Fixed MTP to work with TWRP

Documentation/blockdev/zram.txt

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+zram: Compressed RAM based block devices
+----------------------------------------
+
+* Introduction
+
+The zram module creates RAM based block devices named /dev/zram<id>
+(<id> = 0, 1, ...). Pages written to these disks are compressed and stored
+in memory itself. These disks allow very fast I/O and compression provides
+good amounts of memory savings. Some of the usecases include /tmp storage,
+use as swap disks, various caches under /var and maybe many more :)
+
+Statistics for individual zram devices are exported through sysfs nodes at
+/sys/block/zram<id>/
+
+* Usage
+
+Following shows a typical sequence of steps for using zram.
+
+1) Load Module:
+	modprobe zram num_devices=4
+	This creates 4 devices: /dev/zram{0,1,2,3}
+	(num_devices parameter is optional. Default: 1)
+
+2) Set max number of compression streams
+	Compression backend may use up to max_comp_streams compression streams,
+	thus allowing up to max_comp_streams concurrent compression operations.
+	By default, compression backend uses single compression stream.
+
+	Examples:
+	#show max compression streams number
+	cat /sys/block/zram0/max_comp_streams
+
+	#set max compression streams number to 3
+	echo 3 > /sys/block/zram0/max_comp_streams
+
+Note:
+In order to enable compression backend's multi stream support max_comp_streams
+must be initially set to desired concurrency level before ZRAM device
+initialisation. Once the device initialised as a single stream compression
+backend (max_comp_streams equals to 1), you will see error if you try to change
+the value of max_comp_streams because single stream compression backend
+implemented as a special case by lock overhead issue and does not support
+dynamic max_comp_streams. Only multi stream backend supports dynamic
+max_comp_streams adjustment.
+
+3) Select compression algorithm
+	Using comp_algorithm device attribute one can see available and
+	currently selected (shown in square brackets) compression algortithms,
+	change selected compression algorithm (once the device is initialised
+	there is no way to change compression algorithm).
+
+	Examples:
+	#show supported compression algorithms
+	cat /sys/block/zram0/comp_algorithm
+	lzo [lz4]
+
+	#select lzo compression algorithm
+	echo lzo > /sys/block/zram0/comp_algorithm
+
+4) Set Disksize
+        Set disk size by writing the value to sysfs node 'disksize'.
+        The value can be either in bytes or you can use mem suffixes.
+        Examples:
+            # Initialize /dev/zram0 with 50MB disksize
+            echo $((50*1024*1024)) > /sys/block/zram0/disksize
+
+            # Using mem suffixes
+            echo 256K > /sys/block/zram0/disksize
+            echo 512M > /sys/block/zram0/disksize
+            echo 1G > /sys/block/zram0/disksize
+
+Note:
+There is little point creating a zram of greater than twice the size of memory
+since we expect a 2:1 compression ratio. Note that zram uses about 0.1% of the
+size of the disk when not in use so a huge zram is wasteful.
+
+5) Set memory limit: Optional
+	Set memory limit by writing the value to sysfs node 'mem_limit'.
+	The value can be either in bytes or you can use mem suffixes.
+	In addition, you could change the value in runtime.
+	Examples:
+	    # limit /dev/zram0 with 50MB memory
+	    echo $((50*1024*1024)) > /sys/block/zram0/mem_limit
+
+	    # Using mem suffixes
+	    echo 256K > /sys/block/zram0/mem_limit
+	    echo 512M > /sys/block/zram0/mem_limit
+	    echo 1G > /sys/block/zram0/mem_limit
+
+	    # To disable memory limit
+	    echo 0 > /sys/block/zram0/mem_limit
+
+6) Activate:
+	mkswap /dev/zram0
+	swapon /dev/zram0
+
+	mkfs.ext4 /dev/zram1
+	mount /dev/zram1 /tmp
+
+7) Stats:
+	Per-device statistics are exported as various nodes under
+	/sys/block/zram<id>/
+		disksize
+		num_reads
+		num_writes
+		failed_reads
+		failed_writes
+		invalid_io
+		notify_free
+		zero_pages
+		orig_data_size
+		compr_data_size
+		mem_used_total
+		mem_used_max
+
+8) Deactivate:
+	swapoff /dev/zram0
+	umount /dev/zram1
+
+9) Reset:
+	Write any positive value to 'reset' sysfs node
+	echo 1 > /sys/block/zram0/reset
+	echo 1 > /sys/block/zram1/reset
+
+	This frees all the memory allocated for the given device and
+	resets the disksize to zero. You must set the disksize again
+	before reusing the device.
+
+Nitin Gupta
+ngupta@vflare.org