From 3aa72873ffdcc2f7919743efbbefc351ec73f5cb Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 21 Apr 2011 19:28:35 +0200 Subject: elevator: check for ELEVATOR_INSERT_SORT_MERGE in !elvpriv case too The sort insert is the one that goes to the IO scheduler. With the SORT_MERGE addition, we could bypass IO scheduler setup but still ask the IO scheduler to insert the request. This would cause an oops on switching IO schedulers through the sysfs interface, unless the disk just happened to be idle while it occured. Signed-off-by: Jens Axboe --- block/elevator.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/elevator.c b/block/elevator.c index 6f6abc08bb56..45ca1e34f582 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -671,7 +671,8 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where) q->boundary_rq = rq; } } else if (!(rq->cmd_flags & REQ_ELVPRIV) && - where == ELEVATOR_INSERT_SORT) + (where == ELEVATOR_INSERT_SORT || + where == ELEVATOR_INSERT_SORT_MERGE)) where = ELEVATOR_INSERT_BACK; switch (where) { -- cgit v1.2.3 From 7c88a168da8003fd4d8fb6ae103c4ecf29cb1130 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 21 Apr 2011 19:43:58 +0200 Subject: block: don't propagate unlisted DISK_EVENTs to userland DISK_EVENT_MEDIA_CHANGE is used for both userland visible event and internal event for revalidation of removeable devices. Some legacy drivers don't implement proper event detection and continuously generate events under certain circumstances. For example, ide-cd generates media changed continuously if there's no media in the drive, which can lead to infinite loop of events jumping back and forth between the driver and userland event handler. This patch updates disk event infrastructure such that it never propagates events not listed in disk->events to userland. Those events are processed the same for internal purposes but uevent generation is suppressed. This also ensures that userland only gets events which are advertised in the @events sysfs node lowering risk of confusion. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- block/genhd.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index b364bd038a18..2dd988723d73 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1588,9 +1588,13 @@ static void disk_events_workfn(struct work_struct *work) spin_unlock_irq(&ev->lock); - /* tell userland about new events */ + /* + * Tell userland about new events. Only the events listed in + * @disk->events are reported. Unlisted events are processed the + * same internally but never get reported to userland. + */ for (i = 0; i < ARRAY_SIZE(disk_uevents); i++) - if (events & (1 << i)) + if (events & disk->events & (1 << i)) envp[nr_events++] = disk_uevents[i]; if (nr_events) -- cgit v1.2.3 From 7eec77a1816a7042591a6cbdb4820e9e7ebffe0e Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 21 Apr 2011 19:43:59 +0200 Subject: ide: unexport DISK_EVENT_MEDIA_CHANGE for ide-gd and ide-cd check_events() implementations in both ide-gd and ide-cd are inadequate for in-kernel event polling. Both generate media change events continuously when certain conditions are met causing infinite event loop between the driver and userland event handler. As disk event now supports suppression of unlisted events, simply de-listing DISK_EVENT_MEDIA_CHANGE from disk->events resolves the problem. Internal handling around media revalidation will behave the same while userland will fall back to userland event polling after detecting the device doesn't support disk events. Signed-off-by: Tejun Heo Reported-by: Jens Axboe Acked-by: "David S. Miller" Signed-off-by: Jens Axboe --- drivers/ide/ide-cd.c | 1 - drivers/ide/ide-cd_ioctl.c | 6 ++++++ drivers/ide/ide-gd.c | 7 ++++++- 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c index fd1e11799137..a5ec5a7cb381 100644 --- a/drivers/ide/ide-cd.c +++ b/drivers/ide/ide-cd.c @@ -1782,7 +1782,6 @@ static int ide_cd_probe(ide_drive_t *drive) ide_cd_read_toc(drive, &sense); g->fops = &idecd_ops; g->flags |= GENHD_FL_REMOVABLE; - g->events = DISK_EVENT_MEDIA_CHANGE; add_disk(g); return 0; diff --git a/drivers/ide/ide-cd_ioctl.c b/drivers/ide/ide-cd_ioctl.c index 2a6bc50e8a41..02caa7dd51c8 100644 --- a/drivers/ide/ide-cd_ioctl.c +++ b/drivers/ide/ide-cd_ioctl.c @@ -79,6 +79,12 @@ int ide_cdrom_drive_status(struct cdrom_device_info *cdi, int slot_nr) return CDS_DRIVE_NOT_READY; } +/* + * ide-cd always generates media changed event if media is missing, which + * makes it impossible to use for proper event reporting, so disk->events + * is cleared to 0 and the following function is used only to trigger + * revalidation and never propagated to userland. + */ unsigned int ide_cdrom_check_events_real(struct cdrom_device_info *cdi, unsigned int clearing, int slot_nr) { diff --git a/drivers/ide/ide-gd.c b/drivers/ide/ide-gd.c index c4ffd4888939..70ea8763567d 100644 --- a/drivers/ide/ide-gd.c +++ b/drivers/ide/ide-gd.c @@ -298,6 +298,12 @@ static unsigned int ide_gd_check_events(struct gendisk *disk, return 0; } + /* + * The following is used to force revalidation on the first open on + * removeable devices, and never gets reported to userland as + * genhd->events is 0. This is intended as removeable ide disk + * can't really detect MEDIA_CHANGE events. + */ ret = drive->dev_flags & IDE_DFLAG_MEDIA_CHANGED; drive->dev_flags &= ~IDE_DFLAG_MEDIA_CHANGED; @@ -413,7 +419,6 @@ static int ide_gd_probe(ide_drive_t *drive) if (drive->dev_flags & IDE_DFLAG_REMOVABLE) g->flags = GENHD_FL_REMOVABLE; g->fops = &ide_gd_ops; - g->events = DISK_EVENT_MEDIA_CHANGE; add_disk(g); return 0; -- cgit v1.2.3