[PATCH 27/23] floppy: cleanup: make set_fdc() always set current_drive and current_fd

Willy Tarreau
2020-04-10T10:19:22Z

When called with a negative drive value, set_fdc() would stick to the
current fdc (which was assumed to reflect the current_drive's FDC). We
do not need this anymore as the last call place with a negative value
was just addressed. Let's make this function always set both current_fdc
and current_drive so that there's no more ambiguity. A few comments
stating this were added to a few non-obvious places.

Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/block/floppy.c | 43 ++++++++++++++++++++++++++++--------------
1 file changed, 29 insertions(+), 14 deletions(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 20646d4c5437..2817170dd403 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -851,31 +851,42 @@ static void reset_fdc_info(int fdc, int mode)
drive_state[drive].track = NEED_2_RECAL;
}

-/* selects the fdc and drive, and enables the fdc's input/dma. */
+/*
+ * selects the fdc and drive, and enables the fdc's input/dma.
+ * Both current_drive and current_fdc are changed to match the new drive.
+ */
static void set_fdc(int drive)
{
- unsigned int new_fdc = current_fdc;
+ unsigned int fdc;

- if (drive >= 0 && drive < N_DRIVE) {
- new_fdc = FDC(drive);
- current_drive = drive;
+ if (drive < 0 || drive >= N_DRIVE) {
+ pr_info("bad drive value %d\n", drive);
+ return;
}
- if (new_fdc >= N_FDC) {
+
+ fdc = FDC(drive);
+ if (fdc >= N_FDC) {
pr_info("bad fdc value\n");
return;
}
- current_fdc = new_fdc;
- set_dor(current_fdc, ~0, 8);
+
+ set_dor(fdc, ~0, 8);
#if N_FDC > 1
- set_dor(1 - current_fdc, ~8, 0);
+ set_dor(1 - fdc, ~8, 0);
#endif
- if (fdc_state[current_fdc].rawcmd == 2)
- reset_fdc_info(current_fdc, 1);
- if (fdc_inb(current_fdc, FD_STATUS) != STATUS_READY)
- fdc_state[current_fdc].reset = 1;
+ if (fdc_state[fdc].rawcmd == 2)
+ reset_fdc_info(fdc, 1);
+ if (fdc_inb(fdc, FD_STATUS) != STATUS_READY)
+ fdc_state[fdc].reset = 1;
+
+ current_drive = drive;
+ current_fdc = fdc;
}

-/* locks the driver */
+/*
+ * locks the driver.
+ * Both current_drive and current_fdc are changed to match the new drive.
+ */
static int lock_fdc(int drive)
{
if (WARN(atomic_read(&usage_count) == 0,
@@ -3000,6 +3011,10 @@ static const struct cont_t reset_cont = {
.done = generic_done
};

+/*
+ * Resets the FDC connected to drive <drive>.
+ * Both current_drive and current_fdc are changed to match the new drive.
+ */
static int user_reset_fdc(int drive, int arg, bool interruptible)
{
int ret;
--
2.20.1