The pointer passed to the kernel for the iovecs must remain valid until
the operation completes. This is true even if the kernel copies the sqe
containing the pointer, that isn't a deep copy. If the iovecs are freed
before the kernel actually processes the op, it will fail with a bad
address error.
Move the responsibility for maintaining the list in memory from the
caller to io_uring itself. This mean io_uring must allocate. Taking
iterators for IoSlice/IoSliceMut, means that the caller doesn't need to
allocate as well if there isn't a Vec already allocated.
Change-Id: I63a009d8ab543c8bac4132809fb851536d4ad82c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2227082
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
The kernel is allowed to not only limit the number of requested entries,
but also provide more than is requested. If a non-power-of-2 is
requested, it will be rounded up to the next power of 2.
Ensure that there are enough iovecs by allocating them based on the
number returned from io_uring_setup instead of the number of entries
requested.
TEST=cargo test read_parallel
Change-Id: If92e0a31858d1af53b99af8415002a4f26b48230
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2140915
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Dylan Reid <dgreid@chromium.org>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
Let the user of the io_uring interface specify a slice of iovecs to read
from or write to when queueing an operation to the ring.
These ops can be used by block that has a Vec of iovecs from the
descriptor chain already.
Change-Id: Ia91e03e441cdae03e4fdba33bb601de006ef53ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2140914
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Dylan Reid <dgreid@chromium.org>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
Switch from returning an i32 to a u32. This will make handling the
number easier for users, as they can assume it is >= 0.
Any value < 0 would not be returned as Ok(value) anyways as ret < 0 is
used for error conditions.
Change-Id: I609ce55d3c6be6e28f4d7aadf7148b2ac3b18878
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2140913
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Dylan Reid <dgreid@chromium.org>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
Provide a low-level interface to operating the new io_uring interface.
This is an unsafe interface with the basic operations of setting up the
ring, adding to it, removing from it, and polling it.
This will be followed by a safe interface layer on top of this code,
then by additions to the asynchronous executor that allow for
asynchronously doing multiple operations to files from one context.
Change-Id: I71f7ffb04ce8cb4da470deda9aee768ab95d3d98
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2124009
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
