io_uring/mock: add cmd using vectored regbufs

There is a command api allowing to import vectored registered buffers,
add a new mock command that uses the feature and simply copies the
specified registered buffer into user space or vice versa.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/229a113fd7de6b27dbef9567f7c0bf4475c9017d.1750599274.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/uapi/linux/io_uring/mock_file.h b/include/uapi/linux/io_uring/mock_file.h
index a44273fd526d9090d0151d8aa1dd4f0c8ef399ea..73aca477d5c803be8319bec6ba0b1dcb9f3836e0 100644 (file)
--- a/include/uapi/linux/io_uring/mock_file.h
+++ b/include/uapi/linux/io_uring/mock_file.h
@@ -3,6 +3,12 @@
 
 #include <linux/types.h>
 
+enum {
+       IORING_MOCK_FEAT_CMD_COPY,
+
+       IORING_MOCK_FEAT_END,
+};
+
 struct io_uring_mock_probe {
        __u64           features;
        __u64           __resv[9];
@@ -19,4 +25,12 @@ enum {
        IORING_MOCK_MGR_CMD_CREATE,
 };
 
+enum {
+       IORING_MOCK_CMD_COPY_REGBUF,
+};
+
+enum {
+       IORING_MOCK_COPY_FROM                   = 1,
+};
+
 #endif

diff --git a/io_uring/mock_file.c b/io_uring/mock_file.c
index 3681d0b8d8de588352986a2d63bc6dd657d81326..8285393f4a5b7a24587afe6b69032b6982e0d50a 100644 (file)
--- a/io_uring/mock_file.c
+++ b/io_uring/mock_file.c
@@ -9,8 +9,76 @@
 #include <linux/io_uring_types.h>
 #include <uapi/linux/io_uring/mock_file.h>
 
+#define IO_VALID_COPY_CMD_FLAGS                IORING_MOCK_COPY_FROM
+
+static int io_copy_regbuf(struct iov_iter *reg_iter, void __user *ubuf)
+{
+       size_t ret, copied = 0;
+       size_t buflen = PAGE_SIZE;
+       void *tmp_buf;
+
+       tmp_buf = kzalloc(buflen, GFP_KERNEL);
+       if (!tmp_buf)
+               return -ENOMEM;
+
+       while (iov_iter_count(reg_iter)) {
+               size_t len = min(iov_iter_count(reg_iter), buflen);
+
+               if (iov_iter_rw(reg_iter) == ITER_SOURCE) {
+                       ret = copy_from_iter(tmp_buf, len, reg_iter);
+                       if (ret <= 0)
+                               break;
+                       if (copy_to_user(ubuf, tmp_buf, ret))
+                               break;
+               } else {
+                       if (copy_from_user(tmp_buf, ubuf, len))
+                               break;
+                       ret = copy_to_iter(tmp_buf, len, reg_iter);
+                       if (ret <= 0)
+                               break;
+               }
+               ubuf += ret;
+               copied += ret;
+       }
+
+       kfree(tmp_buf);
+       return copied;
+}
+
+static int io_cmd_copy_regbuf(struct io_uring_cmd *cmd, unsigned int issue_flags)
+{
+       const struct io_uring_sqe *sqe = cmd->sqe;
+       const struct iovec __user *iovec;
+       unsigned flags, iovec_len;
+       struct iov_iter iter;
+       void __user *ubuf;
+       int dir, ret;
+
+       ubuf = u64_to_user_ptr(READ_ONCE(sqe->addr3));
+       iovec = u64_to_user_ptr(READ_ONCE(sqe->addr));
+       iovec_len = READ_ONCE(sqe->len);
+       flags = READ_ONCE(sqe->file_index);
+
+       if (unlikely(sqe->ioprio || sqe->__pad1))
+               return -EINVAL;
+       if (flags & ~IO_VALID_COPY_CMD_FLAGS)
+               return -EINVAL;
+
+       dir = (flags & IORING_MOCK_COPY_FROM) ? ITER_SOURCE : ITER_DEST;
+       ret = io_uring_cmd_import_fixed_vec(cmd, iovec, iovec_len, dir, &iter,
+                                           issue_flags);
+       if (ret)
+               return ret;
+       ret = io_copy_regbuf(&iter, ubuf);
+       return ret ? ret : -EFAULT;
+}
+
 static int io_mock_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
 {
+       switch (cmd->cmd_op) {
+       case IORING_MOCK_CMD_COPY_REGBUF:
+               return io_cmd_copy_regbuf(cmd, issue_flags);
+       }
        return -ENOTSUPP;
 }
 
@@ -91,7 +159,7 @@ static int io_probe_mock(struct io_uring_cmd *cmd)
        if (!mem_is_zero(&mp, sizeof(mp)))
                return -EINVAL;
 
-       mp.features = 0;
+       mp.features = IORING_MOCK_FEAT_END;
 
        if (copy_to_user(uarg, &mp, uarg_size))
                return -EFAULT;