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drivers/mtd: Fix device registration error

PATCH Superseded Aneesh Kumar K.V 2 participants 4 messages Feb 5, 2019 – Feb 6, 2019 Memory technology devices (MTD)

v1 of 2 Superseded Latest is v2 →

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Aneesh Kumar K.V

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#0 lore raw

PATCH 1/1 drivers/mtd: Fix device registration error

This change helps me to get multiple mtd device registered. Without this I get

sysfs: cannot create duplicate filename '/bus/nvmem/devices/flash0'

CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2-00557-g1ef20ef21f22 #13
Call Trace:
[c0000000b38e3220] [c000000000b58fe4] dump_stack+0xe8/0x164 (unreliable)
[c0000000b38e3270] [c0000000004cf074] sysfs_warn_dup+0x84/0xb0
[c0000000b38e32f0] [c0000000004cf6c4] sysfs_do_create_link_sd.isra.0+0x114/0x150
[c0000000b38e3340] [c000000000726a84] bus_add_device+0x94/0x1e0
[c0000000b38e33c0] [c0000000007218f0] device_add+0x4d0/0x830
[c0000000b38e3480] [c0000000009d54a8] nvmem_register.part.2+0x1c8/0xb30
[c0000000b38e3560] [c000000000834530] mtd_nvmem_add+0x90/0x120
[c0000000b38e3650] [c000000000835bc8] add_mtd_device+0x198/0x4e0
[c0000000b38e36f0] [c00000000083619c] mtd_device_parse_register+0x11c/0x280
[c0000000b38e3780] [c000000000840830] powernv_flash_probe+0x180/0x250
[c0000000b38e3820] [c00000000072c120] platform_drv_probe+0x60/0xf0
[c0000000b38e38a0] [c0000000007283c8] really_probe+0x138/0x4d0
[c0000000b38e3930] [c000000000728acc] driver_probe_device+0x13c/0x1b0
[c0000000b38e39b0] [c000000000728c7c] __driver_attach+0x13c/0x1c0
[c0000000b38e3a30] [c000000000725130] bus_for_each_dev+0xa0/0x120
[c0000000b38e3a90] [c000000000727b2c] driver_attach+0x2c/0x40
[c0000000b38e3ab0] [c0000000007270f8] bus_add_driver+0x228/0x360
[c0000000b38e3b40] [c00000000072a2e0] driver_register+0x90/0x1a0
[c0000000b38e3bb0] [c00000000072c020] __platform_driver_register+0x50/0x70
[c0000000b38e3bd0] [c00000000105c984] powernv_flash_driver_init+0x24/0x38
[c0000000b38e3bf0] [c000000000010904] do_one_initcall+0x84/0x464
[c0000000b38e3cd0] [c000000001004548] kernel_init_freeable+0x530/0x634
[c0000000b38e3db0] [c000000000011154] kernel_init+0x1c/0x168
[c0000000b38e3e20] [c00000000000bed4] ret_from_kernel_thread+0x5c/0x68

mtd mtd1: Failed to register NVMEM device

With the change we now have

/sys/bus/nvmem/devices# ls -al
total 0

drwxr-xr-x 2 root root 0 Feb  5 12:21 .
drwxr-xr-x 4 root root 0 Feb  5 12:21 ..
lrwxrwxrwx 1 root root 0 Feb  5 12:21 flash0 -> ../../../devices/platform/ibm,opal:flash@0/mtd/mtd0/flash0
lrwxrwxrwx 1 root root 0 Feb  5 12:21 flash1 -> ../../../devices/platform/ibm,opal:flash@1/mtd/mtd1/flash1
Signed-off-by Aneesh Kumar K.V <[email protected]>
---
 drivers/mtd/mtdcore.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
drivers/mtd/mtdcore.c +3 -2
index 999b705769a8..90035da3423c 100644
@@ -503,10 +503,11 @@ static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
 	return retlen == bytes ? 0 : -EIO;
 }
 
