Revert "floppy: reintroduce O_NDELAY fix"

mainline inclusion
from mainline-5.10.62
commit 17982c664f8b2c9543241552331b008ad34d2648
bugzilla: 182217 https://gitee.com/openeuler/kernel/issues/I4EFOS

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=17982c664f8b2c9543241552331b008ad34d2648

--------------------------------

commit c7e9d002 upstream.

The patch breaks userspace implementations (e.g. fdutils) and introduces
regressions in behaviour. Previously, it was possible to O_NDELAY open a
floppy device with no media inserted or with write protected media without
an error. Some userspace tools use this particular behavior for probing.

It's not the first time when we revert this patch. Previous revert is in
commit f2791e7e (Revert "floppy: refactor open() flags handling").

This reverts commit 8a0c014c.

Link: https://lore.kernel.org/linux-block/de10cb47-34d1-5a88-7751-225ca380f735@compro.net/Reported-by: NMark Hounschell <markh@compro.net>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Wim Osterholt <wim@djo.tudelft.nl>
Cc: Kurt Garloff <kurt@garloff.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NDenis Efremov <efremov@linux.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/block/floppy.c

@@ -4120,23 +4120,23 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
 	if (fdc_state[FDC(drive)].rawcmd == 1)
 		fdc_state[FDC(drive)].rawcmd = 2;
 
-	if (mode & (FMODE_READ|FMODE_WRITE)) {
-		drive_state[drive].last_checked = 0;
-		clear_bit(FD_OPEN_SHOULD_FAIL_BIT, &drive_state[drive].flags);
-		if (bdev_check_media_change(bdev))
-			floppy_revalidate(bdev->bd_disk);
-		if (test_bit(FD_DISK_CHANGED_BIT, &drive_state[drive].flags))
-			goto out;
-		if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &drive_state[drive].flags))
+	if (!(mode & FMODE_NDELAY)) {
+		if (mode & (FMODE_READ|FMODE_WRITE)) {
+			drive_state[drive].last_checked = 0;
+			clear_bit(FD_OPEN_SHOULD_FAIL_BIT,
+				  &drive_state[drive].flags);
+			if (bdev_check_media_change(bdev))
+				floppy_revalidate(bdev->bd_disk);
+			if (test_bit(FD_DISK_CHANGED_BIT, &drive_state[drive].flags))
+				goto out;
+			if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &drive_state[drive].flags))
+				goto out;
+		}
+		res = -EROFS;
+		if ((mode & FMODE_WRITE) &&
+		    !test_bit(FD_DISK_WRITABLE_BIT, &drive_state[drive].flags))
 			goto out;
 	}
-
-	res = -EROFS;
-
-	if ((mode & FMODE_WRITE) &&
-			!test_bit(FD_DISK_WRITABLE_BIT, &drive_state[drive].flags))
-		goto out;
-
 	mutex_unlock(&open_lock);
 	mutex_unlock(&floppy_mutex);
 	return 0;