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 B11D2199939; Tue, 30 Sep 2025 14:50:01 +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=1759243801; cv=none; b=fF0gXY/MHPF1PXgx2yygYWO54Xl9Zo0XWy+GmAmHR/EWxjWw1M4RxavxRS4K3ofIIpdS4hYHOO8SMcZVnS/ktrrVMB9AhPQM3vdAZnrTxq0S29YxvyoyVG9BR0x1fCnX5pTKY1MP/1qjX5imyFdGX/FT3/yffRWT54oY1eAo1eo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759243801; c=relaxed/simple; bh=BnrGFrI3wpHR297IEV4jvW2GUn+A0f8jL0+pmeidA8M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PoBqD7kvrYREXgVraKBZ3Ns+qFRA2V/aeFlndjsC4J56UP0RzwN8Q4TOQcjc2CaZQp7mMXGMSP65cpCzsi8Lw+tBzWDcieHNfZxjdJEhaLq9dSRLzsWkOnTRX0td35fVUlhzSj2LfoBd+xKyBziFJJZnrAToGK1t0pIilYSQKy4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mPTjUSKx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mPTjUSKx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE80CC4CEF0; Tue, 30 Sep 2025 14:50:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1759243801; bh=BnrGFrI3wpHR297IEV4jvW2GUn+A0f8jL0+pmeidA8M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mPTjUSKxH00XsSDJmKRIGc1crRcPcr3qmIh1HbvHFHGEbMAb90FMQN0fclXKeCtF6 qCCWi4sR5NZL3nwEDaU4pOLShX7LBHJrnlshDiZH17F3YVwx2cKDmmZ5nQTXROFJGh Q7MhXvFaq5pCHlQqAg9ApBAB63rWooAeeBq37+bg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Thomas Gleixner , Nitesh Narayan Lal , Ming Lei , Sasha Levin Subject: [PATCH 5.4 21/81] genirq: Provide new interfaces for affinity hints Date: Tue, 30 Sep 2025 16:46:23 +0200 Message-ID: <20250930143820.554277816@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250930143819.654157320@linuxfoundation.org> References: <20250930143819.654157320@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner [ Upstream commit 65c7cdedeb3026fabcc967a7aae2f755ad4d0783 ] The discussion about removing the side effect of irq_set_affinity_hint() of actually applying the cpumask (if not NULL) as affinity to the interrupt, unearthed a few unpleasantries: 1) The modular perf drivers rely on the current behaviour for the very wrong reasons. 2) While none of the other drivers prevents user space from changing the affinity, a cursorily inspection shows that there are at least expectations in some drivers. #1 needs to be cleaned up anyway, so that's not a problem #2 might result in subtle regressions especially when irqbalanced (which nowadays ignores the affinity hint) is disabled. Provide new interfaces: irq_update_affinity_hint() - Only sets the affinity hint pointer irq_set_affinity_and_hint() - Set the pointer and apply the affinity to the interrupt Make irq_set_affinity_hint() a wrapper around irq_apply_affinity_hint() and document it to be phased out. Signed-off-by: Thomas Gleixner Signed-off-by: Nitesh Narayan Lal Signed-off-by: Thomas Gleixner Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20210501021832.743094-1-jesse.brandeburg@intel.com Link: https://lore.kernel.org/r/20210903152430.244937-2-nitesh@redhat.com Stable-dep-of: 915470e1b44e ("i40e: fix IRQ freeing in i40e_vsi_request_irq_msix error path") Signed-off-by: Sasha Levin --- include/linux/interrupt.h | 53 ++++++++++++++++++++++++++++++++++++++- kernel/irq/manage.c | 8 +++--- 2 files changed, 56 insertions(+), 5 deletions(-) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 85a5d13a7dc9c..7c06e33ad05ec 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -309,7 +309,46 @@ extern int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask); extern int irq_can_set_affinity(unsigned int irq); extern int irq_select_affinity(unsigned int irq); -extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m); +extern int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m, + bool setaffinity); + +/** + * irq_update_affinity_hint - Update the affinity hint + * @irq: Interrupt to update + * @m: cpumask pointer (NULL to clear the hint) + * + * Updates the affinity hint, but does not change the affinity of the interrupt. + */ +static inline int +irq_update_affinity_hint(unsigned int irq, const struct cpumask *m) +{ + return __irq_apply_affinity_hint(irq, m, false); +} + +/** + * irq_set_affinity_and_hint - Update the affinity hint and apply the provided + * cpumask to the interrupt + * @irq: Interrupt to update + * @m: cpumask pointer (NULL to clear the hint) + * + * Updates the affinity hint and if @m is not NULL it applies it as the + * affinity of that interrupt. + */ +static inline int +irq_set_affinity_and_hint(unsigned int irq, const struct cpumask *m) +{ + return __irq_apply_affinity_hint(irq, m, true); +} + +/* + * Deprecated. Use irq_update_affinity_hint() or irq_set_affinity_and_hint() + * instead. + */ +static inline int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) +{ + return irq_set_affinity_and_hint(irq, m); +} + extern int irq_update_affinity_desc(unsigned int irq, struct irq_affinity_desc *affinity); @@ -341,6 +380,18 @@ static inline int irq_can_set_affinity(unsigned int irq) static inline int irq_select_affinity(unsigned int irq) { return 0; } +static inline int irq_update_affinity_hint(unsigned int irq, + const struct cpumask *m) +{ + return -EINVAL; +} + +static inline int irq_set_affinity_and_hint(unsigned int irq, + const struct cpumask *m) +{ + return -EINVAL; +} + static inline int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) { diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 05601bcd30118..32513a2e26eb0 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -448,7 +448,8 @@ int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask) } EXPORT_SYMBOL_GPL(irq_force_affinity); -int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) +int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m, + bool setaffinity) { unsigned long flags; struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL); @@ -457,12 +458,11 @@ int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) return -EINVAL; desc->affinity_hint = m; irq_put_desc_unlock(desc, flags); - /* set the initial affinity to prevent every interrupt being on CPU0 */ - if (m) + if (m && setaffinity) __irq_set_affinity(irq, m, false); return 0; } -EXPORT_SYMBOL_GPL(irq_set_affinity_hint); +EXPORT_SYMBOL_GPL(__irq_apply_affinity_hint); static void irq_affinity_notify(struct work_struct *work) { -- 2.51.0