[PATCH 1/2] ubi: Expose interface for detailed erase counters

[PATCH 1/2] ubi: Expose interface for detailed erase counters

[Rickard Andersson]

Using the ioctl command 'UBI_IOCECNFO' user space can obtain
detailed erase counter information of all blocks of a device.

Signed-off-by: Rickard Andersson <rickard.andersson@axis.com>
---
 include/uapi/mtd/ubi-user.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/include/uapi/mtd/ubi-user.h b/include/uapi/mtd/ubi-user.h
index e1571603175e..667680e44ed4 100644
--- a/include/uapi/mtd/ubi-user.h
+++ b/include/uapi/mtd/ubi-user.h
@@ -175,6 +175,8 @@
 #define UBI_IOCRPEB _IOW(UBI_IOC_MAGIC, 4, __s32)
 /* Force scrubbing on the specified PEB */
 #define UBI_IOCSPEB _IOW(UBI_IOC_MAGIC, 5, __s32)
+/* Read detailed device erase counter information */
+#define UBI_IOCECNFO _IOWR(UBI_IOC_MAGIC, 6, struct ubi_ecinfo_req)
 
 /* ioctl commands of the UBI control character device */
 
@@ -470,4 +472,27 @@ struct ubi_blkcreate_req {
 	__s8  padding[128];
 }  __packed;
 
+/**
+ * struct ubi_ecinfo_req - a data structure used in UBI device erase count
+ * information requests and responses.
+ *
+ * @start_ec_req: first erase counter block in range to read
+ * @end_ec_req: last erase counter block in the half-open range
+ * @end_ec_res: last erase counter block that was actually read
+ * @erase_counters: array of erase counter values
+ * @padding: reserved for future, not used, has to be zeroed
+ *
+ * Erase counters are read in range @start_ec_req to @end_ec_req. Range is half-open
+ * i.e erase counter of end_ec_req is not actually included.
+ * The read erase counters are placed in @erase_counters. If a block is bad or if the
+ * erase counter is unknown the value of the block will be set to -1.
+ */
+struct ubi_ecinfo_req {
+	__s32 start_ec_req;
+	__s32 end_ec_req;
+	__s32 end_ec_res;
+	__s32 erase_counters[1000];
+	__s8  padding[84];
+}  __packed;
+
 #endif /* __UBI_USER_H__ */
-- 
2.30.2


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[PATCH 2/2] ubi: Implement ioctl for detailed erase counters

[Rickard Andersson]

Currently, only "max_ec" can be read from sysfs, which provides a
limited view of the flash device’s wear. In certain cases, such as
bugs in the wear-leveling algorithm, specific blocks can be worn down
more than others, resulting in uneven wear distribution. Providing
detailed erase counter values give a better understanding of the
overall flash wear.
There exists more detailed info in debugfs, but this information is
only available for debug builds.

Signed-off-by: Rickard Andersson <rickard.andersson@axis.com>
---
 drivers/mtd/ubi/cdev.c | 86 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 0d8f04cf03c5..4af99ddbba66 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -828,6 +828,86 @@ static int rename_volumes(struct ubi_device *ubi,
 	return err;
 }
 
