Convert pci::Bar<SIZE> to pci::Bar<'a, SIZE>, storing &'a Device<Bound> to tie the BAR mapping lifetime to the device.
iomap_region_sized() now returns Result<Bar<'a, SIZE>> directly instead of impl PinInit<Devres<Bar<SIZE>>, Error>. Add Bar::into_devres() to consume the bar and register it as a device-managed resource, returning Devres<Bar<'static, SIZE>>. The lifetime is erased to 'static because Devres guarantees the bar does not actually outlive the device -- access is revoked on unbind. Reviewed-by: Eliot Courtney <[email protected]> Signed-off-by: Danilo Krummrich <[email protected]> --- drivers/gpu/nova-core/driver.rs | 7 +++-- rust/kernel/devres.rs | 2 +- rust/kernel/pci/io.rs | 50 ++++++++++++++++++--------------- samples/rust/rust_driver_pci.rs | 5 ++-- 4 files changed, 35 insertions(+), 29 deletions(-) diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs index 6ad1a856694c..7dbec0470c26 100644 --- a/drivers/gpu/nova-core/driver.rs +++ b/drivers/gpu/nova-core/driver.rs @@ -45,7 +45,7 @@ pub(crate) struct NovaCore { // DMA addresses. These systems should be quite rare. const GPU_DMA_BITS: u32 = 47; -pub(crate) type Bar0 = pci::Bar<BAR0_SIZE>; +pub(crate) type Bar0 = pci::Bar<'static, BAR0_SIZE>; kernel::pci_device_table!( PCI_TABLE, @@ -92,8 +92,9 @@ fn probe<'bound>( // other threads of execution. unsafe { pdev.dma_set_mask_and_coherent(DmaMask::new::<GPU_DMA_BITS>())? }; - let bar = Arc::pin_init( - pdev.iomap_region_sized::<BAR0_SIZE>(0, c"nova-core/bar0"), + let bar = Arc::new( + pdev.iomap_region_sized::<BAR0_SIZE>(0, c"nova-core/bar0")? + .into_devres()?, GFP_KERNEL, )?; diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs index fd4633f977f6..82cbd8b969fb 100644 --- a/rust/kernel/devres.rs +++ b/rust/kernel/devres.rs @@ -304,7 +304,7 @@ pub fn device(&self) -> &Device { /// pci, // /// }; /// - /// fn from_core(dev: &pci::Device<Core<'_>>, devres: Devres<pci::Bar<0x4>>) -> Result { + /// fn from_core(dev: &pci::Device<Core<'_>>, devres: Devres<pci::Bar<'_, 0x4>>) -> Result { /// let bar = devres.access(dev.as_ref())?; /// /// let _ = bar.read32(0x0); diff --git a/rust/kernel/pci/io.rs b/rust/kernel/pci/io.rs index ae78676c927f..6116c55412bc 100644 --- a/rust/kernel/pci/io.rs +++ b/rust/kernel/pci/io.rs @@ -14,8 +14,7 @@ Mmio, MmioRaw, // }, - prelude::*, - sync::aref::ARef, // + prelude::*, // }; use core::{ marker::PhantomData, @@ -146,14 +145,14 @@ impl<'a, S: ConfigSpaceKind> IoKnownSize for ConfigSpace<'a, S> { /// /// `Bar` always holds an `IoRaw` instance that holds a valid pointer to the start of the I/O /// memory mapped PCI BAR and its size. -pub struct Bar<const SIZE: usize = 0> { - pdev: ARef<Device>, +pub struct Bar<'a, const SIZE: usize = 0> { + pdev: &'a Device<device::Bound>, io: MmioRaw<SIZE>, num: i32, } -impl<const SIZE: usize> Bar<SIZE> { - pub(super) fn new(pdev: &Device, num: u32, name: &CStr) -> Result<Self> { +impl<'a, const SIZE: usize> Bar<'a, SIZE> { + pub(super) fn new(pdev: &'a Device<device::Bound>, num: u32, name: &CStr) -> Result<Self> { let len = pdev.resource_len(num)?; if