2024-02-13 10:25:19

by Arnd Bergmann

Subject: [PATCH] floppy: fix function pointer cast warnings

From: Arnd Bergmann <[email protected]>

clang-16 complains about a control flow integrity (kcfi) violation
casting between incompatible pointers:

drivers/block/floppy.c:2001:11: error: cast from 'void (*)(void)' to 'done_f' (aka 'void (*)(int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
2001 | .done = (done_f)empty
| ^~~~~~~~~~~~~

Just add another empty function with the correct prototype as a
workaround.

The warning is for code that was added before the start of the normal
git history, but I tracked it done to an early change in the reconstructed
linux-history.git.

Fixes: 598a477afe06 ("Import 1.1.41")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/block/floppy.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index d0e41d52d6a9..2ba0ba135951 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -530,14 +530,13 @@ static struct format_descr format_req;
static char *floppy_track_buffer;
static int max_buffer_sectors;

-typedef void (*done_f)(int);
static const struct cont_t {
void (*interrupt)(void);
/* this is called after the interrupt of the
* main command */
void (*redo)(void); /* this is called to retry the operation */
void (*error)(void); /* this is called to tally an error */
- done_f done; /* this is called to say if the operation has
+ void (*done)(int); /* this is called to say if the operation has
* succeeded/failed */
} *cont;

@@ -985,6 +984,10 @@ static void empty(void)
{
}

+static void empty_done(int result)
+{
+}
+
static void (*floppy_work_fn)(void);

static void floppy_work_workfn(struct work_struct *work)
@@ -1998,14 +2001,14 @@ static const struct cont_t wakeup_cont = {
.interrupt = empty,
.redo = do_wakeup,
.error = empty,
- .done = (done_f)empty
+ .done = empty_done,
};

static const struct cont_t intr_cont = {
.interrupt = empty,
.redo = process_fd_request,
.error = empty,
- .done = (done_f)empty
+ .done = empty_done,
};

/* schedules handler, waiting for completion. May be interrupted, will then
--
2.39.2

2024-02-13 15:56:30

by Jens Axboe

Subject: Re: [PATCH] floppy: fix function pointer cast warnings

On Tue, 13 Feb 2024 10:59:07 +0100, Arnd Bergmann wrote:
> clang-16 complains about a control flow integrity (kcfi) violation
> casting between incompatible pointers:
>
> drivers/block/floppy.c:2001:11: error: cast from 'void (*)(void)' to 'done_f' (aka 'void (*)(int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
> 2001 | .done = (done_f)empty
> | ^~~~~~~~~~~~~
>
> [...]

Applied, thanks!

[1/1] floppy: fix function pointer cast warnings
commit: 7789bf05529889a39bcf4cd17a68521de063b88b

Best regards,
--
Jens Axboe