From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794323478; b=mjUtVe4QUcwLZr96zKUlbzPpC+EevHdtTXPthJzGm69jkkjMx66E+c340jrgzmnwBoon xuxTpBzgCVYyjjgeP+hbaH9SUyHrmCqByDoK2itWXeUUxV+3abrPHCfEKaBaUqlb8NIyM znqiBu3xeEFM8mc+j3ScBP1E9JmTP4Bo8B7Ger1W3DD4hOyOPnJnlfcT2IutUb+NM+N2h tQ721DjPGOp1ErnR9392RE8hmjSjRUnOBs0+UBLCZqqOBUzXJ0P9imlbD1DjGYEIfcX8S hB9aScUdmBXOWv0tL12GbbMpgSI7sHSK2oJy6xW3gfagqsRKmcYTXEKGiyPR6pj1/4w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794323478; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=sin9+RXShimd6JYHdQjFZ3KA5rJFaUHE/vaPbVsVQyw=; b=J9JxH0VCx5xQSmhaUxQDecIvdCaueI39XCmYWzdUcHUChaMSsWlMPTtkCGJLsGy4THml lI34yT2SxpHYnYxOA76iAm2Vnr/Pj4fEoZ4WrE0/4EGQfuWMxr29DcG0yj6nl+FE39q2A TVbWuTviFlz/JT0E7OI6z6idTlyi7j+pJSK6jxXUrCithEwcNpFIMiwvmc8BfRi+2GB4f iBE4jcnPGpf+uuvEI3LSv5BxWvFaEOWnHdDT2BeZJOJhpysO4+ThiAKK7y+Fq2mxzaxF+ JvCphFWK8/bvUAy9z5KHcaYDacr6k9AAwbD7PFXMQXjS2nT80Ez+aYGqTbidAR8U5/w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=TvCAM9hp; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 795C2606A321 for ; Tue, 10 Nov 2026 15:11:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=TvCAM9hp Received: by smtp.kernel.org (Postfix) with ESMTPSA id 333061F008AB; Tue, 10 Nov 2026 15:11:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794323478; bh=sin9+RXShimd6JYHdQjFZ3KA5rJFaUHE/vaPbVsVQyw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TvCAM9hpO6AaESUUlQ6t2lgt+Iy4PXZF3Q+7cXRAFkDz2K/uwvJzkxg2N7nWMoIeR iKRal1RSOKKTml3fObhsR6DmubYCbmQ3SgExU8momCjmsBPJ3LoG2e1+FMha3L8JZo R0kdb/904JDmDh5Z+WAG8e5wGxnCU7wGmmzfdR9pFPHe6RtwAiNa+V1Dj4GcnxOkdp ZZToEk7HH8nsHbfcjNC6OBnhBUbo/x+U7EjCSZXgq4q93X2TjvBrI7+v4oOthK36GR jxK7dp/zPSnHAzxFYWlrexz40UEt7/RROfu+Dh37ljh3zT06gTTpNTPdaEuDopGM1r DneqfHXYAf/bQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Dan Williams , Dave Jiang , Jonathan Cameron , Terry Bowman , Sasha Levin Subject: [PATCH 6.18.y 1/2] cxl/port: Cleanup handling of the nr_dports 0 -> 1 transition Date: Tue, 10 Nov 2026 10:11:13 -0500 Message-ID: <20261110151026.2046421-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107051004-failed-6.18-019560d23450@kernel.org> References: <20261107051004-failed-6.18-019560d23450@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Dan Williams [ Upstream commit 47fec713d97fb6b823026f723435b58af541bd8d ] There are multiple setup actions that can occur for a switch port after it is known that it has at least one active downstream link. That work is currently split between __devm_cxl_add_dport(), the add_dport() helper, and cxl_port_add_dport() where decoder setup occurs. Clean this up by moving all @dport object setup responsibilities into add_dport() and all port effects into cxl_port_add_dport(). add_dport() handles taking a reference on @dport->dport_dev, and cxl_port_add_dport() grows the awareness to setup the port component registers. This removes an awkward open-coded xa_erase() from the middle of __devm_cxl_add_dport() and instead tasks cxl_port_add_dport() with calling the common @dport destruction path if anything goes wrong. After this @port->nr_dports is always the count of @dports in the @port->dports xarray, and cxl_dport_remove() is symmetric with add_dport(). With ->nr_dports now reliably tracking the number of dports the use of ida_is_empty() can be dropped. Recall that the ida is only cleared on "release" of decoder objects, and release can be arbitrarily delayed past unregistration. Lastly port->component_reg_phys is no longer reset to CXL_RESOURCE_NONE post setup, no reason is seen to carry that forward. Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Tested-by: Terry Bowman Signed-off-by: Dan Williams Link: https://patch.msgid.link/20260131000403.2135324-2-dan.j.williams@intel.com Signed-off-by: Dave Jiang Stable-dep-of: 019560d23450 ("cxl/port: Clear cached dport pointers when a dport is removed") Signed-off-by: Sasha Levin --- drivers/cxl/core/port.c | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-) diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index 599aa9d9eddca..a7d3497f82c05 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -1073,11 +1073,15 @@ static int add_dport(struct cxl_port *port, struct cxl_dport *dport) return -EBUSY; } + /* Arrange for dport_dev to be valid through remove_dport() */ + struct device *dev __free(put_device) = get_device(dport->dport_dev); + rc = xa_insert(&port->dports, (unsigned long)dport->dport_dev, dport, GFP_KERNEL); if (rc) return rc; + retain_and_null_ptr(dev); port->nr_dports++; return 0; } @@ -1106,6 +1110,7 @@ static void cxl_dport_remove(void *data) struct cxl_dport *dport = data; struct cxl_port *port = dport->port; + port->nr_dports--; xa_erase(&port->dports, (unsigned long) dport->dport_dev); put_device(dport->dport_dev); } @@ -1188,21 +1193,6 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev, if (rc) return ERR_PTR(rc); - /* - * Setup port register if this is the first dport showed up. Having - * a dport also means that there is at least 1 active link. - */ - if (port->nr_dports == 1 && - port->component_reg_phys != CXL_RESOURCE_NONE) { - rc = cxl_port_setup_regs(port, port->component_reg_phys); - if (rc) { - xa_erase(&port->dports, (unsigned long)dport->dport_dev); - return ERR_PTR(rc); - } - port->component_reg_phys = CXL_RESOURCE_NONE; - } - - get_device(dport_dev); rc = devm_add_action_or_reset(host, cxl_dport_remove, dport); if (rc) return ERR_PTR(rc); @@ -1629,7 +1619,16 @@ static struct cxl_dport *cxl_port_add_dport(struct cxl_port *port, cxl_switch_parse_cdat(new_dport); - if (ida_is_empty(&port->decoder_ida)) { + if (port->nr_dports == 1) { + /* + * Some host bridges are known to not have component regsisters + * available until a root port has trained CXL. Perform that + * setup now. + */ + rc = cxl_port_setup_regs(port, port->component_reg_phys); + if (rc) + return ERR_PTR(rc); + rc = devm_cxl_switch_port_decoders_setup(port); if (rc) return ERR_PTR(rc); -- 2.53.0