On 3/18/25 01:58, Sidong Yang wrote:
On Mon, Mar 17, 2025 at 09:40:05AM -0600, Jens Axboe wrote:
On 3/17/25 7:57 AM, Sidong Yang wrote:
This patch introduces btrfs_uring_import_iovec(). In encoded read/write
with uring cmd, it uses import_iovec without supporting fixed buffer.
btrfs_using_import_iovec() could use fixed buffer if cmd flags has
IORING_URING_CMD_FIXED.
Signed-off-by: Sidong Yang <sidong.yang@xxxxxxxxxx>
---
fs/btrfs/ioctl.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6c18bad53cd3..a7b52fd99059 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4802,6 +4802,28 @@ struct btrfs_uring_encoded_data {
struct iov_iter iter;
};
+static int btrfs_uring_import_iovec(struct io_uring_cmd *cmd,
+ unsigned int issue_flags, int rw)
+{
+ struct btrfs_uring_encoded_data *data =
+ io_uring_cmd_get_async_data(cmd)->op_data;
+ int ret;
+
+ if (cmd && (cmd->flags & IORING_URING_CMD_FIXED)) {
+ data->iov = NULL;
+ ret = io_uring_cmd_import_fixed_vec(cmd, data->args.iov,
+ data->args.iovcnt,
+ ITER_DEST, issue_flags,
+ &data->iter);
+ } else {
+ data->iov = data->iovstack;
+ ret = import_iovec(rw, data->args.iov, data->args.iovcnt,
+ ARRAY_SIZE(data->iovstack), &data->iov,
+ &data->iter);
+ }
+ return ret;
+}
How can 'cmd' be NULL here?
It seems that there is no checkes for 'cmd' before and it works same as before.
But I think it's better to add a check in function start for safety.
The check goes two lines after you already dereferenced it, and it
seems to be called from io_uring cmd specific code. The null check
only adds to confusion.
--
Pavel Begunkov
