From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout01.his.huawei.com (canpmsgout01.his.huawei.com [113.46.200.216]) (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 7A28536EA80; Fri, 14 Aug 2026 06:33:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.216 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786689230; cv=none; b=hwPjEHGb7ztrAbSZRr1i8KV1W/f99eWSKpaw8y1R+mbANOHDTQFsP6q4ealFt0in+t78JG89H08cbrzRO62owdPpaQJBgp8RFH+ENdIycLQRGuGwc2PlLTYoD9cDTrb5JTL+kkZOf9c02eoFEfbT8d5mQOZ296GeEh+Oqq7w7EU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786689230; c=relaxed/simple; bh=JbJUrjQct/bq7GozCgtZcnP+7bSAzDmDxzDZLz17kR8=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=m2SURfHtyHY1fL2xwxPUKl4HaOtBxa6yB3bKUBFZ5+jk+9rNYoY6fcNE5hV/cKmG4pGvar684odt52n6+Y4+BGXxCRkNNZYUFJ7SBc9aKLn03Zc/wSdF4yswJcddkScijL3kzyX5LrKR3Y3E5FBLixCZ3CRNMO+d2oulvbSOvBQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=HFV8zqPf; arc=none smtp.client-ip=113.46.200.216 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="HFV8zqPf" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=dVV+kFb9W1cB+utJwZM1TzzkuhvfJj8cIY4QmtPi1Hs=; b=HFV8zqPfPElPqip9jR4f4F2czhlrGLGcu3iPx1oNrIlUtSYQ7W9LMZzmmhYKD5hR8mi4jj+5y nTuufHabrT+ab2MJYdT/voralQ/SvJ4CJMiMgtjEaDlvWFVocYqY1LiW5vxWesITNu+8KYjGRIV 9x3dEPpkUj3JxEiTF0KWRdM= Received: from mail.maildlp.com (unknown [172.19.162.144]) by canpmsgout01.his.huawei.com (SkyGuard) with ESMTPS id 4hLscj6MQnz1T4Fq; Fri, 14 Aug 2026 14:23:49 +0800 (CST) Received: from dggpemf500002.china.huawei.com (unknown [7.185.36.57]) by mail.maildlp.com (Postfix) with ESMTPS id EDC1C40538; Fri, 14 Aug 2026 14:33:42 +0800 (CST) Received: from [10.174.179.11] (10.174.179.11) by dggpemf500002.china.huawei.com (7.185.36.57) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 14 Aug 2026 14:33:42 +0800 Message-ID: <528a4c8f-f061-4879-9547-73eda8db77b0@huawei.com> Date: Fri, 14 Aug 2026 14:33:41 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 2/2] scsi: libsas: Add linkrate and sas_addr change detection in rediscover To: Xingui Yang , , , CC: , , , , References: <20260811040334.4184911-1-yangxingui@huawei.com> <20260811040334.4184911-3-yangxingui@huawei.com> From: Jason Yan In-Reply-To: <20260811040334.4184911-3-yangxingui@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems500002.china.huawei.com (7.221.188.17) To dggpemf500002.china.huawei.com (7.185.36.57) 在 2026/8/11 12:03, Xingui Yang 写道: > Introduce sas_dev_is_flutter() and sas_rediscover_ex_phy() to improve > flutter and device replace detection during rediscovery. > > sas_dev_is_flutter() calls sas_ex_phy_discover() before looking up the > child device via sas_ex_phy_to_dev(), ensuring the PHY state is always > updated and avoiding use-after-free since the child device pointer is > obtained after the sleeping SMP request completes. > > It adds validation for linkrate and sas_addr changes. When the SAS > address changes, phy->attached_sas_addr is restored to the original > address before returning false, so sas_unregister_devs_sas_addr() can > properly match and unregister the old device. The sas_addr check is > ordered before the linkrate check to avoid skipping the restoration > when both change simultaneously. > > sas_rediscover_ex_phy() uses the async discovery pattern > (sas_discover_event) instead of the synchronous sas_discover_new() to > ensure proper ordering between device unregistration and rediscovery, > avoiding sysfs_warn_dup() errors. > > Signed-off-by: Xingui Yang > Suggested-by: John Garry > --- > drivers/scsi/libsas/sas_expander.c | 83 +++++++++++++++++++++++++----- > 1 file changed, 69 insertions(+), 