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block: ataflop: more blk-mq refactoring fixes
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commit d28e4df upstream.

As it turns out, my earlier patch in commit 86d46fd (block:
ataflop: fix breakage introduced at blk-mq refactoring) was
incomplete. This patch fixes any remaining issues found during
more testing and code review.

Requests exceeding 4 k are handled in 4k segments but
__blk_mq_end_request() is never called on these (still
sectors outstanding on the request). With redo_fd_request()
removed, there is no provision to kick off processing of the
next segment, causing requests exceeding 4k to hang. (By
setting /sys/block/fd0/queue/max_sectors_k <= 4 as workaround,
this behaviour can be avoided).

Instead of reintroducing redo_fd_request(), requeue the remainder
of the request by calling blk_mq_requeue_request() on incomplete
requests (i.e. when blk_update_request() still returns true), and
rely on the block layer to queue the residual as new request.

Both error handling and formatting needs to release the
ST-DMA lock, so call finish_fdc() on these (this was previously
handled by redo_fd_request()). finish_fdc() may be called
legitimately without the ST-DMA lock held - make sure we only
release the lock if we actually held it. In a similar way,
early exit due to errors in ataflop_queue_rq() must release
the lock.

After minor errors, fd_error sets up to recalibrate the drive
but never re-runs the current operation (another task handled by
redo_fd_request() before). Call do_fd_action() to get the next
steps (seek, retry read/write) underway.

Signed-off-by: Michael Schmitz <[email protected]>
Fixes: 6ec3938 (ataflop: convert to blk-mq)
CC: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
[MSch: v5.10 backport merge conflict fix]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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@gregkh
Michael Schmitz authored and gregkh committed Mar 1, 2024
1 parent b49b022 commit bff0a06
Showing 1 changed file with 37 additions and 5 deletions.
42 changes: 37 additions & 5 deletions drivers/block/ataflop.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -456,10 +456,20 @@ static DEFINE_TIMER(fd_timer, check_change);

static void fd_end_request_cur(blk_status_t err)
{
DPRINT(("fd_end_request_cur(), bytes %d of %d\n",
blk_rq_cur_bytes(fd_request),
blk_rq_bytes(fd_request)));

if (!blk_update_request(fd_request, err,
blk_rq_cur_bytes(fd_request))) {
DPRINT(("calling __blk_mq_end_request()\n"));
__blk_mq_end_request(fd_request, err);
fd_request = NULL;
} else {
/* requeue rest of request */
DPRINT(("calling blk_mq_requeue_request()\n"));
blk_mq_requeue_request(fd_request, true);
fd_request = NULL;
}
}

Expand Down Expand Up @@ -697,12 +707,21 @@ static void fd_error( void )
if (fd_request->error_count >= MAX_ERRORS) {
printk(KERN_ERR "fd%d: too many errors.\n", SelectedDrive );
fd_end_request_cur(BLK_STS_IOERR);
finish_fdc();
return;
}
else if (fd_request->error_count == RECALIBRATE_ERRORS) {
printk(KERN_WARNING "fd%d: recalibrating\n", SelectedDrive );
if (SelectedDrive != -1)
SUD.track = -1;
}
/* need to re-run request to recalibrate */
atari_disable_irq( IRQ_MFP_FDC );

setup_req_params( SelectedDrive );
do_fd_action( SelectedDrive );

atari_enable_irq( IRQ_MFP_FDC );
}


Expand Down Expand Up @@ -737,6 +756,7 @@ static int do_format(int drive, int type, struct atari_format_descr *desc)
if (type) {
if (--type >= NUM_DISK_MINORS ||
minor2disktype[type].drive_types > DriveType) {
finish_fdc();
ret = -EINVAL;
goto out;
}
Expand All @@ -745,6 +765,7 @@ static int do_format(int drive, int type, struct atari_format_descr *desc)
}

if (!UDT || desc->track >= UDT->blocks/UDT->spt/2 || desc->head >= 2) {
finish_fdc();
ret = -EINVAL;
goto out;
}
Expand Down Expand Up @@ -785,6 +806,7 @@ static int do_format(int drive, int type, struct atari_format_descr *desc)

wait_for_completion(&format_wait);

finish_fdc();
ret = FormatError ? -EIO : 0;
out:
blk_mq_unquiesce_queue(q);
Expand Down Expand Up @@ -819,6 +841,7 @@ static void do_fd_action( int drive )
else {
/* all sectors finished */
fd_end_request_cur(BLK_STS_OK);
finish_fdc();
return;
}
}
Expand Down Expand Up @@ -1222,8 +1245,8 @@ static void fd_rwsec_done1(int status)
}
else {
/* all sectors finished */
finish_fdc();
fd_end_request_cur(BLK_STS_OK);
finish_fdc();
}
return;

Expand Down Expand Up @@ -1345,7 +1368,7 @@ static void fd_times_out(struct timer_list *unused)

static void finish_fdc( void )
{
if (!NeedSeek) {
if (!NeedSeek || !stdma_is_locked_by(floppy_irq)) {
finish_fdc_done( 0 );
}
else {
Expand Down Expand Up @@ -1380,7 +1403,8 @@ static void finish_fdc_done( int dummy )
start_motor_off_timer();

local_irq_save(flags);
stdma_release();
if (stdma_is_locked_by(floppy_irq))
stdma_release();
local_irq_restore(flags);

DPRINT(("finish_fdc() finished\n"));
Expand Down Expand Up @@ -1477,7 +1501,9 @@ static blk_status_t ataflop_queue_rq(struct blk_mq_hw_ctx *hctx,
int drive = floppy - unit;
int type = floppy->type;

DPRINT(("Queue request: drive %d type %d last %d\n", drive, type, bd->last));
DPRINT(("Queue request: drive %d type %d sectors %d of %d last %d\n",
drive, type, blk_rq_cur_sectors(bd->rq),
blk_rq_sectors(bd->rq), bd->last));

spin_lock_irq(&ataflop_lock);
if (fd_request) {
Expand All @@ -1499,6 +1525,7 @@ static blk_status_t ataflop_queue_rq(struct blk_mq_hw_ctx *hctx,
/* drive not connected */
printk(KERN_ERR "Unknown Device: fd%d\n", drive );
fd_end_request_cur(BLK_STS_IOERR);
stdma_release();
goto out;
}

Expand All @@ -1515,11 +1542,13 @@ static blk_status_t ataflop_queue_rq(struct blk_mq_hw_ctx *hctx,
if (--type >= NUM_DISK_MINORS) {
printk(KERN_WARNING "fd%d: invalid disk format", drive );
fd_end_request_cur(BLK_STS_IOERR);
stdma_release();
goto out;
}
if (minor2disktype[type].drive_types > DriveType) {
printk(KERN_WARNING "fd%d: unsupported disk format", drive );
fd_end_request_cur(BLK_STS_IOERR);
stdma_release();
goto out;
}
type = minor2disktype[type].index;
Expand Down Expand Up @@ -1620,6 +1649,7 @@ static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode,
/* what if type > 0 here? Overwrite specified entry ? */
if (type) {
/* refuse to re-set a predefined type for now */
finish_fdc();
return -EINVAL;
}

Expand Down Expand Up @@ -1687,8 +1717,10 @@ static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode,

/* sanity check */
if (setprm.track != dtp->blocks/dtp->spt/2 ||
setprm.head != 2)
setprm.head != 2) {
finish_fdc();
return -EINVAL;
}

UDT = dtp;
set_capacity(floppy->disk, UDT->blocks);
Expand Down

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