io_uring/kbuf: recycle freed mapped buffer ring entries

[linux-2.6-block.git] / io_uring / rw.c

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 8321e004ab13631ae70dd5e880beb6264f93c354..64390d4e20c1875f92d944ad4fddd6c3ad8a140e 100644 (file)
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -912,6 +912,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags)
 
 int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
 {
+       struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
        unsigned int cflags = 0;
        int ret;
 
@@ -928,7 +929,12 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
         * handling arm it.
         */
        if (ret == -EAGAIN) {
-               io_kbuf_recycle(req, issue_flags);
+               /*
+                * Reset rw->len to 0 again to avoid clamping future mshot
+                * reads, in case the buffer size varies.
+                */
+               if (io_kbuf_recycle(req, issue_flags))
+                       rw->len = 0;
                return -EAGAIN;
        }
 
@@ -941,6 +947,7 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
                 * jump to the termination path. This request is then done.
                 */
                cflags = io_put_kbuf(req, issue_flags);
+               rw->len = 0; /* similarly to above, reset len to 0 */
 
                if (io_fill_cqe_req_aux(req,
                                        issue_flags & IO_URING_F_COMPLETE_DEFER,