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Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJaQB-0000000Aojl-1snZ; Thu, 13 Nov 2025 16:43:43 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJaQ9-0000000AojF-07DW for linux-arm-kernel@lists.infradead.org; Thu, 13 Nov 2025 16:43:42 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 48D6412FC; Thu, 13 Nov 2025 08:43:31 -0800 (PST) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 405C93F63F; Thu, 13 Nov 2025 08:43:34 -0800 (PST) Message-ID: <0b4e74a8-6a8a-429d-92a7-35df8ef04e9c@arm.com> Date: Thu, 13 Nov 2025 16:43:32 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 14/33] arm_mpam: Probe hardware to find the supported partid/pmg values To: Fenghua Yu , james.morse@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, bobo.shaobowang@huawei.com, carl@os.amperecomputing.com, catalin.marinas@arm.com, dakr@kernel.org, dave.martin@arm.com, david@redhat.com, dfustini@baylibre.com, gregkh@linuxfoundation.org, gshan@redhat.com, guohanjun@huawei.com, jeremy.linton@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, peternewman@google.com, quic_jiles@quicinc.com, rafael@kernel.org, robh@kernel.org, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, sudeep.holla@arm.com, tan.shaopeng@fujitsu.com, will@kernel.org, xhao@linux.alibaba.com, Shaopeng Tan References: <20251107123450.664001-1-ben.horgan@arm.com> <20251107123450.664001-15-ben.horgan@arm.com> <90c483a2-a7e0-4c87-a3da-8643bec63879@nvidia.com> From: Ben Horgan Content-Language: en-US In-Reply-To: <90c483a2-a7e0-4c87-a3da-8643bec63879@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251113_084341_185673_B3E36A8F X-CRM114-Status: GOOD ( 13.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Fenghua, On 11/13/25 03:50, Fenghua Yu wrote: > Hi, Ben and James, > > On 11/7/25 04:34, Ben Horgan wrote: >> From: James Morse > [SNIP] > >> +static struct mpam_msc_ris *mpam_get_or_create_ris(struct mpam_msc *msc, >> +                           u8 ris_idx) >> +{ >> +    int err; >> +    struct mpam_msc_ris *ris; >> + >> +    lockdep_assert_held(&mpam_list_lock); >> + >> +    if (!test_bit(ris_idx, &msc->ris_idxs)) { >> +        err = mpam_ris_create_locked(msc, ris_idx, MPAM_CLASS_UNKNOWN, >> +                         0, 0); >> +        if (err) >> +            return ERR_PTR(err); >> +    } >> + >> +    list_for_each_entry(ris, &msc->ris, msc_list) { >> +        if (ris->ris_idx == ris_idx) >> +            return ris; >> +    } >> + >> +    return ERR_PTR(-ENOENT); >> +} >> + >>   static int mpam_msc_hw_probe(struct mpam_msc *msc) >>   { >>       u64 idr; >> +    u16 partid_max; >> +    u8 ris_idx, pmg_max; >> +    struct mpam_msc_ris *ris; >>       struct device *dev = &msc->pdev->dev; >>         lockdep_assert_held(&msc->probe_lock); >> @@ -464,6 +564,40 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc) >>           return -EIO; >>       } >>   +    /* Grab an IDR value to find out how many RIS there are */ >> +    mutex_lock(&msc->part_sel_lock); >> +    idr = mpam_msc_read_idr(msc); >> +    mutex_unlock(&msc->part_sel_lock); >> + >> +    msc->ris_max = FIELD_GET(MPAMF_IDR_RIS_MAX, idr); >> + >> +    /* Use these values so partid/pmg always starts with a valid >> value */ >> +    msc->partid_max = FIELD_GET(MPAMF_IDR_PARTID_MAX, idr); >> +    msc->pmg_max = FIELD_GET(MPAMF_IDR_PMG_MAX, idr); >> + >> +    for (ris_idx = 0; ris_idx <= msc->ris_max; ris_idx++) { >> +        mutex_lock(&msc->part_sel_lock); >> +        __mpam_part_sel(ris_idx, 0, msc); >> +        idr = mpam_msc_read_idr(msc); >> +        mutex_unlock(&msc->part_sel_lock); >> + >> +        partid_max = FIELD_GET(MPAMF_IDR_PARTID_MAX, idr); >> +        pmg_max = FIELD_GET(MPAMF_IDR_PMG_MAX, idr); >> +        msc->partid_max = min(msc->partid_max, partid_max); >> +        msc->pmg_max = min(msc->pmg_max, pmg_max); >> + >> +        mutex_lock(&mpam_list_lock); >> +        ris = mpam_get_or_create_ris(msc, ris_idx); >> +        mutex_unlock(&mpam_list_lock); >> +        if (IS_ERR(ris)) >> +            return PTR_ERR(ris); > > It's better to destroy ris's that were previously created before this > failed ris? Otherwise, there is a memory leak for those allocated ris's? This should be handled by mpam_disable() which is run on probe failure. > > Thanks. > > -Fenghua Thanks, Ben