len == 0 { return Err(ENOMEM); @@ -196,11 +195,7 @@ pub(super) fn new(pdev: &Device, num: u32, name: &CStr) -> Result<Self> { } }; - Ok(Bar { - pdev: pdev.into(), - io, - num, - }) + Ok(Bar { pdev, io, num }) } /// # Safety @@ -219,11 +214,24 @@ unsafe fn do_release(pdev: &Device, ioptr: usize, num: i32) { fn release(&self) { // SAFETY: The safety requirements are guaranteed by the type invariant of `self.pdev`. - unsafe { Self::do_release(&self.pdev, self.io.addr(), self.num) }; + unsafe { Self::do_release(self.pdev, self.io.addr(), self.num) }; + } + + /// Consume the `Bar` and register it as a device-managed resource. + /// + /// The returned `Devres<Bar<'static, SIZE>>` can outlive the original lifetime `'a`. Access + /// to the BAR is revoked when the device is unbound. + pub fn into_devres(self) -> Result<Devres<Bar<'static, SIZE>>> { + // SAFETY: Casting to `'static` is sound because `Devres` guarantees the `Bar` does not + // actually outlive the device -- access is revoked and the resource is released when the + // device is unbound. + let bar: Bar<'static, SIZE> = unsafe { core::mem::transmute(self) }; + let pdev = bar.pdev; + Devres::new(pdev.as_ref(), bar) } } -impl Bar { +impl Bar<'_> { #[inline] pub(super) fn index_is_valid(index: u32) -> bool { // A `struct pci_dev` owns an array of resources with at most `PCI_NUM_RESOURCES` entries. @@ -231,13 +239,13 @@ pub(super) fn index_is_valid(index: u32) -> bool { } } -impl<const SIZE: usize> Drop for Bar<SIZE> { +impl<const SIZE: usize> Drop for Bar<'_, SIZE> { fn drop(&mut self) { self.release(); } } -impl<const SIZE: usize> Deref for Bar<SIZE> { +impl<const SIZE: usize> Deref for Bar<'_, SIZE> { type Target = Mmio<SIZE>; fn deref(&self) -> &Self::Target { @@ -252,17 +260,13 @@ impl Device<device::Bound> { pub fn iomap_region_sized<'a, const SIZE: usize>( &'a self, bar: u32, - name: &'a CStr, - ) -> impl PinInit<Devres<Bar<SIZE>>, Error> + 'a { - Devres::new(self.as_ref(), Bar::<SIZE>::new(self, bar, name)) + name: &CStr, + ) -> Result<Bar<'a, SIZE>> { + Bar::new(self, bar, name) } /// Maps an entire PCI BAR after performing a region-request on it. - pub fn iomap_region<'a>( - &'a self, - bar: u32, - name: &'a CStr, - ) -> impl PinInit<Devres<Bar>, Error> + 'a { + pub fn iomap_region<'a>(&'a self, bar: u32, name: &CStr) -> Result<Bar<'a>> { self.iomap_region_sized::<0>(bar, name) } diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs index 6791d98e1c79..0353481b0690 100644 --- a/samples/rust/rust_driver_pci.rs +++ b/samples/rust/rust_driver_pci.rs @@ -45,7 +45,7 @@ mod regs { pub(super) const END: usize = 0x10; } -type Bar0 = pci::Bar<{ regs::END }>; +type Bar0 = pci::Bar<'static, { regs::END }>; #[derive(Copy, Clone, Debug)] struct TestIndex(u8); @@ -161,7 +161,8 @@ fn probe<'bound>( pdev.set_master(); Ok(try_pin_init!(Self { - bar <- pdev.iomap_region_sized::<{ regs::END }>(0, c"rust_driver_pci"), + bar: pdev.iomap_region_sized::<{ regs::END }>(0, c"rust_driver_pci")? + .into_devres()?, index: *info, _: { let bar = bar.access(pdev.as_ref())?; -- 2.54.0
