From c1c87c2ba9ec06d8ba9e8a26c18c67a2ba9cd9c1 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 4 Aug 2016 16:10:01 +0200 Subject: [PATCH] loop: make do_req_filebacked more robust Use a switch statement to iterate over the possible operations and error out if it's an incorrect one. Signed-off-by: Jens Axboe --- drivers/block/loop.c | 55 ++++++++++++++++++-------------------------- 1 file changed, 22 insertions(+), 33 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 91c2c881cb49..c9f2107f7095 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -510,14 +510,10 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, return 0; } - -static inline int lo_rw_simple(struct loop_device *lo, - struct request *rq, loff_t pos, bool rw) +static int do_req_filebacked(struct loop_device *lo, struct request *rq) { struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); - - if (cmd->use_aio) - return lo_rw_aio(lo, cmd, pos, rw); + loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; /* * lo_write_simple and lo_read_simple should have been covered @@ -528,37 +524,30 @@ static inline int lo_rw_simple(struct loop_device *lo, * of the req at one time. And direct read IO doesn't need to * run flush_dcache_page(). */ - if (rw == WRITE) - return lo_write_simple(lo, rq, pos); - else - return lo_read_simple(lo, rq, pos); -} - -static int do_req_filebacked(struct loop_device *lo, struct request *rq) -{ - loff_t pos; - int ret; - - pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; - - if (op_is_write(req_op(rq))) { - if (req_op(rq) == REQ_OP_FLUSH) - ret = lo_req_flush(lo, rq); - else if (req_op(rq) == REQ_OP_DISCARD) - ret = lo_discard(lo, rq, pos); - else if (lo->transfer) - ret = lo_write_transfer(lo, rq, pos); + switch (req_op(rq)) { + case REQ_OP_FLUSH: + return lo_req_flush(lo, rq); + case REQ_OP_DISCARD: + return lo_discard(lo, rq, pos); + case REQ_OP_WRITE: + if (lo->transfer) + return lo_write_transfer(lo, rq, pos); + else if (cmd->use_aio) + return lo_rw_aio(lo, cmd, pos, WRITE); else - ret = lo_rw_simple(lo, rq, pos, WRITE); - - } else { + return lo_write_simple(lo, rq, pos); + case REQ_OP_READ: if (lo->transfer) - ret = lo_read_transfer(lo, rq, pos); + return lo_read_transfer(lo, rq, pos); + else if (cmd->use_aio) + return lo_rw_aio(lo, cmd, pos, READ); else - ret = lo_rw_simple(lo, rq, pos, READ); + return lo_read_simple(lo, rq, pos); + default: + WARN_ON_ONCE(1); + return -EIO; + break; } - - return ret; } struct switch_request { -- 2.20.1