diff options
Diffstat (limited to 'rust/kernel/dma.rs')
| -rw-r--r-- | rust/kernel/dma.rs | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs index 4e0af3e1a3b9..84d3c67269e8 100644 --- a/rust/kernel/dma.rs +++ b/rust/kernel/dma.rs @@ -12,6 +12,7 @@ use crate::{ sync::aref::ARef, transmute::{AsBytes, FromBytes}, }; +use core::ptr::NonNull; /// DMA address type. /// @@ -358,7 +359,7 @@ pub struct CoherentAllocation<T: AsBytes + FromBytes> { dev: ARef<device::Device>, dma_handle: DmaAddress, count: usize, - cpu_addr: *mut T, + cpu_addr: NonNull<T>, dma_attrs: Attrs, } @@ -392,7 +393,7 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> { .ok_or(EOVERFLOW)?; let mut dma_handle = 0; // SAFETY: Device pointer is guaranteed as valid by the type invariant on `Device`. - let ret = unsafe { + let addr = unsafe { bindings::dma_alloc_attrs( dev.as_raw(), size, @@ -401,9 +402,7 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> { dma_attrs.as_raw(), ) }; - if ret.is_null() { - return Err(ENOMEM); - } + let addr = NonNull::new(addr).ok_or(ENOMEM)?; // INVARIANT: // - We just successfully allocated a coherent region which is accessible for // `count` elements, hence the cpu address is valid. We also hold a refcounted reference @@ -414,7 +413,7 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> { dev: dev.into(), dma_handle, count, - cpu_addr: ret.cast::<T>(), + cpu_addr: addr.cast(), dma_attrs, }) } @@ -446,13 +445,13 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> { /// Returns the base address to the allocated region in the CPU's virtual address space. pub fn start_ptr(&self) -> *const T { - self.cpu_addr + self.cpu_addr.as_ptr() } /// Returns the base address to the allocated region in the CPU's virtual address space as /// a mutable pointer. pub fn start_ptr_mut(&mut self) -> *mut T { - self.cpu_addr + self.cpu_addr.as_ptr() } /// Returns a DMA handle which may be given to the device as the DMA address base of @@ -505,7 +504,7 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> { // data is also guaranteed by the safety requirements of the function. // - `offset + count` can't overflow since it is smaller than `self.count` and we've checked // that `self.count` won't overflow early in the constructor. - Ok(unsafe { core::slice::from_raw_parts(self.cpu_addr.add(offset), count) }) + Ok(unsafe { core::slice::from_raw_parts(self.start_ptr().add(offset), count) }) } /// Performs the same functionality as [`CoherentAllocation::as_slice`], except that a mutable @@ -525,7 +524,7 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> { // data is also guaranteed by the safety requirements of the function. // - `offset + count` can't overflow since it is smaller than `self.count` and we've checked // that `self.count` won't overflow early in the constructor. - Ok(unsafe { core::slice::from_raw_parts_mut(self.cpu_addr.add(offset), count) }) + Ok(unsafe { core::slice::from_raw_parts_mut(self.start_ptr_mut().add(offset), count) }) } /// Writes data to the region starting from `offset`. `offset` is in units of `T`, not the @@ -557,7 +556,11 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> { // - `offset + count` can't overflow since it is smaller than `self.count` and we've checked // that `self.count` won't overflow early in the constructor. unsafe { - core::ptr::copy_nonoverlapping(src.as_ptr(), self.cpu_addr.add(offset), src.len()) + core::ptr::copy_nonoverlapping( + src.as_ptr(), + self.start_ptr_mut().add(offset), + src.len(), + ) }; Ok(()) } @@ -576,7 +579,7 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> { // and we've just checked that the range and index is within bounds. // - `offset` can't overflow since it is smaller than `self.count` and we've checked // that `self.count` won't overflow early in the constructor. - Ok(unsafe { self.cpu_addr.add(offset) }) + Ok(unsafe { self.cpu_addr.as_ptr().add(offset) }) } /// Reads the value of `field` and ensures that its type is [`FromBytes`]. @@ -637,7 +640,7 @@ impl<T: AsBytes + FromBytes> Drop for CoherentAllocation<T> { bindings::dma_free_attrs( self.dev.as_raw(), size, - self.cpu_addr.cast(), + self.start_ptr_mut().cast(), self.dma_handle, self.dma_attrs.as_raw(), ) |