UBI: allow direct user-space I/O (766fb95b) · Commits · e / devices / android_kernel_oneplus_sm7250

drivers/mtd/ubi/Kconfig.debug

+0 −10

Original line number	Diff line number	Diff line
		@@ -33,16 +33,6 @@ config MTD_UBI_DEBUG_DISABLE_BGT
		This option switches the background thread off by default. The thread
		may be also be enabled/disabled via UBI sysfs.

		config MTD_UBI_DEBUG_USERSPACE_IO
		bool "Direct user-space write/erase support"
		default n
		depends on MTD_UBI_DEBUG
		help
		By default, users cannot directly write and erase individual
		eraseblocks of dynamic volumes, and have to use update operation
		instead. This option enables this capability - it is very useful for
		debugging and testing.

		config MTD_UBI_DEBUG_EMULATE_BITFLIPS
		bool "Emulate flash bit-flips"
		depends on MTD_UBI_DEBUG

drivers/mtd/ubi/cdev.c

+28 −8

Original line number	Diff line number	Diff line
		@@ -259,12 +259,9 @@ static ssize_t vol_cdev_read(struct file file, __user char buf, size_t count,
		return err ? err : count_save - count;
		}

		#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO

		/*
		* This function allows to directly write to dynamic UBI volumes, without
		* issuing the volume update operation. Available only as a debugging feature.
		* Very useful for testing UBI.
		* issuing the volume update operation.
		*/
		static ssize_t vol_cdev_direct_write(struct file file, const char __user buf,
		size_t count, loff_t *offp)
		@@ -276,6 +273,9 @@ static ssize_t vol_cdev_direct_write(struct file file, const char __user buf,
		size_t count_save = count;
		char *tbuf;

		if (!vol->direct_writes)
		return -EPERM;

		dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
		count, *offp, vol->vol_id);

		@@ -339,10 +339,6 @@ static ssize_t vol_cdev_direct_write(struct file file, const char __user buf,
		return err ? err : count_save - count;
		}

		#else
		#define vol_cdev_direct_write(file, buf, count, offp) (-EPERM)
		#endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */

		static ssize_t vol_cdev_write(struct file file, const char __user buf,
		size_t count, loff_t *offp)
		{
		@@ -552,6 +548,30 @@ static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
		break;
		}

		/* Set volume property command*/
		case UBI_IOCSETPROP:
		{
		struct ubi_set_prop_req req;

		err = copy_from_user(&req, argp,
		sizeof(struct ubi_set_prop_req));
		if (err) {
		err = -EFAULT;
		break;
		}
		switch (req.property) {
		case UBI_PROP_DIRECT_WRITE:
		mutex_lock(&ubi->volumes_mutex);
		desc->vol->direct_writes = !!req.value;
		mutex_unlock(&ubi->volumes_mutex);
		break;
		default:
		err = -EINVAL;
		break;
		}
		break;
		}

		default:
		err = -ENOTTY;
		break;

drivers/mtd/ubi/ubi.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -206,6 +206,7 @@ struct ubi_volume_desc;
		* @upd_marker: %1 if the update marker is set for this volume
		* @updating: %1 if the volume is being updated
		* @changing_leb: %1 if the atomic LEB change ioctl command is in progress
		* @direct_writes: %1 if direct writes are enabled for this volume
		*
		* @gluebi_desc: gluebi UBI volume descriptor
		* @gluebi_refcount: reference count of the gluebi MTD device
		@@ -253,6 +254,7 @@ struct ubi_volume {
		unsigned int upd_marker:1;
		unsigned int updating:1;
		unsigned int changing_leb:1;
		unsigned int direct_writes:1;

		#ifdef CONFIG_MTD_UBI_GLUEBI
		/*
		@@ -304,7 +306,8 @@ struct ubi_wl_entry;
		* @vtbl_size: size of the volume table in bytes
		* @vtbl: in-RAM volume table copy
		* @volumes_mutex: protects on-flash volume table and serializes volume
		* changes, like creation, deletion, update, re-size and re-name
		* changes, like creation, deletion, update, re-size,
		* re-name and set property
		*
		* @max_ec: current highest erase counter value
		* @mean_ec: current mean erase counter value

include/mtd/ubi-user.h

+34 −0

Original line number	Diff line number	Diff line
		@@ -124,6 +124,14 @@
		* To check if a logical eraseblock is mapped to a physical eraseblock, the
		* %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
		* not mapped, and %1 if it is mapped.
		*
		* Set an UBI volume property
		* ~~~~~~~~~~~~~~~~~~~~~~~~~
		*
		* To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
		* used. A pointer to a &struct ubi_set_prop_req object is expected to be
		* passed. The object describes which property should be set, and to which value
		* it should be set.
		*/

		/*
		@@ -175,6 +183,8 @@
		#define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, int32_t)
		/* Check if LEB is mapped command */
		#define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, int32_t)
		/* Set an UBI volume property */
		#define UBI_IOCSETPROP _IOW(UBI_VOL_IOC_MAGIC, 6, struct ubi_set_prop_req)

		/* Maximum MTD device name length supported by UBI */
		#define MAX_UBI_MTD_NAME_LEN 127
		@@ -210,6 +220,16 @@ enum {
		UBI_STATIC_VOLUME = 4,
		};

		/*
		* UBI set property ioctl constants
		*
		* @UBI_PROP_DIRECT_WRITE: allow / disallow user to directly write and
		* erase individual eraseblocks on dynamic volumes
		*/
		enum {
		UBI_PROP_DIRECT_WRITE = 1,
		};

		/**
		* struct ubi_attach_req - attach MTD device request.
		* @ubi_num: UBI device number to create
		@@ -373,4 +393,18 @@ struct ubi_map_req {
		int8_t padding[3];
		} __attribute__ ((packed));


		/**
		* struct ubi_set_prop_req - a data structure used to set an ubi volume
		* property.
		* @property: property to set (%UBI_PROP_DIRECT_WRITE)
		* @padding: reserved for future, not used, has to be zeroed
		* @value: value to set
		*/
		struct ubi_set_prop_req {
		uint8_t property;
		uint8_t padding[7];
		uint64_t value;
		} __attribute__ ((packed));

		#endif /* __UBI_USER_H__ */