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devices: usb: allow arbitrary control request size

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Previously, the maximum control request length that could be passed
through the USB host_backend layer was limited to 1024 bytes.

To lift this limit, remove the fixed-length ControlTransferBuffer
structure definition and replace it with manual buffer allocation.  This
mirrors the behavior of the later part of this function, which already
indexes into the control_buffer to copy the data back from a device to
host transfer.

BUG=chromium:1073503
TEST=Verify adb logcat still works

Change-Id: I7354f6fa237b4df6db7898f27be76ab10faed9f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2161440
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Daniel Verkamp <dverkamp@chromium.org>
Commit-Queue: Daniel Verkamp <dverkamp@chromium.org>
This commit is contained in:
Daniel Verkamp 2020-04-22 10:35:34 -07:00 committed by Commit Bot
parent ed1498678a
commit 9f22e23996
1 changed files with 9 additions and 20 deletions
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29
devices/src/usb/host_backend/host_device.rs
View file

@ -140,30 +140,21 @@ impl HostDevice {
return Ok(());
}
// Default buffer size for control data transfer.
const CONTROL_DATA_BUFFER_SIZE: usize = 1024;
// Allocate a buffer for the control transfer.
// This buffer will hold a UsbRequestSetup struct followed by the data.
let control_buffer_len =
mem::size_of::<UsbRequestSetup>() + self.control_request_setup.length as usize;
let mut control_buffer = vec![0u8; control_buffer_len];
// Buffer type for control transfer. The first 8 bytes is a UsbRequestSetup struct.
#[derive(Copy, Clone)]
#[repr(C, packed)]
struct ControlTransferBuffer {
pub setup: UsbRequestSetup,
pub data: [u8; CONTROL_DATA_BUFFER_SIZE],
}
// Safe because it only has data and has no implicit padding.
unsafe impl DataInit for ControlTransferBuffer {}
let mut control_request = ControlTransferBuffer {
setup: self.control_request_setup,
data: [0; CONTROL_DATA_BUFFER_SIZE],
};
// Copy the control request header.
control_buffer[..mem::size_of::<UsbRequestSetup>()]
.copy_from_slice(self.control_request_setup.as_slice());
let direction = self.control_request_setup.get_direction();
let buffer = if direction == ControlRequestDataPhaseTransferDirection::HostToDevice {
if let Some(buffer) = buffer {
buffer
.read(&mut control_request.data)
.read(&mut control_buffer[mem::size_of::<UsbRequestSetup>()..])
.map_err(Error::ReadBuffer)?;
}
// buffer is consumed here for HostToDevice transfers.
@ -173,8 +164,6 @@ impl HostDevice {
buffer
};
let control_buffer = control_request.as_slice().to_vec();
let mut control_transfer =
Transfer::new_control(control_buffer).map_err(Error::CreateTransfer)?;