Merge "Use FUNCTIONFS_ENDPOINT_ALLOC_BUFFER ioctl to improve performance."

#define cpu_to_le16(x)  htole16(x)

#define cpu_to_le32(x)  htole32(x)

#define FUNCTIONFS_ENDPOINT_ALLOC       _IOR('g', 131, __u32)

namespace {

constexpr char FFS_MTP_EP_IN[] = "/dev/usb-ffs/mtp/ep1";

    mLock.unlock();

}

class ScopedEndpointBufferAlloc {

private:

    const int mFd;

    const unsigned int mAllocSize;

public:

    ScopedEndpointBufferAlloc(int fd, unsigned alloc_size) :

        mFd(fd),

        mAllocSize(alloc_size) {

        if (ioctl(mFd, FUNCTIONFS_ENDPOINT_ALLOC, static_cast<__u32>(mAllocSize)))

            PLOG(DEBUG) << "FFS endpoint alloc failed!";

    }

    ~ScopedEndpointBufferAlloc() {

        if (ioctl(mFd, FUNCTIONFS_ENDPOINT_ALLOC, static_cast<__u32>(0)))

            PLOG(DEBUG) << "FFS endpoint alloc reset failed!";

    }

};

/* Read from USB and write to a local file. */

int MtpFfsHandle::receiveFile(mtp_file_range mfr) {

    // When receiving files, the incoming length is given in 32 bits.

    bool write = false;

    posix_fadvise(mfr.fd, 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE);

    ScopedEndpointBufferAlloc(mBulkOut, mMaxRead);

    // Break down the file into pieces that fit in buffers

    while (file_length > 0 || write) {

    if (writeHandle(mBulkIn, data, packet_size) == -1) return -1;

    if (file_length == 0) return 0;

    ScopedEndpointBufferAlloc(mBulkIn, mMaxWrite);

    // Break down the file into pieces that fit in buffers

    while(file_length > 0) {

        if (read) {