[PATCH 05/18] ataflop: dequeue and track in-flight request

Tejun Heo
2009-05-08T02:58:32Z

ataflop has single request in flight. Till now, whenever it needs to
access the in-flight request it called elv_next_request(). This patch
makes ataflop track the in-flight request directly and dequeue it when
processing starts. The added complexity is minimal and this will help
future block layer changes.

[ Impact: dequeue in-flight request, one elv_next_request() per request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
---
drivers/block/ataflop.c | 63 ++++++++++++++++++++++++++---------------------
1 files changed, 35 insertions(+), 28 deletions(-)

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index 234024c..89a591d 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -79,9 +79,7 @@
#undef DEBUG

static struct request_queue *floppy_queue;
-
-#define QUEUE (floppy_queue)
-#define CURRENT elv_next_request(floppy_queue)
+static struct request *fd_request;

/* Disk types: DD, HD, ED */
static struct atari_disk_type {
@@ -376,6 +374,12 @@ static DEFINE_TIMER(readtrack_timer, fd_readtrack_check, 0, 0);
static DEFINE_TIMER(timeout_timer, fd_times_out, 0, 0);
static DEFINE_TIMER(fd_timer, check_change, 0, 0);

+static void fd_end_request_cur(int err)
+{
+ if (!__blk_end_request_cur(fd_request, err))
+ fd_request = NULL;
+}
+
static inline void start_motor_off_timer(void)
{
mod_timer(&motor_off_timer, jiffies + FD_MOTOR_OFF_DELAY);
@@ -606,15 +610,15 @@ static void fd_error( void )
return;
}

- if (!CURRENT)
+ if (!fd_request)
return;

- CURRENT->errors++;
- if (CURRENT->errors >= MAX_ERRORS) {
+ fd_request->errors++;
+ if (fd_request->errors >= MAX_ERRORS) {
printk(KERN_ERR "fd%d: too many errors.\n", SelectedDrive );
- __blk_end_request_cur(CURRENT, -EIO);
+ fd_end_request_cur(-EIO);
}
- else if (CURRENT->errors == RECALIBRATE_ERRORS) {
+ else if (fd_request->errors == RECALIBRATE_ERRORS) {
printk(KERN_WARNING "fd%d: recalibrating\n", SelectedDrive );
if (SelectedDrive != -1)
SUD.track = -1;
@@ -725,14 +729,14 @@ static void do_fd_action( int drive )
if (IS_BUFFERED( drive, ReqSide, ReqTrack )) {
if (ReqCmd == READ) {
copy_buffer( SECTOR_BUFFER(ReqSector), ReqData );
- if (++ReqCnt < blk_rq_cur_sectors(CURRENT)) {
+ if (++ReqCnt < blk_rq_cur_sectors(fd_request)) {
/* read next sector */
setup_req_params( drive );
goto repeat;
}
else {
/* all sectors finished */
- __blk_end_request_cur(CURRENT, 0);
+ fd_end_request_cur(0);
redo_fd_request();
return;
}
@@ -1130,14 +1134,14 @@ static void fd_rwsec_done1(int status)
}
}

- if (++ReqCnt < blk_rq_cur_sectors(CURRENT)) {
+ if (++ReqCnt < blk_rq_cur_sectors(fd_request)) {
/* read next sector */
setup_req_params( SelectedDrive );
do_fd_action( SelectedDrive );
}
else {
/* all sectors finished */
- __blk_end_request_cur(CURRENT, 0);
+ fd_end_request_cur(0);
redo_fd_request();
}
return;
@@ -1378,7 +1382,7 @@ static void setup_req_params( int drive )
ReqData = ReqBuffer + 512 * ReqCnt;

if (UseTrackbuffer)
- read_track = (ReqCmd == READ && CURRENT->errors == 0);
+ read_track = (ReqCmd == READ && fd_request->errors == 0);
else
read_track = 0;

@@ -1392,25 +1396,28 @@ static void redo_fd_request(void)
int drive, type;
struct atari_floppy_struct *floppy;

- DPRINT(("redo_fd_request: CURRENT=%p dev=%s CURRENT->sector=%ld\n",
- CURRENT, CURRENT ? CURRENT->rq_disk->disk_name : "",
- CURRENT ? blk_rq_pos(CURRENT) : 0 ));
+ DPRINT(("redo_fd_request: fd_request=%p dev=%s fd_request->sector=%ld\n",
+ fd_request, fd_request ? fd_request->rq_disk->disk_name : "",
+ fd_request ? blk_rq_pos(fd_request) : 0 ));

IsFormatting = 0;

repeat:
+ if (!fd_request) {
+ fd_request = elv_next_request(floppy_queue);
+ if (!fd_request)
+ goto the_end;
+ blkdev_dequeue_request(fd_request);
+ }

- if (!CURRENT)
- goto the_end;
-
- floppy = CURRENT->rq_disk->private_data;
+ floppy = fd_request->rq_disk->private_data;
drive = floppy - unit;
type = floppy->type;

if (!UD.connected) {
/* drive not connected */
printk(KERN_ERR "Unknown Device: fd%d\n", drive );
- __blk_end_request_cur(CURRENT, -EIO);
+ fd_end_request_cur(-EIO);
goto repeat;
}

@@ -1426,12 +1433,12 @@ repeat:
/* user supplied disk type */
if (--type >= NUM_DISK_MINORS) {
printk(KERN_WARNING "fd%d: invalid disk format", drive );
- __blk_end_request_cur(CURRENT, -EIO);
+ fd_end_request_cur(-EIO);
goto repeat;
}
if (minor2disktype[type].drive_types > DriveType) {
printk(KERN_WARNING "fd%d: unsupported disk format", drive );
- __blk_end_request_cur(CURRENT, -EIO);
+ fd_end_request_cur(-EIO);
goto repeat;
}
type = minor2disktype[type].index;
@@ -1440,8 +1447,8 @@ repeat:
UD.autoprobe = 0;
}

- if (blk_rq_pos(CURRENT) + 1 > UDT->blocks) {
- __blk_end_request_cur(CURRENT, -EIO);
+ if (blk_rq_pos(fd_request) + 1 > UDT->blocks) {
+ fd_end_request_cur(-EIO);
goto repeat;
}

@@ -1449,9 +1456,9 @@ repeat:
del_timer( &motor_off_timer );

ReqCnt = 0;
- ReqCmd = rq_data_dir(CURRENT);
- ReqBlock = blk_rq_pos(CURRENT);
- ReqBuffer = CURRENT->buffer;
+ ReqCmd = rq_data_dir(fd_request);
+ ReqBlock = blk_rq_pos(fd_request);
+ ReqBuffer = fd_request->buffer;
setup_req_params( drive );
do_fd_action( drive );

--
1.6.0.2