io_uring/kbuf: remove legacy kbuf bulk allocation

Legacy provided buffers are slow and discouraged in favour of the ring
variant. Remove the bulk allocation to keep it simpler as we don't care
about performance.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a064d70370e590efed8076e9501ae4cfc20fe0ca.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 8e72de7712ac97ab16ec228233b74194c9c0b63b..f152afdf0bc7483ce749a3623438e2440696fde3 100644 (file)
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -501,12 +501,9 @@ int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe
        return 0;
 }
 
-#define IO_BUFFER_ALLOC_BATCH 64
-
 static int io_refill_buffer_cache(struct io_ring_ctx *ctx)
 {
-       struct io_buffer *bufs[IO_BUFFER_ALLOC_BATCH];
-       int allocated;
+       struct io_buffer *buf;
 
        /*
         * Completions that don't happen inline (eg not under uring_lock) will
@@ -524,27 +521,10 @@ static int io_refill_buffer_cache(struct io_ring_ctx *ctx)
                spin_unlock(&ctx->completion_lock);
        }
 
-       /*
-        * No free buffers and no completion entries either. Allocate a new
-        * batch of buffer entries and add those to our freelist.
-        */
-
-       allocated = kmem_cache_alloc_bulk(io_buf_cachep, GFP_KERNEL_ACCOUNT,
-                                         ARRAY_SIZE(bufs), (void **) bufs);
-       if (unlikely(!allocated)) {
-               /*
-                * Bulk alloc is all-or-nothing. If we fail to get a batch,
-                * retry single alloc to be on the safe side.
-                */
-               bufs[0] = kmem_cache_alloc(io_buf_cachep, GFP_KERNEL);
-               if (!bufs[0])
-                       return -ENOMEM;
-               allocated = 1;
-       }
-
-       while (allocated)
-               list_add_tail(&bufs[--allocated]->list, &ctx->io_buffers_cache);
-
+       buf = kmem_cache_alloc(io_buf_cachep, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+       list_add_tail(&buf->list, &ctx->io_buffers_cache);
        return 0;
 }