+
+static int ubi_get_ec_info(struct ubi_device *ubi, void __user *argp)
+{
+	struct ubi_ecinfo_req *req;
+	struct ubi_wl_entry *wl;
+	int peb;
+	int end_peb;
+	int i;
+	int err = 0;
+
+	req = kzalloc(sizeof(struct ubi_ecinfo_req), GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	/* Copy just the input arguments */
+	err = copy_from_user(req, argp, sizeof(struct ubi_ecinfo_req) -
+			     offsetof(struct ubi_ecinfo_req, end_ec_res));
+	if (err) {
+		err = -EFAULT;
+		goto out_free;
+	}
+
+	/* Make sure that start value is less or equal to end value */
+	if (req->start_ec_req > req->end_ec_req) {
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	/* Check input argument start value */
+	if ((req->start_ec_req < 0 || req->start_ec_req >= ubi->peb_count)) {
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	/* Check if end value is less than 0 */
+	if (req->end_ec_req < 0) {
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	end_peb = req->end_ec_req;
+
+	/* Control end value */
+	if (end_peb > ubi->peb_count)
+		end_peb = ubi->peb_count;
+
+	/* Check that we do not overwrite our working memory */
+	if (end_peb > (ARRAY_SIZE(req->erase_counters) + req->start_ec_req))
+		end_peb = ARRAY_SIZE(req->erase_counters) + req->start_ec_req;
+
+	i = 0;
+	for (peb = req->start_ec_req; peb < end_peb; i++, peb++) {
+
+		if (ubi_io_is_bad(ubi, peb)) {
+			req->erase_counters[i] = UBI_UNKNOWN;
+			continue;
+		}
+
+		spin_lock(&ubi->wl_lock);
+
+		wl = ubi->lookuptbl[peb];
+		if (wl)
+			req->erase_counters[i] = wl->ec;
+		else
+			req->erase_counters[i] = UBI_UNKNOWN;
+
+		spin_unlock(&ubi->wl_lock);
+	}
+
+	/* Return last read peb */
+	req->end_ec_res = end_peb - 1;
+
+	if (copy_to_user(argp, req, sizeof(struct ubi_ecinfo_req)))
+		err = -EFAULT;
+
+out_free:
+	kfree(req);
+	return err;
+}
+
 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 			   unsigned long arg)
 {
@@ -991,6 +1071,12 @@ static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 		break;
 	}
 
+	case UBI_IOCECNFO:
+	{
+		err = ubi_get_ec_info(ubi, argp);
+		break;
+	}
+
 	default:
 		err = -ENOTTY;
 		break;
-- 
2.30.2


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Re: [PATCH 1/2] ubi: Expose interface for detailed erase counters

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "Rickard X Andersson" <rickard.andersson@axis.com>
> +/**
> + * struct ubi_ecinfo_req - a data structure used in UBI device erase count
> + * information requests and responses.
> + *
> + * @start_ec_req: first erase counter block in range to read
> + * @end_ec_req: last erase counter block in the half-open range
> + * @end_ec_res: last erase counter block that was actually read
> + * @erase_counters: array of erase counter values
> + * @padding: reserved for future, not used, has to be zeroed
> + *
> + * Erase counters are read in range @start_ec_req to @end_ec_req. Range is
> half-open
> + * i.e erase counter of end_ec_req is not actually included.
> + * The read erase counters are placed in @erase_counters. If a block is bad or
> if the
> + * erase counter is unknown the value of the block will be set to -1.
> + */
> +struct ubi_ecinfo_req {
> +	__s32 start_ec_req;
> +	__s32 end_ec_req;
> +	__s32 end_ec_res;
> +	__s32 erase_counters[1000];

There is no need to have a limited number. Just use a flexible array.
If userspace asks for more entries than the provided buffer can hold, __put_user()
will fail anyways.

Have a look at fibmap, I think you can the model the API the same way.

Thanks,
//richard

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Re: [PATCH 1/2] ubi: Expose interface for detailed erase counters

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "richard" <richard@nod.at>
> An: "Rickard X Andersson" <rickard.andersson@axis.com>
> CC: "chengzhihao1" <chengzhihao1@huawei.com>, "linux-mtd" <linux-mtd@lists.infradead.org>, "rickard314 andersson"
> <rickard314.andersson@gmail.com>, "kernel" <kernel@axis.com>
> Gesendet: Montag, 25. November 2024 16:44:54
> Betreff: Re: [PATCH 1/2] ubi: Expose interface for detailed erase counters

