io_uring/kbuf: simplify __io_put_kbuf

As a preparation step remove an optimisation from __io_put_kbuf() trying
to use the locked cache. With that __io_put_kbuf_list() is only used
with ->io_buffers_comp, and we remove the explicit list argument.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1b7f1394ec4afc7f96b35a61f5992e27c49fd067.1738724373.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 2e1561c9220fef212b9a63395d6d8dd5d5aef23a..3a43af9f7061f24fb01a7ba2b10ad9fa8fbdf680 100644 (file)
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -70,29 +70,9 @@ bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags)
 
 void __io_put_kbuf(struct io_kiocb *req, int len, unsigned issue_flags)
 {
-       /*
-        * 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 (issue_flags & IO_URING_F_UNLOCKED) {
-               struct io_ring_ctx *ctx = req->ctx;
-
-               spin_lock(&ctx->completion_lock);
-               __io_put_kbuf_list(req, len, &ctx->io_buffers_comp);
-               spin_unlock(&ctx->completion_lock);
-       } else {
-               lockdep_assert_held(&req->ctx->uring_lock);
-
-               __io_put_kbuf_list(req, len, &req->ctx->io_buffers_cache);
-       }
+       spin_lock(&req->ctx->completion_lock);
+       __io_put_kbuf_list(req, len);
+       spin_unlock(&req->ctx->completion_lock);
 }
 
 static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len,

diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h
index 310f94a0727a6f1bcdbce88c058edf835d808e44..1f2877064829804b7e02af437a359db57d196a8a 100644 (file)
--- a/io_uring/kbuf.h
+++ b/io_uring/kbuf.h
@@ -160,14 +160,13 @@ static inline bool __io_put_kbuf_ring(struct io_kiocb *req, int len, int nr)
        return ret;
 }
 
-static inline void __io_put_kbuf_list(struct io_kiocb *req, int len,
-                                     struct list_head *list)
+static inline void __io_put_kbuf_list(struct io_kiocb *req, int len)
 {
        if (req->flags & REQ_F_BUFFER_RING) {
                __io_put_kbuf_ring(req, len, 1);
        } else {
                req->buf_index = req->kbuf->bgid;
-               list_add(&req->kbuf->list, list);
+               list_add(&req->kbuf->list, &req->ctx->io_buffers_comp);
                req->flags &= ~REQ_F_BUFFER_SELECTED;
        }
 }
@@ -179,7 +178,7 @@ static inline void io_kbuf_drop(struct io_kiocb *req)
 
        spin_lock(&req->ctx->completion_lock);
        /* len == 0 is fine here, non-ring will always drop all of it */
-       __io_put_kbuf_list(req, 0, &req->ctx->io_buffers_comp);
+       __io_put_kbuf_list(req, 0);
        spin_unlock(&req->ctx->completion_lock);
 }