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-rw-r--r--io_uring/kbuf.c15
-rw-r--r--io_uring/kbuf.h2
2 files changed, 13 insertions, 4 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 011280d873e7a..2edc6854f6f3e 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -61,6 +61,7 @@ static int io_buffer_add_list(struct io_ring_ctx *ctx,
* always under the ->uring_lock, but the RCU lookup from mmap does.
*/
bl->bgid = bgid;
+ atomic_set(&bl->refs, 1);
return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL));
}
@@ -265,6 +266,14 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx,
return i;
}
+static void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl)
+{
+ if (atomic_dec_and_test(&bl->refs)) {
+ __io_remove_buffers(ctx, bl, -1U);
+ kfree_rcu(bl, rcu);
+ }
+}
+
void io_destroy_buffers(struct io_ring_ctx *ctx)
{
struct io_buffer_list *bl;
@@ -274,8 +283,7 @@ void io_destroy_buffers(struct io_ring_ctx *ctx)
xa_for_each(&ctx->io_bl_xa, index, bl) {
xa_erase(&ctx->io_bl_xa, bl->bgid);
- __io_remove_buffers(ctx, bl, -1U);
- kfree_rcu(bl, rcu);
+ io_put_bl(ctx, bl);
}
/*
@@ -680,9 +688,8 @@ int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
if (!bl->is_buf_ring)
return -EINVAL;
- __io_remove_buffers(ctx, bl, -1U);
xa_erase(&ctx->io_bl_xa, bl->bgid);
- kfree_rcu(bl, rcu);
+ io_put_bl(ctx, bl);
return 0;
}
diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h
index fdbb104495132..8b868a1744e2f 100644
--- a/io_uring/kbuf.h
+++ b/io_uring/kbuf.h
@@ -25,6 +25,8 @@ struct io_buffer_list {
__u16 head;
__u16 mask;
+ atomic_t refs;
+
/* ring mapped provided buffers */
__u8 is_buf_ring;
/* ring mapped provided buffers, but mmap'ed by application */