-static int mtd_nvmem_add(struct mtd_info *mtd)
+static int mtd_nvmem_add(struct mtd_info *mtd, int i)
 {
 	struct nvmem_config config = {};
 
+	config.id = i;
 	config.dev = &mtd->dev;
 	config.name = mtd->name;
 	config.owner = THIS_MODULE;

@@ -616,7 +617,7 @@ int add_mtd_device(struct mtd_info *mtd)
 		goto fail_added;
 
 	/* Add the nvmem provider */
-	error = mtd_nvmem_add(mtd);
+	error = mtd_nvmem_add(mtd, i);
 	if (error)
 		goto fail_nvmem_add;
Signature · 6 lines
2.20.1


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#1 lore raw

Hello Aneesh,

Quoted 52 lines · On Tue, 5 Feb 2019 14:35:47 +0530 "Aneesh Kumar K.V"…

This change helps me to get multiple mtd device registered. Without this I get

sysfs: cannot create duplicate filename '/bus/nvmem/devices/flash0'

CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2-00557-g1ef20ef21f22 #13
Call Trace:
[c0000000b38e3220] [c000000000b58fe4] dump_stack+0xe8/0x164 (unreliable)
[c0000000b38e3270] [c0000000004cf074] sysfs_warn_dup+0x84/0xb0
[c0000000b38e32f0] [c0000000004cf6c4] sysfs_do_create_link_sd.isra.0+0x114/0x150
[c0000000b38e3340] [c000000000726a84] bus_add_device+0x94/0x1e0
[c0000000b38e33c0] [c0000000007218f0] device_add+0x4d0/0x830
[c0000000b38e3480] [c0000000009d54a8] nvmem_register.part.2+0x1c8/0xb30
[c0000000b38e3560] [c000000000834530] mtd_nvmem_add+0x90/0x120
[c0000000b38e3650] [c000000000835bc8] add_mtd_device+0x198/0x4e0
[c0000000b38e36f0] [c00000000083619c] mtd_device_parse_register+0x11c/0x280
[c0000000b38e3780] [c000000000840830] powernv_flash_probe+0x180/0x250
[c0000000b38e3820] [c00000000072c120] platform_drv_probe+0x60/0xf0
[c0000000b38e38a0] [c0000000007283c8] really_probe+0x138/0x4d0
[c0000000b38e3930] [c000000000728acc] driver_probe_device+0x13c/0x1b0
[c0000000b38e39b0] [c000000000728c7c] __driver_attach+0x13c/0x1c0
[c0000000b38e3a30] [c000000000725130] bus_for_each_dev+0xa0/0x120
[c0000000b38e3a90] [c000000000727b2c] driver_attach+0x2c/0x40
[c0000000b38e3ab0] [c0000000007270f8] bus_add_driver+0x228/0x360
[c0000000b38e3b40] [c00000000072a2e0] driver_register+0x90/0x1a0
[c0000000b38e3bb0] [c00000000072c020] __platform_driver_register+0x50/0x70
[c0000000b38e3bd0] [c00000000105c984] powernv_flash_driver_init+0x24/0x38
[c0000000b38e3bf0] [c000000000010904] do_one_initcall+0x84/0x464
[c0000000b38e3cd0] [c000000001004548] kernel_init_freeable+0x530/0x634
[c0000000b38e3db0] [c000000000011154] kernel_init+0x1c/0x168
[c0000000b38e3e20] [c00000000000bed4] ret_from_kernel_thread+0x5c/0x68

mtd mtd1: Failed to register NVMEM device

With the change we now have

/sys/bus/nvmem/devices# ls -al
total 0

drwxr-xr-x 2 root root 0 Feb  5 12:21 .
drwxr-xr-x 4 root root 0 Feb  5 12:21 ..
lrwxrwxrwx 1 root root 0 Feb  5 12:21 flash0 -> ../../../devices/platform/ibm,opal:flash@0/mtd/mtd0/flash0
lrwxrwxrwx 1 root root 0 Feb  5 12:21 flash1 -> ../../../devices/platform/ibm,opal:flash@1/mtd/mtd1/flash1
Signed-off-by Aneesh Kumar K.V <[email protected]>
---
 drivers/mtd/mtdcore.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
drivers/mtd/mtdcore.c +0 -0
index 999b705769a8..90035da3423c 100644
@@ -503,10 +503,11 @@ static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
 	return retlen == bytes ? 0 : -EIO;

drivers/mtd/mtdcore.c static int mtd_nvmem_reg_read(void *priv, unsigned int offset, · line 512