> ----- Ursprüngliche Mail -----
>> Von: "Rickard X Andersson" <rickard.andersson@axis.com>
>> +/**
>> + * struct ubi_ecinfo_req - a data structure used in UBI device erase count
>> + * information requests and responses.
>> + *
>> + * @start_ec_req: first erase counter block in range to read
>> + * @end_ec_req: last erase counter block in the half-open range
>> + * @end_ec_res: last erase counter block that was actually read
>> + * @erase_counters: array of erase counter values
>> + * @padding: reserved for future, not used, has to be zeroed
>> + *
>> + * Erase counters are read in range @start_ec_req to @end_ec_req. Range is
>> half-open
>> + * i.e erase counter of end_ec_req is not actually included.
>> + * The read erase counters are placed in @erase_counters. If a block is bad or
>> if the
>> + * erase counter is unknown the value of the block will be set to -1.
>> + */
>> +struct ubi_ecinfo_req {
>> +	__s32 start_ec_req;
>> +	__s32 end_ec_req;
>> +	__s32 end_ec_res;
>> +	__s32 erase_counters[1000];
> 
> There is no need to have a limited number. Just use a flexible array.
> If userspace asks for more entries than the provided buffer can hold,
> __put_user()
> will fail anyways.
> 
> Have a look at fibmap, I think you can the model the API the same way.

*fiemap
 
Thanks,
//richard

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Re: [PATCH 1/2] ubi: Expose interface for detailed erase counters

[Zhihao Cheng]

在 2024/11/25 21:48, Rickard Andersson 写道:
> Using the ioctl command 'UBI_IOCECNFO' user space can obtain
> detailed erase counter information of all blocks of a device.
> 
> Signed-off-by: Rickard Andersson <rickard.andersson@axis.com>
> ---
>   include/uapi/mtd/ubi-user.h | 25 +++++++++++++++++++++++++
>   1 file changed, 25 insertions(+)
> 
> diff --git a/include/uapi/mtd/ubi-user.h b/include/uapi/mtd/ubi-user.h
> index e1571603175e..667680e44ed4 100644
> --- a/include/uapi/mtd/ubi-user.h
> +++ b/include/uapi/mtd/ubi-user.h
> @@ -175,6 +175,8 @@
>   #define UBI_IOCRPEB _IOW(UBI_IOC_MAGIC, 4, __s32)
>   /* Force scrubbing on the specified PEB */
>   #define UBI_IOCSPEB _IOW(UBI_IOC_MAGIC, 5, __s32)
> +/* Read detailed device erase counter information */
> +#define UBI_IOCECNFO _IOWR(UBI_IOC_MAGIC, 6, struct ubi_ecinfo_req)
>   
>   /* ioctl commands of the UBI control character device */
>   
> @@ -470,4 +472,27 @@ struct ubi_blkcreate_req {
>   	__s8  padding[128];
>   }  __packed;
>   
> +/**
> + * struct ubi_ecinfo_req - a data structure used in UBI device erase count
> + * information requests and responses.
> + *
> + * @start_ec_req: first erase counter block in range to read
> + * @end_ec_req: last erase counter block in the half-open range
> + * @end_ec_res: last erase counter block that was actually read
> + * @erase_counters: array of erase counter values
> + * @padding: reserved for future, not used, has to be zeroed
> + *
> + * Erase counters are read in range @start_ec_req to @end_ec_req. Range is half-open
> + * i.e erase counter of end_ec_req is not actually included.
> + * The read erase counters are placed in @erase_counters. If a block is bad or if the
> + * erase counter is unknown the value of the block will be set to -1.
> + */
> +struct ubi_ecinfo_req {
> +	__s32 start_ec_req;
> +	__s32 end_ec_req;
> +	__s32 end_ec_res;
> +	__s32 erase_counters[1000];
> +	__s8  padding[84];
> +}  __packed;
> +

Hi Rickard, please move the definition of 'ubi_ecinfo_req' between 
'ubi_rnvol_req' and 'ubi_leb_change_req'. The last part in 
'include/uapi/mtd/ubi-user.h' defines all structures for the ubi volume 
ioctl.
>   #endif /* __UBI_USER_H__ */
> 


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