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

From: Sergei Shtylyov
Date: Sat May 16 2009 - 09:42:38 EST


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@xxxxxxxxxx>
Cc: Laurent Vivier <Laurent@xxxxxxxxxxxx>
---
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


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