linux-kernel - [PATCH 24/23] floppy: cleanup: do not iterate on current_fdc in do_floppy

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Date:   Fri, 10 Apr 2020 11:30:23 +0200
From:   Willy Tarreau <w@....eu>
To:     Denis Efremov <efremov@...ux.com>
Cc:     Jens Axboe <axboe@...nel.dk>, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, Willy Tarreau <w@....eu>
Subject: [PATCH 24/23] floppy: cleanup: do not iterate on current_fdc in do_floppy_init()

There's no need to iterate on current_fdc in do_floppy_init() anymore,
in the first case it's only used as an array index to access fdc_state[],
so let's get rid of this confusing assignment. The second case is a bit
trickier because user_reset_fdc() needs to already know current_fdc when
called with drive==-1 due to this call chain:

    user_reset_fdc()
      lock_fdc()
        set_fdc()
           drive<0 ==> new_fdc = current_fdc

Note that current_drive is not used in this code part and may even not
match a unit belonging to current_fdc. Instead of passing -1 we can
simply pass the first drive of the FDC being initialized, which is even
cleaner as it will allow the function chain above to consistently assign
both variables.

Signed-off-by: Willy Tarreau <w@....eu>
---
 drivers/block/floppy.c | 38 ++++++++++++++++++--------------------
 1 file changed, 18 insertions(+), 20 deletions(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 07218f8b17f9..8da7921659f1 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4657,16 +4657,15 @@ static int __init do_floppy_init(void)
 	config_types();
 
 	for (i = 0; i < N_FDC; i++) {
-		current_fdc = i;
-		memset(&fdc_state[current_fdc], 0, sizeof(*fdc_state));
-		fdc_state[current_fdc].dtr = -1;
-		fdc_state[current_fdc].dor = 0x4;
+		memset(&fdc_state[i], 0, sizeof(*fdc_state));
+		fdc_state[i].dtr = -1;
+		fdc_state[i].dor = 0x4;
 #if defined(__sparc__) || defined(__mc68000__)
 	/*sparcs/sun3x don't have a DOR reset which we can fall back on to */
 #ifdef __mc68000__
 		if (MACH_IS_SUN3X)
 #endif
-			fdc_state[current_fdc].version = FDC_82072A;
+			fdc_state[i].version = FDC_82072A;
 #endif
 	}
 
@@ -4708,30 +4707,29 @@ static int __init do_floppy_init(void)
 	msleep(10);
 
 	for (i = 0; i < N_FDC; i++) {
-		current_fdc = i;
-		fdc_state[current_fdc].driver_version = FD_DRIVER_VERSION;
+		fdc_state[i].driver_version = FD_DRIVER_VERSION;
 		for (unit = 0; unit < 4; unit++)
-			fdc_state[current_fdc].track[unit] = 0;
-		if (fdc_state[current_fdc].address == -1)
+			fdc_state[i].track[unit] = 0;
+		if (fdc_state[i].address == -1)
 			continue;
-		fdc_state[current_fdc].rawcmd = 2;
-		if (user_reset_fdc(-1, FD_RESET_ALWAYS, false)) {
+		fdc_state[i].rawcmd = 2;
+		if (user_reset_fdc(REVDRIVE(i, 0), FD_RESET_ALWAYS, false)) {
 			/* free ioports reserved by floppy_grab_irq_and_dma() */
-			floppy_release_regions(current_fdc);
-			fdc_state[current_fdc].address = -1;
-			fdc_state[current_fdc].version = FDC_NONE;
+			floppy_release_regions(i);
+			fdc_state[i].address = -1;
+			fdc_state[i].version = FDC_NONE;
 			continue;
 		}
 		/* Try to determine the floppy controller type */
-		fdc_state[current_fdc].version = get_fdc_version(current_fdc);
-		if (fdc_state[current_fdc].version == FDC_NONE) {
+		fdc_state[i].version = get_fdc_version(i);
+		if (fdc_state[i].version == FDC_NONE) {
 			/* free ioports reserved by floppy_grab_irq_and_dma() */
-			floppy_release_regions(current_fdc);
-			fdc_state[current_fdc].address = -1;
+			floppy_release_regions(i);
+			fdc_state[i].address = -1;
 			continue;
 		}
 		if (can_use_virtual_dma == 2 &&
-		    fdc_state[current_fdc].version < FDC_82072A)
+		    fdc_state[i].version < FDC_82072A)
 			can_use_virtual_dma = 0;
 
 		have_no_fdc = 0;
@@ -4739,7 +4737,7 @@ static int __init do_floppy_init(void)
 		 * properly, so force a reset for the standard FDC clones,
 		 * to avoid interrupt garbage.
 		 */
-		user_reset_fdc(-1, FD_RESET_ALWAYS, false);
+		user_reset_fdc(REVDRIVE(i, 0), FD_RESET_ALWAYS, false);
 	}
 	current_fdc = 0;
 	cancel_delayed_work(&fd_timeout);
-- 
2.20.1