Quoted 10 lines
drivers/mtd/mtdcore.c +2 -1
 }
 
-static int mtd_nvmem_add(struct mtd_info *mtd)
+static int mtd_nvmem_add(struct mtd_info *mtd, int i)
 {
 	struct nvmem_config config = {};
 
+	config.id = i;
 	config.dev = &mtd->dev;
 	config.name = mtd->name;

mtd->name should be unique in the first place, otherwise mtdparts parsing won't work (it's using mtd->name to match the device partitions should be applied to) and I guess there might be other issues. I know it's currently not enforced, but this kind of situation makes me realize we should enforce it.

So the right fix would be to have config.id = -1 and ensure mtd->name is unique at MTD registration time.

Back to your specific powernv case, using DT node name doesn't work, as the @<id> suffix is dropped, which means all your flash devices are named 'flash'.

drivers/mtd/mtdcore.c int add_mtd_device(struct mtd_info *mtd) · line 623

Quoted 10 lines
drivers/mtd/mtdcore.c +1 -1
 	config.owner = THIS_MODULE;

@@ -616,7 +617,7 @@ int add_mtd_device(struct mtd_info *mtd)
 		goto fail_added;
 
 	/* Add the nvmem provider */
-	error = mtd_nvmem_add(mtd);
+	error = mtd_nvmem_add(mtd, i);
 	if (error)
 		goto fail_nvmem_add;

Regards,

Boris

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author
#2 lore raw
Quoted 74 lines · Boris Brezillon

Hello Aneesh,

Quoted 52 lines · On Tue, 5 Feb 2019 14:35:47 +0530 "Aneesh Kumar K.V"…

This change helps me to get multiple mtd device registered. Without this I get

sysfs: cannot create duplicate filename '/bus/nvmem/devices/flash0'

CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2-00557-g1ef20ef21f22 #13
Call Trace:
[c0000000b38e3220] [c000000000b58fe4] dump_stack+0xe8/0x164 (unreliable)
[c0000000b38e3270] [c0000000004cf074] sysfs_warn_dup+0x84/0xb0
[c0000000b38e32f0] [c0000000004cf6c4] sysfs_do_create_link_sd.isra.0+0x114/0x150
[c0000000b38e3340] [c000000000726a84] bus_add_device+0x94/0x1e0
[c0000000b38e33c0] [c0000000007218f0] device_add+0x4d0/0x830
[c0000000b38e3480] [c0000000009d54a8] nvmem_register.part.2+0x1c8/0xb30
[c0000000b38e3560] [c000000000834530] mtd_nvmem_add+0x90/0x120
[c0000000b38e3650] [c000000000835bc8] add_mtd_device+0x198/0x4e0
[c0000000b38e36f0] [c00000000083619c] mtd_device_parse_register+0x11c/0x280
[c0000000b38e3780] [c000000000840830] powernv_flash_probe+0x180/0x250
[c0000000b38e3820] [c00000000072c120] platform_drv_probe+0x60/0xf0
[c0000000b38e38a0] [c0000000007283c8] really_probe+0x138/0x4d0
[c0000000b38e3930] [c000000000728acc] driver_probe_device+0x13c/0x1b0
[c0000000b38e39b0] [c000000000728c7c] __driver_attach+0x13c/0x1c0
[c0000000b38e3a30] [c000000000725130] bus_for_each_dev+0xa0/0x120
[c0000000b38e3a90] [c000000000727b2c] driver_attach+0x2c/0x40
[c0000000b38e3ab0] [c0000000007270f8] bus_add_driver+0x228/0x360
[c0000000b38e3b40] [c00000000072a2e0] driver_register+0x90/0x1a0
[c0000000b38e3bb0] [c00000000072c020] __platform_driver_register+0x50/0x70
[c0000000b38e3bd0] [c00000000105c984] powernv_flash_driver_init+0x24/0x38
[c0000000b38e3bf0] [c000000000010904] do_one_initcall+0x84/0x464
[c0000000b38e3cd0] [c000000001004548] kernel_init_freeable+0x530/0x634
[c0000000b38e3db0] [c000000000011154] kernel_init+0x1c/0x168
[c0000000b38e3e20] [c00000000000bed4] ret_from_kernel_thread+0x5c/0x68

