linux.git/drivers/block/ataflop.c, branch v5.10.258

block: ataflop: more blk-mq refactoring fixes

2024-03-01T12:16:51+00:00

commit d28e4dff085c5a87025c9a0a85fb798bd8e9ca17 upstream.

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 
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 
[MSch: v5.10 backport merge conflict fix]
Signed-off-by: Greg Kroah-Hartman

block: ataflop: fix breakage introduced at blk-mq refactoring

2024-03-01T12:16:46+00:00

[ Upstream commit 86d46fdaa12ae5befc16b8d73fc85a3ca0399ea6 ]

Refactoring of the Atari floppy driver when converting to blk-mq
has broken the state machine in not-so-subtle ways:

finish_fdc() must be called when operations on the floppy device
have completed. This is crucial in order to relase the ST-DMA
lock, which protects against concurrent access to the ST-DMA
controller by other drivers (some DMA related, most just related
to device register access - broken beyond compare, I know).

When rewriting the driver's old do_request() function, the fact
that finish_fdc() was called only when all queued requests had
completed appears to have been overlooked. Instead, the new
request function calls finish_fdc() immediately after the last
request has been queued. finish_fdc() executes a dummy seek after
most requests, and this overwrites the state machine's interrupt
hander that was set up to wait for completion of the read/write
request just prior. To make matters worse, finish_fdc() is called
before device interrupts are re-enabled, making certain that the
read/write interupt is missed.

Shifting the finish_fdc() call into the read/write request
completion handler ensures the driver waits for the request to
actually complete. With a queue depth of 2, we won't see long
request sequences, so calling finish_fdc() unconditionally just
adds a little overhead for the dummy seeks, and keeps the code
simple.

While we're at it, kill ataflop_commit_rqs() which does nothing
but run finish_fdc() unconditionally, again likely wiping out an
in-flight request.

Signed-off-by: Michael Schmitz 
Fixes: 6ec3938cff95 ("ataflop: convert to blk-mq")
CC: linux-block@vger.kernel.org
CC: Tetsuo Handa 
Link: https://lore.kernel.org/r/20211019061321.26425-1-schmitzmic@gmail.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

ataflop: use bdev_check_media_change

2020-09-10T15:32:30+00:00

Switch to use bdev_check_media_change instead of check_disk_change and
call floppy_revalidate manually.  Given that floppy_revalidate only
deals with media change events, the extra call into ->revalidate_disk
from bdev_disk_changed is not required either, so stop wiring up the
method.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Jens Axboe

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

ataflop: Remove unneeded semicolon

2019-11-28T17:40:47+00:00

Fixes coccicheck warning:

drivers/block/ataflop.c:860:53-54: Unneeded semicolon

Reported-by: Hulk Robot 
Signed-off-by: zhengbin 
Signed-off-by: Jens Axboe

ataflop: Mark expected switch fall-through

2019-07-29T21:24:58+00:00

Mark switch cases where we are expecting to fall through.

This patch fixes the following warning (Building: m68k):

drivers/block/ataflop.c: In function ‘fd_locked_ioctl’:
drivers/block/ataflop.c:1728:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   set_capacity(floppy->disk, MAX_DISK_SIZE * 2);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/block/ataflop.c:1729:2: note: here
  case FDFMTEND:
  ^~~~

Signed-off-by: Gustavo A. R. Silva 
Signed-off-by: Jens Axboe

treewide: Add SPDX license identifier for more missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have MODULE_LICENCE("GPL*") inside which was used in the initial
   scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

Revert "block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers"

2019-04-12T19:35:27+00:00

This reverts commit 9fd097b14918875bd6f125ed699d7bbbba5893ee.

Instead of leaving disk->events completely empty, we now export the
supported events again, and tell the block layer not to forward events to
user space by not setting DISK_EVENT_FLAG_UEVENT. This allows the block
layer to distinguish between devices that for which events should be
handled in kernel only, and devices which don't support any meda change
events at all.

Cc: Jiri Kosina 
Cc: Tim Waugh 
Cc: Michal Simek 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Martin Wilck 
Signed-off-by: Jens Axboe

ataflop: implement mq_ops->commit_rqs() hook

2018-11-29T17:12:27+00:00

We need this for blk-mq to kick things into gear, if we told it that
we had more IO coming, but then failed to deliver on that promise.

Reviewed-by: Omar Sandoval 
Reviewed-by: Ming Lei 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

ataflop: fix error handling in atari_floppy_init()

2018-11-29T15:16:06+00:00

Smatch complains that there is an off by one if the allocation fails in:

	DMABuffer = atari_stram_alloc(BUFFER_SIZE+512, "ataflop");

In that situation, "i" would be point to one element beyond the end of
the unit[] array.

There is a second bug because the error handling calls
blk_mq_free_tag_set(&unit[i].tag_set); regardless of whether
"disk->queue" is NULL or non-NULL.  So if blk_mq_init_sq_queue() fails,
then that means unit[i].tag_set->tags is NULL and it leads to an Oops.

It's easiest to call put_disk() before the goto to clean up the partial
iteration.  Then the earlier unit[] elements are fully allocated so we
can remove the checks whether "disk->queue" is NULL and the code is
simpler.

Signed-off-by: Dan Carpenter 
Signed-off-by: Jens Axboe