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io_uring: return back safer resurrect
Revert of revert of "io_uring: wait potential ->release() on resurrect",
which adds a helper for resurrect not racing completion reinit, as was
removed because of a strange bug with no clear root or link to the
patch.
Was improved, instead of rcu_synchronize(), just wait_for_completion()
because we're at 0 refs and it will happen very shortly. Specifically
use non-interruptible version to ignore all pending signals that may
have ended prior interruptible wait.
This reverts commit cb5e1b8130
.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7a080c20f686d026efade810b116b72f88abaff9.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
parent
e4335ed33e
commit
f70865db5f
1 changed files with 14 additions and 4 deletions
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@ -1081,6 +1081,18 @@ static inline void io_req_set_rsrc_node(struct io_kiocb *req)
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}
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}
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static void io_refs_resurrect(struct percpu_ref *ref, struct completion *compl)
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{
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bool got = percpu_ref_tryget(ref);
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/* already at zero, wait for ->release() */
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if (!got)
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wait_for_completion(compl);
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percpu_ref_resurrect(ref);
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if (got)
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percpu_ref_put(ref);
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}
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static bool io_match_task(struct io_kiocb *head,
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struct task_struct *task,
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struct files_struct *files)
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@ -9788,12 +9800,11 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
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if (ret < 0)
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break;
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} while (1);
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mutex_lock(&ctx->uring_lock);
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if (ret) {
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percpu_ref_resurrect(&ctx->refs);
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goto out_quiesce;
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io_refs_resurrect(&ctx->refs, &ctx->ref_comp);
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return ret;
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}
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}
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@ -9886,7 +9897,6 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
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if (io_register_op_must_quiesce(opcode)) {
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/* bring the ctx back to life */
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percpu_ref_reinit(&ctx->refs);
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out_quiesce:
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reinit_completion(&ctx->ref_comp);
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}
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return ret;
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