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That timestamp is also updated by disk_change() when another FDC operation observes that the disk-change line is clear. The worker path that calls disk_change() is not serialized by the floppy_mutex/open_lock pair held by floppy_open(). A worker can therefore store a recent jiffies value after floppy_open() stores zero and before the synchronous disk_check_media_change() call reaches floppy_check_events(). The checkfreq throttle can then treat the media-change state as fresh and skip the hardware poll that the open path explicitly tried to force. Use the block layer's clearing mask instead of a racy timestamp sentinel. When DISK_EVENT_MEDIA_CHANGE is being synchronously cleared, bypass the checkfreq throttle and poll the drive. Periodic event checks still use last_checked to avoid unnecessary polling, and floppy_open() no longer needs to write last_checked itself. Signed-off-by: Cen Zhang --- drivers/block/floppy.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 92e446a643712..7217db0b907b3 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -4051,7 +4051,6 @@ static int floppy_open(struct gendisk *disk, blk_mode_t mode) fdc_state[FDC(drive)].rawcmd = 2; if (!(mode & BLK_OPEN_NDELAY)) { if (mode & (BLK_OPEN_READ | BLK_OPEN_WRITE)) { - drive_state[drive].last_checked = 0; clear_bit(FD_OPEN_SHOULD_FAIL_BIT, &drive_state[drive].flags); if (disk_check_media_change(disk)) @@ -4092,7 +4091,9 @@ static unsigned int floppy_check_events(struct gendisk *disk, test_bit(FD_VERIFY_BIT, &drive_state[drive].flags)) return DISK_EVENT_MEDIA_CHANGE; - if (time_after(jiffies, drive_state[drive].last_checked + drive_params[drive].checkfreq)) { + if ((clearing & DISK_EVENT_MEDIA_CHANGE) || + time_after(jiffies, drive_state[drive].last_checked + + drive_params[drive].checkfreq)) { if (lock_fdc(drive)) return 0; poll_drive(false, 0); -- 2.43.0