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-rw-r--r--io_uring/kbuf.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 7b9a0f5d08c6..07dbb0d17aae 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -83,6 +83,39 @@ static int io_buffer_add_list(struct io_ring_ctx *ctx,
return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL));
}
+unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags)
+{
+ unsigned int cflags;
+
+ /*
+ * We can add this buffer back to two lists:
+ *
+ * 1) The io_buffers_cache list. This one is protected by the
+ * ctx->uring_lock. If we already hold this lock, add back to this
+ * list as we can grab it from issue as well.
+ * 2) The io_buffers_comp list. This one is protected by the
+ * ctx->completion_lock.
+ *
+ * We migrate buffers from the comp_list to the issue cache list
+ * when we need one.
+ */
+ if (req->flags & REQ_F_BUFFER_RING) {
+ /* no buffers to recycle for this case */
+ cflags = __io_put_kbuf_list(req, NULL);
+ } else if (issue_flags & IO_URING_F_UNLOCKED) {
+ struct io_ring_ctx *ctx = req->ctx;
+
+ spin_lock(&ctx->completion_lock);
+ cflags = __io_put_kbuf_list(req, &ctx->io_buffers_comp);
+ spin_unlock(&ctx->completion_lock);
+ } else {
+ lockdep_assert_held(&req->ctx->uring_lock);
+
+ cflags = __io_put_kbuf_list(req, &req->ctx->io_buffers_cache);
+ }
+ return cflags;
+}
+
static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len,
struct io_buffer_list *bl)
{