Prepare for supporting to notify uring_cmd driver when ctx/io_uring_task
is going away.
Notifier callback will be registered by driver to get notified, so that driver
can cancel in-flight command which may depend on the io task.
For driver to check if the ctx is matched with uring_cmd, allocate/provide ctx
id to the callback, so we can avoid to expose the whole ctx instance.
The global xarray of ctx_ids is added for holding the mapping and allocating
unique id for each ctx.
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
include/linux/io_uring.h | 2 ++
include/linux/io_uring_types.h | 3 +++
io_uring/io_uring.c | 9 +++++++++
3 files changed, 14 insertions(+)
diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 106cdc55ff3b..ec9714e36477 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -41,6 +41,8 @@ static inline const void *io_uring_sqe_cmd(const struct io_uring_sqe *sqe)
return sqe->cmd;
}
+#define IO_URING_INVALID_CTX_ID UINT_MAX
+
#if defined(CONFIG_IO_URING)
int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
struct iov_iter *iter, void *ioucmd);
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 13d19b9be9f4..d310bb073101 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -215,6 +215,9 @@ struct io_ring_ctx {
struct percpu_ref refs;
enum task_work_notify_mode notify_method;
+
+ /* for uring cmd driver to retrieve context */
+ unsigned int id;
} ____cacheline_aligned_in_smp;
/* submission data */
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 783ed0fff71b..c015c070ff85 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -175,6 +175,9 @@ static struct ctl_table kernel_io_uring_disabled_table[] = {
};
#endif
+/* mapping between io_ring_ctx instance and its ctx_id */
+static DEFINE_XARRAY_FLAGS(ctx_ids, XA_FLAGS_ALLOC);
+
struct sock *io_uring_get_socket(struct file *file)
{
#if defined(CONFIG_UNIX)
@@ -303,6 +306,10 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
xa_init(&ctx->io_bl_xa);
+ ctx->id = IO_URING_INVALID_CTX_ID;
+ if (xa_alloc(&ctx_ids, &ctx->id, ctx, xa_limit_31b, GFP_KERNEL))
+ goto err;
+
/*
* Use 5 bits less than the max cq entries, that should give us around
* 32 entries per hash list if totally full and uniformly spread, but
@@ -356,6 +363,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
kfree(ctx->cancel_table_locked.hbs);
kfree(ctx->io_bl);
xa_destroy(&ctx->io_bl_xa);
+ xa_erase(&ctx_ids, ctx->id);
kfree(ctx);
return NULL;
}
@@ -2929,6 +2937,7 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
kfree(ctx->cancel_table_locked.hbs);
kfree(ctx->io_bl);
xa_destroy(&ctx->io_bl_xa);
+ xa_erase(&ctx_ids, ctx->id);
kfree(ctx);
}
--
2.40.1
