Re: [PATCH 11/18] swim: dequeue in-flight request

Sergei Shtylyov
2009-05-16T13:42:34Z

Hello.

Tejun Heo wrote:

> swim processes requests one-by-one synchronously and can easily be
> converted to dequeuing model. Convert it.
>
> [ Impact: dequeue in-flight request ]
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Laurent Vivier <Laurent@lvivier.info>
> ---
> drivers/block/swim.c | 47 +++++++++++++++++++++++------------------------
> 1 files changed, 23 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/block/swim.c b/drivers/block/swim.c
> index fc6a1c3..dedd489 100644
> --- a/drivers/block/swim.c
> +++ b/drivers/block/swim.c
> @@ -514,7 +514,7 @@ static int floppy_read_sectors(struct floppy_state *fs,
> ret = swim_read_sector(fs, side, track, sector,
> buffer);
> if (try-- == 0)
> - return -1;
> + return -EIO;
> } while (ret != 512);
>
> buffer += ret;
> @@ -528,38 +528,37 @@ static void redo_fd_request(struct request_queue *q)
> struct request *req;
> struct floppy_state *fs;
>
> - while ((req = elv_next_request(q))) {
> + req = elv_next_request(q);
> + if (req)
> + blkdev_dequeue_request(req);
> +
> + while (req) {
> + int err = -EIO;
>
> fs = req->rq_disk->private_data;
> - if (blk_rq_pos(req) >= fs->total_secs) {
> - __blk_end_request_cur(req, -EIO);
> - continue;
> - }
> - if (!fs->disk_in) {
> - __blk_end_request_cur(req, -EIO);
> - continue;
> - }
> - if (rq_data_dir(req) == WRITE) {
> - if (fs->write_protected) {
> - __blk_end_request_cur(req, -EIO);
> - continue;
> - }
> - }
> + if (blk_rq_pos(req) >= fs->total_secs)
> + goto done;
> + if (!fs->disk_in)
> + goto done;
> + if (rq_data_dir(req) == WRITE && fs->write_protected)
> + goto done;
> +
> switch (rq_data_dir(req)) {
> case WRITE:
> /* NOT IMPLEMENTED */
> - __blk_end_request_cur(req, -EIO);
> break;
> case READ:
> - if (floppy_read_sectors(fs, blk_rq_pos(req),
> - blk_rq_cur_sectors(req),
> - req->buffer)) {
> - __blk_end_request_cur(req, -EIO);
> - continue;
> - }
> - __blk_end_request_cur(req, 0);
> + err = floppy_read_sectors(fs, blk_rq_pos(req),
> + blk_rq_cur_sectors(req),
> + req->buffer);
> break;
> }
> + done:
> + if (!__blk_end_request_cur(req, err)) {
> + req = elv_next_request(q);
> + if (req)
> + blkdev_dequeue_request(req);
> + }
> }
> }

And without duplication:

@@ -528,38 +528,37 @@
static void redo_fd_request(struct request_queue *q)
{
- struct request *req;
struct floppy_state *fs;

- while ((req = elv_next_request(q))) {
+ while (1) {
+ struct request *req = elv_next_request(q);
+ int err;
+
+ if (req == NULL)
+ break;
+ blkdev_dequeue_request(req);

+again:
+ err = -EIO;
fs = req->rq_disk->private_data;
- if (blk_rq_pos(req) >= fs->total_secs) {
- __blk_end_request_cur(req, -EIO);
- continue;
- }
- if (!fs->disk_in) {
- __blk_end_request_cur(req, -EIO);
- continue;
- }
- if (rq_data_dir(req) == WRITE) {
- if (fs->write_protected) {
- __blk_end_request_cur(req, -EIO);
- continue;
- }
- }
+ if (blk_rq_pos(req) >= fs->total_secs)
+ goto done;
+ if (!fs->disk_in)
+ goto done;
+ if (rq_data_dir(req) == WRITE && fs->write_protected)
+ goto done;
+
switch (rq_data_dir(req)) {
case WRITE:
/* NOT IMPLEMENTED */
- __blk_end_request_cur(req, -EIO);
break;
case READ:
- if (floppy_read_sectors(fs, blk_rq_pos(req),
- blk_rq_cur_sectors(req),
- req->buffer)) {
- __blk_end_request_cur(req, -EIO);
- continue;
- }
- __blk_end_request_cur(req, 0);
+ err = floppy_read_sectors(fs, blk_rq_pos(req),
+ blk_rq_cur_sectors(req),
+ req->buffer);
break;
}
+ done:
+ if (__blk_end_request_cur(req, err))
+ goto again;
}
}

MBR, Sergei