14 deletions(-) > > diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c > index a5c5327cd0dd..811c9eb4fef1 100644 > --- a/drivers/scsi/libsas/sas_expander.c > +++ b/drivers/scsi/libsas/sas_expander.c > @@ -1963,6 +1963,72 @@ static bool dev_type_flutter(enum sas_device_type new, enum sas_device_type old) > return false; > } > > +static void sas_rediscover_ex_phy(struct domain_device *dev, int phy_id, > + bool last) > +{ > + struct expander_device *ex = &dev->ex_dev; > + struct ex_phy *phy = &ex->ex_phy[phy_id]; > + > + phy->phy_change_count = -1; > + ex->ex_change_count = -1; > + sas_unregister_devs_sas_addr(dev, phy_id, last); > + sas_discover_event(dev->port, DISCE_REVALIDATE_DOMAIN); > +} > + > +static bool sas_dev_is_flutter(struct domain_device *dev, int phy_id, > + u8 *sas_addr, enum sas_device_type type) > +{ > + struct expander_device *ex = &dev->ex_dev; > + struct ex_phy *phy = &ex->ex_phy[phy_id]; > + struct domain_device *child_dev; > + char *action = ""; > + int res; > + > + if (SAS_ADDR(sas_addr) != SAS_ADDR(phy->attached_sas_addr) || > + !dev_type_flutter(type, phy->attached_dev_type)) > + return false; > + > + res = sas_ex_phy_discover(dev, phy_id); > + if (res) > + return false; > + > + child_dev = sas_ex_phy_to_dev(dev, phy_id); > + if (!child_dev) > + goto out; > + > + if (dev_is_sata(child_dev) && > + phy->attached_dev_type == SAS_SATA_PENDING) { > + action = ", needs recovery"; > + goto out; > + } > + > + if (SAS_ADDR(child_dev->sas_addr) != SAS_ADDR(phy->attached_sas_addr)) { > + pr_info("ex %016llx phy%02d sas_addr changed from %016llx to %016llx\n", > + SAS_ADDR(dev->sas_addr), phy_id, > + SAS_ADDR(child_dev->sas_addr), > + SAS_ADDR(phy->attached_sas_addr)); > + /* > + * Device unregistering relies on address matching. Restore > + * attached_sas_addr back to the original address so that the old > + * device can be unregistered later > + */ > + memcpy(phy->attached_sas_addr, child_dev->sas_addr, SAS_ADDR_SIZE); > + return false; > + } > + > + if (child_dev->linkrate != phy->linkrate) { > + pr_info("ex %016llx phy%02d linkrate changed from %d to %d\n", > + SAS_ADDR(dev->sas_addr), phy_id, > + child_dev->linkrate, phy->linkrate); > + return false; > + } > + > +out: > + pr_debug("ex %016llx phy%02d broadcast flutter%s\n", > + SAS_ADDR(dev->sas_addr), phy_id, action); > + return true; > +} > + > static int sas_rediscover_dev(struct domain_device *dev, int phy_id, > bool last, int sibling) > { > @@ -2016,27 +2082,16 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id, > if (res == 0) > sas_set_ex_phy(dev, phy_id, disc_resp); > goto out_free_resp; > - } else if (SAS_ADDR(sas_addr) == SAS_ADDR(phy->attached_sas_addr) && > - dev_type_flutter(type, phy->attached_dev_type)) { > - struct domain_device *ata_dev = sas_ex_to_ata(dev, phy_id); > - char *action = ""; > - > - sas_ex_phy_discover(dev, phy_id); > + } > > - if (ata_dev && phy->attached_dev_type == SAS_SATA_PENDING) > - action = ", needs recovery"; > - pr_debug("ex %016llx phy%02d broadcast flutter%s\n", > - SAS_ADDR(dev->sas_addr), phy_id, action); > + if (sas_dev_is_flutter(dev, phy_id, sas_addr, type)) > goto out_free_resp; > - } > > /* we always have to delete the old device when we went here */ Please remove this comment since you are not deleting the old device now. Thanks, Jason > pr_info("ex %016llx phy%02d replace %016llx\n", > SAS_ADDR(dev->sas_addr), phy_id, > SAS_ADDR(phy->attached_sas_addr)); > - sas_unregister_devs_sas_addr(dev, phy_id, last); > - > - res = sas_discover_new(dev, phy_id); > + sas_rediscover_ex_phy(dev, phy_id, last); > out_free_resp: > kfree(disc_resp); > return res;