USB: gadget: f_mtp: Support for file transfer length greater than 4 gigabytes
For backward compatibility with PTP, MTP is limited to a 32-bit file size.
When transferring files greater than 4 gig, MTP uses 0xFFFFFFFF as the file size
and the receiver reads until it receives a short packet.
Expanded size of mtp_file_range.length to 64 bits and added support for
writing zero length packets.
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/drivers/usb/gadget/f_mtp.c b/drivers/usb/gadget/f_mtp.c
index 81cc018..03ea4a7 100644
--- a/drivers/usb/gadget/f_mtp.c
+++ b/drivers/usb/gadget/f_mtp.c
@@ -107,7 +107,7 @@
struct work_struct receive_file_work;
struct file *xfer_file;
loff_t xfer_file_offset;
- size_t xfer_file_length;
+ int64_t xfer_file_length;
int xfer_result;
};
@@ -558,7 +558,8 @@
dev->state = STATE_BUSY;
spin_unlock_irq(&dev->lock);
- while (count > 0) {
+ /* condition check at bottom to allow zero length packet write */
+ do {
if (dev->state != STATE_BUSY) {
DBG(cdev, "mtp_write dev->error\n");
r = -EIO;
@@ -579,7 +580,7 @@
xfer = BULK_BUFFER_SIZE;
else
xfer = count;
- if (copy_from_user(req->buf, buf, xfer)) {
+ if (xfer && copy_from_user(req->buf, buf, xfer)) {
r = -EFAULT;
break;
}
@@ -597,7 +598,7 @@
/* zero this so we don't try to free it on error exit */
req = 0;
- }
+ } while (count > 0);
if (req)
req_put(dev, &dev->tx_idle, req);
@@ -620,9 +621,10 @@
struct usb_request *req = 0;
struct file *filp;
loff_t offset;
- size_t count;
+ int64_t count;
int xfer, ret;
int r = 0;
+ int sendZLP = 0;
/* read our parameters */
smp_rmb();
@@ -630,9 +632,22 @@
offset = dev->xfer_file_offset;
count = dev->xfer_file_length;
- DBG(cdev, "send_file_work(%lld %u)\n", offset, count);
+ DBG(cdev, "send_file_work(%lld %lld)\n", offset, count);
- while (count > 0) {
+ /* we need to send a zero length packet to signal the end of transfer
+ * if the length is > 4 gig and the last packet is aligned to a
+ * packet boundary.
+ */
+ if (dev->xfer_file_length >= 0xFFFFFFFF
+ && (dev->xfer_file_length & (dev->ep_in->maxpacket - 1)) == 0) {
+ sendZLP = 1;
+ }
+
+ while (count > 0 || sendZLP) {
+ /* so we exit after sending ZLP */
+ if (count == 0)
+ sendZLP = 0;
+
/* get an idle tx request to use */
req = 0;
ret = wait_event_interruptible(dev->write_wq,
@@ -686,7 +701,7 @@
struct usb_request *read_req = NULL, *write_req = NULL;
struct file *filp;
loff_t offset;
- size_t count;
+ int64_t count;
int ret, cur_buf = 0;
int r = 0;
@@ -696,7 +711,7 @@
offset = dev->xfer_file_offset;
count = dev->xfer_file_length;
- DBG(cdev, "receive_file_work(%u)\n", count);
+ DBG(cdev, "receive_file_work(%lld)\n", count);
while (count > 0 || write_req) {
if (count > 0) {
@@ -713,7 +728,6 @@
dev->state = STATE_ERROR;
break;
}
- count -= ret;
}
if (write_req) {
@@ -737,7 +751,17 @@
r = ret;
break;
}
- count -= read_req->actual;
+ /* if xfer_file_length is 0xFFFFFFFF, then we read until
+ * we get a zero length packet
+ */
+ if (count != 0xFFFFFFFF)
+ count -= read_req->actual;
+ if (read_req->actual < read_req->length) {
+ /* short packet is used to signal EOF for sizes > 4 gig */
+ DBG(cdev, "got short packet\n");
+ count = 0;
+ }
+
write_req = read_req;
read_req = NULL;
}