floppy: don't use PREPARE_[DELAYED_]WORK

PREPARE_[DELAYED_]WORK() are being phased out.  They have few users
and a nasty surprise in terms of reentrancy guarantee as workqueue
considers work items to be different if they don't have the same work
function.

floppy has been multiplexing floppy_work and fd_timer with multiple
work functions.  Introduce floppy_work_workfn() and fd_timer_workfn()
which invoke floppy_work_fn and fd_timer_fn respectively and always
use the two functions as the work functions and update the users to
set floppy_work_fn and fd_timer_fn instead of overriding work
functions using PREPARE_[DELAYED_]WORK().

It would probably be best to route this with other related updates
through the workqueue tree.

Lightly tested using qemu.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 28 insertions, 14 deletions

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 2023043ce7c0..8f5565bf34cd 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -961,17 +961,31 @@ static void empty(void)
 {
 }
 
-static DECLARE_WORK(floppy_work, NULL);
+static void (*floppy_work_fn)(void);
+
+static void floppy_work_workfn(struct work_struct *work)
+{
+        floppy_work_fn();
+}
+
+static DECLARE_WORK(floppy_work, floppy_work_workfn);
 
 static void schedule_bh(void (*handler)(void))
 {
         WARN_ON(work_pending(&floppy_work));
 
-        PREPARE_WORK(&floppy_work, (work_func_t)handler);
+        floppy_work_fn = handler;
         queue_work(floppy_wq, &floppy_work);
 }
 
-static DECLARE_DELAYED_WORK(fd_timer, NULL);
+static void (*fd_timer_fn)(void) = NULL;
+
+static void fd_timer_workfn(struct work_struct *work)
+{
+        fd_timer_fn();
+}
+
+static DECLARE_DELAYED_WORK(fd_timer, fd_timer_workfn);
 
 static void cancel_activity(void)
 {
@@ -982,7 +996,7 @@ static void cancel_activity(void)
 
 /* this function makes sure that the disk stays in the drive during the
  * transfer */
-static void fd_watchdog(struct work_struct *arg)
+static void fd_watchdog(void)
 {
         debug_dcl(DP->flags, "calling disk change from watchdog\n");
 
@@ -993,7 +1007,7 @@ static void fd_watchdog(struct work_struct *arg)
                 reset_fdc();
         } else {
                 cancel_delayed_work(&fd_timer);
-                PREPARE_DELAYED_WORK(&fd_timer, fd_watchdog);
+                fd_timer_fn = fd_watchdog;
                 queue_delayed_work(floppy_wq, &fd_timer, HZ / 10);
         }
 }
@@ -1005,7 +1019,8 @@ static void main_command_interrupt(void)
 }
 
 /* waits for a delay (spinup or select) to pass */
-static int fd_wait_for_completion(unsigned long expires, work_func_t function)
+static int fd_wait_for_completion(unsigned long expires,
+                                  void (*function)(void))
 {
         if (FDCS->reset) {
                 reset_fdc();    /* do the reset during sleep to win time
@@ -1016,7 +1031,7 @@ static int fd_wait_for_completion(unsigned long expires, work_func_t function)
 
         if (time_before(jiffies, expires)) {
                 cancel_delayed_work(&fd_timer);
-                PREPARE_DELAYED_WORK(&fd_timer, function);
+                fd_timer_fn = function;
                 queue_delayed_work(floppy_wq, &fd_timer, expires - jiffies);
                 return 1;
         }
@@ -1334,8 +1349,7 @@ static int fdc_dtr(void)
          * Pause 5 msec to avoid trouble. (Needs to be 2 jiffies)
          */
         FDCS->dtr = raw_cmd->rate & 3;
-        return fd_wait_for_completion(jiffies + 2UL * HZ / 100,
-                                      (work_func_t)floppy_ready);
+        return fd_wait_for_completion(jiffies + 2UL * HZ / 100, floppy_ready);
 }                               /* fdc_dtr */
 
 static void tell_sector(void)
@@ -1440,7 +1454,7 @@ static void setup_rw_floppy(void)
         int flags;
         int dflags;
         unsigned long ready_date;
-        work_func_t function;
+        void (*function)(void);
 
         flags = raw_cmd->flags;
         if (flags & (FD_RAW_READ | FD_RAW_WRITE))
@@ -1454,9 +1468,9 @@ static void setup_rw_floppy(void)
                  */
                 if (time_after(ready_date, jiffies + DP->select_delay)) {
                         ready_date -= DP->select_delay;
-                        function = (work_func_t)floppy_start;
+                        function = floppy_start;
                 } else
-                        function = (work_func_t)setup_rw_floppy;
+                        function = setup_rw_floppy;
 
                 /* wait until the floppy is spinning fast enough */
                 if (fd_wait_for_completion(ready_date, function))
@@ -1486,7 +1500,7 @@ static void setup_rw_floppy(void)
                 inr = result();
                 cont->interrupt();
         } else if (flags & FD_RAW_NEED_DISK)
-                fd_watchdog(NULL);
+                fd_watchdog();
 }
 
 static int blind_seek;
@@ -1863,7 +1877,7 @@ static int start_motor(void (*function)(void))
 
         /* wait_for_completion also schedules reset if needed. */
         return fd_wait_for_completion(DRS->select_date + DP->select_delay,
-                                      (work_func_t)function);
+                                      function);
 }
 
 static void floppy_ready(void)