Replace the semi-open coded request list helpers with a proper rq_list type that mirrors the bio_list and has head and tail pointers. Besides better type safety this actually allows to insert at the tail of the list, which will be useful soon. Change-Id: Ia470736d0468c265f5b61cb9d8a0e5544b6b7b0d Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20241113152050.157179-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> Bug: 415836627 (cherry picked from commit a3396b99990d8b4e5797e7b16fdeb64c15ae97bb) Signed-off-by: Bart Van Assche <bvanassche@google.com>