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Update sqe layout and prep helpers
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Let's be smart about it and actually set aside sqe->futex_flags for
io_uring specific flags, and move the FUTEX2_* flags to sqe->fd instead.
This leaves us open to have tweaks internally for io_uring futex commands,
rather than need to add FUTEX2_ flags for that which may not at all make
any sense for the core futex2(2) syscalls.

This has bitten us in the bit previously and we've had to add a new
opcode rather than just add a flag, the most recent example of that is
the IORING_OP_READ_MULTISHOT which clearly could've just been a flag
for the READ/READV/READ_FIXED opcodes.

While doing so, make sure we have two sets of flags passed to the prep
helpers, so that we're future proof in that regard.

Signed-off-by: Jens Axboe <[email protected]>
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axboe committed Sep 27, 2023
1 parent 54f0f9a commit 0b8fac7
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Showing 2 changed files with 34 additions and 19 deletions.
17 changes: 10 additions & 7 deletions src/include/liburing.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1174,26 +1174,29 @@ IOURINGINLINE void io_uring_prep_waitid(struct io_uring_sqe *sqe,

IOURINGINLINE void io_uring_prep_futex_wake(struct io_uring_sqe *sqe,
uint32_t *futex, uint64_t val,
uint64_t mask, uint32_t flags)
uint64_t mask, uint32_t futex_flags,
unsigned int flags)
{
io_uring_prep_rw(IORING_OP_FUTEX_WAKE, sqe, 0, futex, 0, val);
sqe->futex_flags = flags | 2; /* FLAGS_SIZE_32 */
io_uring_prep_rw(IORING_OP_FUTEX_WAKE, sqe, futex_flags, futex, 0, val);
sqe->futex_flags = flags;
sqe->addr3 = mask;
}

IOURINGINLINE void io_uring_prep_futex_wait(struct io_uring_sqe *sqe,
uint32_t *futex, uint64_t val,
uint64_t mask, uint32_t flags)
uint64_t mask, uint32_t futex_flags,
unsigned int flags)
{
io_uring_prep_rw(IORING_OP_FUTEX_WAIT, sqe, 0, futex, 0, val);
sqe->futex_flags = flags | 2; /* FLAGS_SIZE_32 */
io_uring_prep_rw(IORING_OP_FUTEX_WAIT, sqe, futex_flags, futex, 0, val);
sqe->futex_flags = flags;
sqe->addr3 = mask;
}

struct futex_waitv;
IOURINGINLINE void io_uring_prep_futex_waitv(struct io_uring_sqe *sqe,
struct futex_waitv *futex,
uint32_t nr_futex, uint32_t flags)
uint32_t nr_futex,
unsigned int flags)
{
io_uring_prep_rw(IORING_OP_FUTEX_WAITV, sqe, 0, futex, nr_futex, 0);
sqe->futex_flags = flags;
Expand Down
36 changes: 24 additions & 12 deletions test/futex.c
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Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,8 @@ static void *fwake(void *data)

*futex = 1;
sqe = io_uring_get_sqe(&ring);
io_uring_prep_futex_wake(sqe, futex, 1, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wake(sqe, futex, 1, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);
sqe->user_data = 3;

io_uring_submit(&ring);
Expand Down Expand Up @@ -91,7 +92,8 @@ static int __test(struct io_uring *ring, int vectored, int async,
if (vectored)
io_uring_prep_futex_waitv(sqe, fw, nfutex, 0);
else
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);
if (async)
sqe->flags |= IOSQE_ASYNC;
sqe->user_data = 1;
Expand Down Expand Up @@ -186,14 +188,16 @@ static int test_order(int vectored, int async)
*/
sqe = io_uring_get_sqe(&ring);
if (!vectored)
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);
else
io_uring_prep_futex_waitv(sqe, &fw, 1, 0);
sqe->user_data = 1;

sqe = io_uring_get_sqe(&ring);
if (!vectored)
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);
else
io_uring_prep_futex_waitv(sqe, &fw, 1, 0);
sqe->user_data = 2;
Expand All @@ -205,7 +209,8 @@ static int test_order(int vectored, int async)
*/
*futex = 1;
sqe = io_uring_get_sqe(&ring);
io_uring_prep_futex_wake(sqe, futex, 1, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wake(sqe, futex, 1, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);
sqe->user_data = 100;
if (async)
sqe->flags |= IOSQE_ASYNC;
Expand Down Expand Up @@ -266,14 +271,16 @@ static int test_multi_wake(int vectored)
*/
sqe = io_uring_get_sqe(&ring);
if (!vectored)
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);
else
io_uring_prep_futex_waitv(sqe, &fw, 1, 0);
sqe->user_data = 1;

sqe = io_uring_get_sqe(&ring);
if (!vectored)
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);
else
io_uring_prep_futex_waitv(sqe, &fw, 1, 0);
sqe->user_data = 2;
Expand All @@ -285,7 +292,8 @@ static int test_multi_wake(int vectored)
*/
*futex = 1;
sqe = io_uring_get_sqe(&ring);
io_uring_prep_futex_wake(sqe, futex, 2, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wake(sqe, futex, 2, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);
sqe->user_data = 100;

io_uring_submit(&ring);
Expand Down Expand Up @@ -337,13 +345,15 @@ static int test_wake_zero(void)

sqe = io_uring_get_sqe(&ring);
sqe->user_data = 1;
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);

io_uring_submit(&ring);

sqe = io_uring_get_sqe(&ring);
sqe->user_data = 2;
io_uring_prep_futex_wake(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0);
io_uring_prep_futex_wake(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY,
FUTEX2_SIZE_U32, 0);

io_uring_submit(&ring);

Expand Down Expand Up @@ -392,7 +402,8 @@ static int test_invalid(void)

sqe = io_uring_get_sqe(&ring);
sqe->user_data = 1;
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0x1000);
io_uring_prep_futex_wait(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0x1000,
0);

io_uring_submit(&ring);

Expand All @@ -409,7 +420,8 @@ static int test_invalid(void)

sqe = io_uring_get_sqe(&ring);
sqe->user_data = 1;
io_uring_prep_futex_wake(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0x1000);
io_uring_prep_futex_wake(sqe, futex, 0, FUTEX_BITSET_MATCH_ANY, 0x1000,
0);

io_uring_submit(&ring);

Expand Down

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