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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Vadim Pasternak <vadimp@mellanox.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 15/56] platform/x86: mlx-platform: Fix parent device in i2c-mux-reg device registration
Date:   Mon,  8 Jul 2019 17:13:07 +0200
Message-Id: <20190708150519.851598649@linuxfoundation.org>
In-Reply-To: <20190708150514.376317156@linuxfoundation.org>
References: <20190708150514.376317156@linuxfoundation.org>
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[ Upstream commit 160da20b254dd4bfc5828f12c208fa831ad4be6c ]

Fix the issue found while running kernel with the option
CONFIG_DEBUG_TEST_DRIVER_REMOVE.
Driver 'mlx-platform' registers 'i2c_mlxcpld' device and then registers
few underlying 'i2c-mux-reg' devices:
	priv->pdev_i2c = platform_device_register_simple("i2c_mlxcpld", nr,
							 NULL, 0);
	...
	for (i = 0; i < ARRAY_SIZE(mlxplat_mux_data); i++) {
		priv->pdev_mux[i] = platform_device_register_resndata(
						&mlxplat_dev->dev,
						"i2c-mux-reg", i, NULL,
						0, &mlxplat_mux_data[i],
						sizeof(mlxplat_mux_data[i]));

But actual parent of "i2c-mux-reg" device is priv->pdev_i2c->dev and
not mlxplat_dev->dev.
Patch fixes parent device parameter in a call to
platform_device_register_resndata() for "i2c-mux-reg".

It solves the race during initialization flow while 'i2c_mlxcpld.1' is
removing after probe, while 'i2c-mux-reg.0' is still in probing flow:
'i2c_mlxcpld.1'	flow:	probe -> remove -> probe.
'i2c-mux-reg.0'	flow:		  probe -> ...

