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authorJens Axboe <axboe@kernel.dk>2021-03-04 12:21:05 -0700
committerJens Axboe <axboe@kernel.dk>2021-03-04 15:45:03 -0700
commitcc440e8738e5c875297ac0e90316745093be7e28 (patch)
treeafa5104417c11531b4d4ec48ef7b0c3a6b0a45dd /kernel
parentdd59a3d595cc10230ded4c8b727b096e16bceeb5 (diff)
kernel: provide create_io_thread() helper
Provide a generic helper for setting up an io_uring worker. Returns a task_struct so that the caller can do whatever setup is needed, then call wake_up_new_task() to kick it into gear. Add a kernel_clone_args member, io_thread, which tells copy_process() to mark the task with PF_IO_WORKER. Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/fork.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index d66cd1014211..d3171e8e88e5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1940,6 +1940,8 @@ static __latent_entropy struct task_struct *copy_process(
p = dup_task_struct(current, node);
if (!p)
goto fork_out;
+ if (args->io_thread)
+ p->flags |= PF_IO_WORKER;
/*
* This _must_ happen before we call free_task(), i.e. before we jump
@@ -2411,6 +2413,34 @@ struct mm_struct *copy_init_mm(void)
}
/*
+ * This is like kernel_clone(), but shaved down and tailored to just
+ * creating io_uring workers. It returns a created task, or an error pointer.
+ * The returned task is inactive, and the caller must fire it up through
+ * wake_up_new_task(p). All signals are blocked in the created task.
+ */
+struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
+{
+ unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|
+ CLONE_IO;
+ struct kernel_clone_args args = {
+ .flags = ((lower_32_bits(flags) | CLONE_VM |
+ CLONE_UNTRACED) & ~CSIGNAL),
+ .exit_signal = (lower_32_bits(flags) & CSIGNAL),
+ .stack = (unsigned long)fn,
+ .stack_size = (unsigned long)arg,
+ .io_thread = 1,
+ };
+ struct task_struct *tsk;
+
+ tsk = copy_process(NULL, 0, node, &args);
+ if (!IS_ERR(tsk)) {
+ sigfillset(&tsk->blocked);
+ sigdelsetmask(&tsk->blocked, sigmask(SIGKILL));
+ }
+ return tsk;
+}
+
+/*
* Ok, this is the main fork-routine.
*
* It copies the process, and if successful kick-starts