mtd mtd1: Failed to register NVMEM device

With the change we now have

/sys/bus/nvmem/devices# ls -al
total 0

drwxr-xr-x 2 root root 0 Feb  5 12:21 .
drwxr-xr-x 4 root root 0 Feb  5 12:21 ..
lrwxrwxrwx 1 root root 0 Feb  5 12:21 flash0 -> ../../../devices/platform/ibm,opal:flash@0/mtd/mtd0/flash0
lrwxrwxrwx 1 root root 0 Feb  5 12:21 flash1 -> ../../../devices/platform/ibm,opal:flash@1/mtd/mtd1/flash1
Signed-off-by Aneesh Kumar K.V <[email protected]>
---
 drivers/mtd/mtdcore.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
drivers/mtd/mtdcore.c +0 -0
index 999b705769a8..90035da3423c 100644
@@ -503,10 +503,11 @@ static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
 	return retlen == bytes ? 0 : -EIO;

drivers/mtd/mtdcore.c static int mtd_nvmem_reg_read(void *priv, unsigned int offset, · line 512

Quoted 10 lines
drivers/mtd/mtdcore.c +2 -1
 }
 
-static int mtd_nvmem_add(struct mtd_info *mtd)
+static int mtd_nvmem_add(struct mtd_info *mtd, int i)
 {
 	struct nvmem_config config = {};
 
+	config.id = i;
 	config.dev = &mtd->dev;
 	config.name = mtd->name;

mtd->name should be unique in the first place, otherwise mtdparts parsing won't work (it's using mtd->name to match the device partitions should be applied to) and I guess there might be other issues. I know it's currently not enforced, but this kind of situation makes me realize we should enforce it.

Quoted 6 lines

So the right fix would be to have config.id = -1 and ensure mtd->name is unique at MTD registration time.

Back to your specific powernv case, using DT node name doesn't work, as the @<id> suffix is dropped, which means all your flash devices are named 'flash'.

How about

	mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);

That gives me flash@0 name. Is that ok?

-aneesh

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#3 lore raw
Quoted 79 lines · On Wed, 06 Feb 2019 10:22:59 +0530 "Aneesh Kumar K.V"…
Quoted 77 lines · Boris Brezillon

Hello Aneesh,

Quoted 52 lines · On Tue, 5 Feb 2019 14:35:47 +0530 "Aneesh Kumar K.V"…

This change helps me to get multiple mtd device registered. Without this I get

sysfs: cannot create duplicate filename '/bus/nvmem/devices/flash0'

CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2-00557-g1ef20ef21f22 #13
Call Trace:
[c0000000b38e3220] [c000000000b58fe4] dump_stack+0xe8/0x164 (unreliable)
[c0000000b38e3270] [c0000000004cf074] sysfs_warn_dup+0x84/0xb0
[c0000000b38e32f0] [c0000000004cf6c4] sysfs_do_create_link_sd.isra.0+0x114/0x150
[c0000000b38e3340] [c000000000726a84] bus_add_device+0x94/0x1e0
[c0000000b38e33c0] [c0000000007218f0] device_add+0x4d0/0x830
[c0000000b38e3480] [c0000000009d54a8] nvmem_register.part.2+0x1c8/0xb30
[c0000000b38e3560] [c000000000834530] mtd_nvmem_add+0x90/0x120
[c0000000b38e3650] [c000000000835bc8] add_mtd_device+0x198/0x4e0
[c0000000b38e36f0] [c00000000083619c] mtd_device_parse_register+0x11c/0x280
[c0000000b38e3780] [c000000000840830] powernv_flash_probe+0x180/0x250
[c0000000b38e3820] [c00000000072c120] platform_drv_probe+0x60/0xf0
[c0000000b38e38a0] [c0000000007283c8] really_probe+0x138/0x4d0
[c0000000b38e3930] [c000000000728acc] driver_probe_device+0x13c/0x1b0
[c0000000b38e39b0] [c000000000728c7c] __driver_attach+0x13c/0x1c0
[c0000000b38e3a30] [c000000000725130] bus_for_each_dev+0xa0/0x120
[c0000000b38e3a90] [c000000000727b2c] driver_attach+0x2c/0x40
[c0000000b38e3ab0] [c0000000007270f8] bus_add_driver+0x228/0x360
[c0000000b38e3b40] [c00000000072a2e0] driver_register+0x90/0x1a0
[c0000000b38e3bb0] [c00000000072c020] __platform_driver_register+0x50/0x70
[c0000000b38e3bd0] [c00000000105c984] powernv_flash_driver_init+0x24/0x38
[c0000000b38e3bf0] [c000000000010904] do_one_initcall+0x84/0x464
[c0000000b38e3cd0] [c000000001004548] kernel_init_freeable+0x530/0x634
[c0000000b38e3db0] [c000000000011154] kernel_init+0x1c/0x168
[c0000000b38e3e20] [c00000000000bed4] ret_from_kernel_thread+0x5c/0x68

mtd mtd1: Failed to register NVMEM device

With the change we now have

/sys/bus/nvmem/devices# ls -al
total 0

drwxr-xr-x 2 root root 0 Feb  5 12:21 .
drwxr-xr-x 4 root root 0 Feb  5 12:21 ..
lrwxrwxrwx 1 root root 0 Feb  5 12:21 flash0 -> ../../../devices/platform/ibm,opal:flash@0/mtd/mtd0/flash0
lrwxrwxrwx 1 root root 0 Feb  5 12:21 flash1 -> ../../../devices/platform/ibm,opal:flash@1/mtd/mtd1/flash1
Signed-off-by Aneesh Kumar K.V <[email protected]>
---
 drivers/mtd/mtdcore.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
drivers/mtd/mtdcore.c +0 -0
index 999b705769a8..90035da3423c 100644
@@ -503,10 +503,11 @@ static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
 	return retlen == bytes ? 0 : -EIO;

drivers/mtd/mtdcore.c static int mtd_nvmem_reg_read(void *priv, unsigned int offset, · line 512

Quoted 10 lines
drivers/mtd/mtdcore.c +2 -1
 }
 
-static int mtd_nvmem_add(struct mtd_info *mtd)
+static int mtd_nvmem_add(struct mtd_info *mtd, int i)
 {
 	struct nvmem_config config = {};
 
+	config.id = i;
 	config.dev = &mtd->dev;
 	config.name = mtd->name;

mtd->name should be unique in the first place, otherwise mtdparts parsing won't work (it's using mtd->name to match the device partitions should be applied to) and I guess there might be other issues. I know it's currently not enforced, but this kind of situation makes me realize we should enforce it.

So the right fix would be to have config.id = -1 and ensure mtd->name is unique at MTD registration time.

Quoted 8 lines
Quoted 3 lines

Back to your specific powernv case, using DT node name doesn't work, as the @<id> suffix is dropped, which means all your flash devices are named 'flash'.

How about

	mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);

That gives me flash@0 name. Is that ok?

It should work.

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/