[   12:621096] Registering platform device 'i2c_mlxcpld.1'. Parent at platform
[   12:621117] device: 'i2c_mlxcpld.1': device_add
[   12:621155] bus: 'platform': add device i2c_mlxcpld.1
[   12:621384] Registering platform device 'i2c-mux-reg.0'. Parent at mlxplat
[   12:621395] device: 'i2c-mux-reg.0': device_add
[   12:621425] bus: 'platform': add device i2c-mux-reg.0
[   12:621806] Registering platform device 'i2c-mux-reg.1'. Parent at mlxplat
[   12:621828] device: 'i2c-mux-reg.1': device_add
[   12:621892] bus: 'platform': add device i2c-mux-reg.1
[   12:621906] bus: 'platform': add driver i2c_mlxcpld
[   12:621996] bus: 'platform': driver_probe_device: matched device i2c_mlxcpld.1 with driver i2c_mlxcpld
[   12:622003] bus: 'platform': really_probe: probing driver i2c_mlxcpld with device i2c_mlxcpld.1
[   12:622100] i2c_mlxcpld i2c_mlxcpld.1: no default pinctrl state
[   12:622293] device: 'i2c-1': device_add
[   12:627280] bus: 'i2c': add device i2c-1
[   12:627692] device: 'i2c-1': device_add
[   12.629639] bus: 'platform': add driver i2c-mux-reg
[   12.629718] bus: 'platform': driver_probe_device: matched device i2c-mux-reg.0 with driver i2c-mux-reg
[   12.629723] bus: 'platform': really_probe: probing driver i2c-mux-reg with device i2c-mux-reg.0
[   12.629818] i2c-mux-reg i2c-mux-reg.0: no default pinctrl state
[   12.629981] platform i2c-mux-reg.0: Driver i2c-mux-reg requests probe deferral
[   12.629986] platform i2c-mux-reg.0: Added to deferred list
[   12.629992] bus: 'platform': driver_probe_device: matched device i2c-mux-reg.1 with driver i2c-mux-reg
[   12.629997] bus: 'platform': really_probe: probing driver i2c-mux-reg with device i2c-mux-reg.1
[   12.630091] i2c-mux-reg i2c-mux-reg.1: no default pinctrl state
[   12.630247] platform i2c-mux-reg.1: Driver i2c-mux-reg requests probe deferral
[   12.630252] platform i2c-mux-reg.1: Added to deferred list
[   12.640892] devices_kset: Moving i2c-mux-reg.0 to end of list
[   12.640900] platform i2c-mux-reg.0: Retrying from deferred list
[   12.640911] bus: 'platform': driver_probe_device: matched device i2c-mux-reg.0 with driver i2c-mux-reg
[   12.640919] bus: 'platform': really_probe: probing driver i2c-mux-reg with device i2c-mux-reg.0
[   12.640999] i2c-mux-reg i2c-mux-reg.0: no default pinctrl state
[   12.641177] platform i2c-mux-reg.0: Driver i2c-mux-reg requests probe deferral
[   12.641187] platform i2c-mux-reg.0: Added to deferred list
[   12.641198] devices_kset: Moving i2c-mux-reg.1 to end of list
[   12.641219] platform i2c-mux-reg.1: Retrying from deferred list
[   12.641237] bus: 'platform': driver_probe_device: matched device i2c-mux-reg.1 with driver i2c-mux-reg
[   12.641247] bus: 'platform': really_probe: probing driver i2c-mux-reg with device i2c-mux-reg.1
[   12.641331] i2c-mux-reg i2c-mux-reg.1: no default pinctrl state
[   12.641465] platform i2c-mux-reg.1: Driver i2c-mux-reg requests probe deferral
[   12.641469] platform i2c-mux-reg.1: Added to deferred list
[   12.646427] device: 'i2c-1': device_add
[   12.646647] bus: 'i2c': add device i2c-1
[   12.647104] device: 'i2c-1': device_add
[   12.669231] devices_kset: Moving i2c-mux-reg.0 to end of list
[   12.669240] platform i2c-mux-reg.0: Retrying from deferred list
[   12.669258] bus: 'platform': driver_probe_device: matched device i2c-mux-reg.0 with driver i2c-mux-reg
[   12.669263] bus: 'platform': really_probe: probing driver i2c-mux-reg with device i2c-mux-reg.0
[   12.669343] i2c-mux-reg i2c-mux-reg.0: no default pinctrl state
[   12.669585] device: 'i2c-2': device_add
[   12.669795] bus: 'i2c': add device i2c-2
[   12.670201] device: 'i2c-2': device_add
[   12.671427] i2c i2c-1: Added multiplexed i2c bus 2
[   12.671514] device: 'i2c-3': device_add
[   12.671724] bus: 'i2c': add device i2c-3
[   12.672136] device: 'i2c-3': device_add
[   12.673378] i2c i2c-1: Added multiplexed i2c bus 3
[   12.673472] device: 'i2c-4': device_add
[   12.673676] bus: 'i2c': add device i2c-4
[   12.674060] device: 'i2c-4': device_add
[   12.675861] i2c i2c-1: Added multiplexed i2c bus 4
[   12.675941] device: 'i2c-5': device_add
[   12.676150] bus: 'i2c': add device i2c-5
[   12.676550] device: 'i2c-5': device_add
[   12.678103] i2c i2c-1: Added multiplexed i2c bus 5
[   12.678193] device: 'i2c-6': device_add
[   12.678395] bus: 'i2c': add device i2c-6
[   12.678774] device: 'i2c-6': device_add
[   12.679969] i2c i2c-1: Added multiplexed i2c bus 6
[   12.680065] device: 'i2c-7': device_add
[   12.680275] bus: 'i2c': add device i2c-7
[   12.680913] device: 'i2c-7': device_add
[   12.682506] i2c i2c-1: Added multiplexed i2c bus 7
[   12.682600] device: 'i2c-8': device_add
[   12.682808] bus: 'i2c': add device i2c-8
[   12.683189] device: 'i2c-8': device_add
[   12.683907] device: 'i2c-1': device_unregister
[   12.683945] device: 'i2c-1': device_unregister
[   12.684387] device: 'i2c-1': device_create_release
[   12.684536] bus: 'i2c': remove device i2c-1
[   12.686019] i2c i2c-8: Failed to create compatibility class link
[   12.686086] ------------[ cut here ]------------
[   12.686087] can't create symlink to mux device
[   12.686224] Workqueue: events deferred_probe_work_func
[   12.686135] WARNING: CPU: 7 PID: 436 at drivers/i2c/i2c-mux.c:416 i2c_mux_add_adapter+0x729/0x7d0 [i2c_mux]
[   12.686232] RIP: 0010:i2c_mux_add_adapter+0x729/0x7d0 [i2c_mux]
[   0x190/0x190 [i2c_mux]
[   12.686300]  ? i2c_mux_alloc+0xac/0x110 [i2c_mux]
[   12.686306]  ? i2c_mux_reg_set+0x200/0x200 [i2c_mux_reg]
[   12.686313]  i2c_mux_reg_probe+0x22c/0x731 [i2c_mux_reg]
[   12.686322]  ? i2c_mux_reg_deselect+0x60/0x60 [i2c_mux_reg]
[   12.686346]  platform_drv_probe+0xa8/0x110
[   12.686351]  really_probe+0x185/0x720
[   12.686358]  driver_probe_device+0xdf/0x1f0
...
[   12.686522] i2c i2c-1: Added multiplexed i2c bus 8
[   12.686621] device: 'i2c-9': device_add
[   12.686626] kobject_add_internal failed for i2c-9 (error: -2 parent: i2c-1)
[   12.694729] i2c-core: adapter 'i2c-1-mux (chan_id 8)': can't register device (-2)
[   12.705726] i2c i2c-1: failed to add mux-adapter 8 as bus 9 (error=-2)
[   12.714494] device: 'i2c-8': device_unregister
[   12.714537] device: 'i2c-8': device_unregister

Fixes: 6613d18e9038 ("platform/x86: mlx-platform: Move module from arch/x86")
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/x86/mlx-platform.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/mlx-platform.c b/drivers/platform/x86/mlx-platform.c
index 4f3de2a8c4df..9aced80f31a2 100644
--- a/drivers/platform/x86/mlx-platform.c
+++ b/drivers/platform/x86/mlx-platform.c
@@ -318,7 +318,7 @@ static int __init mlxplat_init(void)
 
 	for (i = 0; i < ARRAY_SIZE(mlxplat_mux_data); i++) {
 		priv->pdev_mux[i] = platform_device_register_resndata(
-						&mlxplat_dev->dev,
+						&priv->pdev_i2c->dev,
 						"i2c-mux-reg", i, NULL,
 						0, &mlxplat_mux_data[i],
 						sizeof(mlxplat_mux_data[i]));
-- 
2.20.1