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772975548; bh=FvJKbZgamfnmKxUUtbTe6ppykVXHPJ9khlH2c7HuyFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sM9ApWEX6RYA69c3kGZaYmhHIZPmN0lryZ+tIqPxt6rJQZPsrpyiiIj3QqjQGMarx KcGhPVNfdnbSovedWbXxRpCLIyZcUi4Z9xf8kzqqv8Q5ox0XqYpLBxAMH2FWwF2CR3 9+r967VdwMslccAUe6CZAZtJSP7XIrRCsioT/5NgzezMRXWU73X23M0++3pScSZQOY XqOMpOrURgXSsEiOcGU+2EWFm633winBqC8/B/yFDiod+WSRQRIy2Hu21chWgoMX50 lPBh+D60+gnldb5EHgHsm6Pkt9BAAbxXVHQQ4ikaK954LnWZGfz+zLU5ikkeapDV/h H8QK/PF3D5c5w== From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= To: Michael Chan , Pavan Chebbi , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Willem de Bruijn Subject: [PATCH net-next v3 1/3] ethtool: Add RSS indirection table resize helpers Date: Sun, 8 Mar 2026 14:12:15 +0100 Message-ID: <20260308131218.3172332-2-bjorn@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260308131218.3172332-1-bjorn@kernel.org> References: <20260308131218.3172332-1-bjorn@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The core locks ctx->indir_size when an RSS context is created. Some NICs (e.g. bnxt) change their indirection table size based on the channel count, because the hardware table is a shared resource. This forces drivers to reject channel changes when RSS contexts exist. Add helpers to resize indirection tables: ethtool_rxfh_can_resize() checks whether a table can be resized without modifying it. ethtool_rxfh_resize() resizes a raw u32 table in place. Folding (shrink) requires the table to be periodic at the new size; non-periodic tables are rejected. Unfolding (grow) replicates the existing pattern. Sizes must be multiples of each other. ethtool_rxfh_ctxs_can_resize() validates all non-default RSS contexts can be resized. ethtool_rxfh_ctxs_resize() applies the resize and sends ETHTOOL_MSG_RSS_NTF per resized context after releasing rss_lock. No reallocation is needed because ethtool_rxfh_ctx_alloc() reserves space for rxfh_indir_space entries, and key_off is based on that maximum. Tested-by: Pavan Chebbi Signed-off-by: Björn Töpel --- include/linux/ethtool.h | 4 ++ net/ethtool/common.c | 143 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 147 insertions(+) diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 83c375840835..e2c4aa0a3348 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h @@ -214,6 +214,10 @@ static inline u8 *ethtool_rxfh_context_key(struct ethtool_rxfh_context *ctx) } void ethtool_rxfh_context_lost(struct net_device *dev, u32 context_id); +bool ethtool_rxfh_can_resize(const u32 *tbl, u32 old_size, u32 new_size); +int ethtool_rxfh_resize(u32 *tbl, u32 old_size, u32 new_size); +int ethtool_rxfh_ctxs_can_resize(struct net_device *dev, u32 new_indir_size); +void ethtool_rxfh_ctxs_resize(struct net_device *dev, u32 new_indir_size); struct link_mode_info { int speed; diff --git a/net/ethtool/common.c b/net/ethtool/common.c index e252cf20c22f..ad6056297479 100644 --- a/net/ethtool/common.c +++ b/net/ethtool/common.c @@ -1204,6 +1204,149 @@ void ethtool_rxfh_context_lost(struct net_device *dev, u32 context_id) } EXPORT_SYMBOL(ethtool_rxfh_context_lost); +static bool rxfh_indir_is_periodic(const u32 *tbl, u32 old_size, u32 new_size) +{ + u32 i; + + for (i = new_size; i < old_size; i++) + if (tbl[i] != tbl[i % new_size]) + return false; + return true; +} + +/** + * ethtool_rxfh_can_resize - Check if an indirection table can be resized + * @tbl: indirection table + * @old_size: current number of entries in the table + * @new_size: desired number of entries + * + * Validate that @tbl can be resized from @old_size to @new_size without + * data loss. Read-only; does not modify the table. + * + * Return: true if resize is possible, false otherwise. + */ +bool ethtool_rxfh_can_resize(const u32 *tbl, u32 old_size, u32 new_size) +{ + if (new_size == old_size) + return true; + + if (new_size < old_size) { + if (old_size % new_size) + return false; + if (!rxfh_indir_is_periodic(tbl, old_size, new_size)) + return false; + return true; + } + + if (new_size % old_size) + return false; + return true; +} +EXPORT_SYMBOL(ethtool_rxfh_can_resize); + +/* Resize without validation; caller must have called can_resize first */ +static void __ethtool_rxfh_resize(u32 *tbl, u32 old_size, u32 new_size) +{ + u32 i; + + /* Grow: replicate existing pattern; shrink is a no-op on the data */ + for (i = old_size; i < new_size; i++) + tbl[i] = tbl[i % old_size]; +} + +/** + * ethtool_rxfh_resize - Fold or unfold an indirection table + * @tbl: indirection table (must have room for max(old_size, new_size) entries) + * @old_size: current number of entries in the table + * @new_size: desired number of entries + * + * Resize an RSS indirection table in place. When folding (shrinking), + * the table must be periodic with period @new_size; otherwise the + * operation is rejected. When unfolding (growing), the existing + * pattern is replicated. Both directions require the sizes to be + * multiples of each other. + * + * Return: 0 on success, -%EINVAL on failure (no mutation on failure). + */ +int ethtool_rxfh_resize(u32 *tbl, u32 old_size, u32 new_size) +{ + if (!ethtool_rxfh_can_resize(tbl, old_size, new_size)) + return -EINVAL; + + __ethtool_rxfh_resize(tbl, old_size, new_size); + return 0; +} +EXPORT_SYMBOL(ethtool_rxfh_resize); + +/** + * ethtool_rxfh_ctxs_can_resize - Validate resize for all RSS contexts + * @dev: network device + * @new_indir_size: new indirection table size + * + * Validate that the indirection tables of all non-default RSS contexts + * can be resized to @new_indir_size. Read-only; does not modify any + * context. Intended to be paired with ethtool_rxfh_ctxs_resize(). + * + * Return: 0 if all contexts can be resized, negative errno on failure. + */ +int ethtool_rxfh_ctxs_can_resize(struct net_device *dev, + u32 new_indir_size) +{ + struct ethtool_rxfh_context *ctx; + unsigned long context; + int ret = 0; + + if (!dev->ethtool_ops->rxfh_indir_space || + new_indir_size > dev->ethtool_ops->rxfh_indir_space) + return -EINVAL; + + mutex_lock(&dev->ethtool->rss_lock); + xa_for_each(&dev->ethtool->rss_ctx, context, ctx) { + u32 *indir = ethtool_rxfh_context_indir(ctx); + + if (!ethtool_rxfh_can_resize(indir, ctx->indir_size, + new_indir_size)) { + ret = -EINVAL; + goto unlock; + } + } +unlock: + mutex_unlock(&dev->ethtool->rss_lock); + return ret; +} +EXPORT_SYMBOL(ethtool_rxfh_ctxs_can_resize); + +/** + * ethtool_rxfh_ctxs_resize - Resize all RSS context indirection tables + * @dev: network device + * @new_indir_size: new indirection table size + * + * Resize the indirection table of every non-default RSS context to + * @new_indir_size. Caller must have validated with + * ethtool_rxfh_ctxs_can_resize() first. An %ETHTOOL_MSG_RSS_NTF is + * sent for each resized context. + * + * Notifications are sent outside the RSS lock to avoid holding the + * mutex during notification delivery. + */ +void ethtool_rxfh_ctxs_resize(struct net_device *dev, u32 new_indir_size) +{ + struct ethtool_rxfh_context *ctx; + unsigned long context; + + mutex_lock(&dev->ethtool->rss_lock); + xa_for_each(&dev->ethtool->rss_ctx, context, ctx) { + __ethtool_rxfh_resize(ethtool_rxfh_context_indir(ctx), + ctx->indir_size, new_indir_size); + ctx->indir_size = new_indir_size; + } + mutex_unlock(&dev->ethtool->rss_lock); + + xa_for_each(&dev->ethtool->rss_ctx, context, ctx) + ethtool_rss_notify(dev, ETHTOOL_MSG_RSS_NTF, context); +} +EXPORT_SYMBOL(ethtool_rxfh_ctxs_resize); + enum ethtool_link_medium ethtool_str_to_medium(const char *str) { int i; -- 2.53.0