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| author | Pavel Begunkov <asml.silence@gmail.com> | 2024-11-15 16:54:43 +0000 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-11-15 12:28:38 -0700 |
| commit | d617b3147d54c42351eac63b5398d4ddf4f4011b (patch) | |
| tree | 9ef5fadb2c80f441e9a65ad9d81ef8dacef1c8d7 /io_uring/register.c | |
| parent | 93238e66185524aad925acefb2312203b9e26d63 (diff) | |
| download | linux-d617b3147d54c42351eac63b5398d4ddf4f4011b.tar.gz linux-d617b3147d54c42351eac63b5398d4ddf4f4011b.tar.bz2 linux-d617b3147d54c42351eac63b5398d4ddf4f4011b.zip | |
io_uring: restore back registered wait arguments
Now we've got a more generic region registration API, place
IORING_ENTER_EXT_ARG_REG and re-enable it.
First, the user has to register a region with the
IORING_MEM_REGION_REG_WAIT_ARG flag set. It can only be done for a
ring in a disabled state, aka IORING_SETUP_R_DISABLED, to avoid races
with already running waiters. With that we should have stable constant
values for ctx->cq_wait_{size,arg} in io_get_ext_arg_reg() and hence no
READ_ONCE required.
The other API difference is that we're now passing byte offsets instead
of indexes. The user _must_ align all offsets / pointers to the native
word size, failing to do so might but not necessarily has to lead to a
failure usually returned as -EFAULT. liburing will be hiding this
details from users.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/81822c1b4ffbe8ad391b4f9ad1564def0d26d990.1731689588.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/register.c')
| -rw-r--r-- | io_uring/register.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/io_uring/register.c b/io_uring/register.c index 2cbac3d9b288..1a60f4916649 100644 --- a/io_uring/register.c +++ b/io_uring/register.c @@ -588,7 +588,16 @@ static int io_register_mem_region(struct io_ring_ctx *ctx, void __user *uarg) if (memchr_inv(®.__resv, 0, sizeof(reg.__resv))) return -EINVAL; - if (reg.flags) + if (reg.flags & ~IORING_MEM_REGION_REG_WAIT_ARG) + return -EINVAL; + + /* + * This ensures there are no waiters. Waiters are unlocked and it's + * hard to synchronise with them, especially if we need to initialise + * the region. + */ + if ((reg.flags & IORING_MEM_REGION_REG_WAIT_ARG) && + !(ctx->flags & IORING_SETUP_R_DISABLED)) return -EINVAL; ret = io_create_region(ctx, &ctx->param_region, &rd); @@ -598,6 +607,11 @@ static int io_register_mem_region(struct io_ring_ctx *ctx, void __user *uarg) io_free_region(ctx, &ctx->param_region); return -EFAULT; } + + if (reg.flags & IORING_MEM_REGION_REG_WAIT_ARG) { + ctx->cq_wait_arg = io_region_get_ptr(&ctx->param_region); + ctx->cq_wait_size = rd.size; + } return 0; } |