[PATCH 5.15 517/917] block: ataflop: more blk-mq refactoring fixes

Greg Kroah-Hartman
2021-11-15T23:42:44Z

From: Michael Schmitz <schmitzmic@gmail.com>

[ Upstream commit d28e4dff085c5a87025c9a0a85fb798bd8e9ca17 ]

As it turns out, my earlier patch in commit 86d46fdaa12a (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 <schmitzmic@gmail.com>
Fixes: 6ec3938cff95f (ataflop: convert to blk-mq)
CC: linux-block@vger.kernel.org
Link: https://lore.kernel.org/r/20211024002013.9332-1-schmitzmic@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/ataflop.c | 45 +++++++++++++++++++++++++++++++++++------
1 file changed, 39 insertions(+), 6 deletions(-)

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index bbb64331cf8f4..4947e41f89b7d 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -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;
}
}

@@ -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 );
}

@@ -729,8 +748,10 @@ static int do_format(int drive, int type, struct atari_format_descr *desc)
if (type) {
type--;
if (type >= NUM_DISK_MINORS ||
- minor2disktype[type].drive_types > DriveType)
+ minor2disktype[type].drive_types > DriveType) {
+ finish_fdc();
return -EINVAL;
+ }
}

q = unit[drive].disk[type]->queue;
@@ -748,6 +769,7 @@ 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;
}
@@ -788,6 +810,7 @@ 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);
@@ -822,6 +845,7 @@ static void do_fd_action( int drive )
else {
/* all sectors finished */
fd_end_request_cur(BLK_STS_OK);
+ finish_fdc();
return;
}
}
@@ -1225,8 +1249,8 @@ static void fd_rwsec_done1(int status)
}
else {
/* all sectors finished */
- finish_fdc();
fd_end_request_cur(BLK_STS_OK);
+ finish_fdc();
}
return;

@@ -1348,7 +1372,7 @@ 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 {
@@ -1383,7 +1407,8 @@ 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"));
@@ -1480,7 +1505,9 @@ 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) {
@@ -1502,6 +1529,7 @@ 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;
}

@@ -1518,11 +1546,13 @@ 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;
@@ -1623,6 +1653,7 @@ 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;
}

@@ -1690,8 +1721,10 @@ 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(disk, UDT->blocks);
--
2.33.0