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Tejun Heo 852c788f83 block: implement bio_associate_current() ... IO scheduling and cgroup are tied to the issuing task via io_context and cgroup of %current. Unfortunately, there are cases where IOs need to be routed via a different task which makes scheduling and cgroup limit enforcement applied completely incorrectly. For example, all bios delayed by blk-throttle end up being issued by a delayed work item and get assigned the io_context of the worker task which happens to serve the work item and dumped to the default block cgroup. This is double confusing as bios which aren't delayed end up in the correct cgroup and makes using blk-throttle and cfq propio together impossible. Any code which punts IO issuing to another task is affected which is getting more and more common (e.g. btrfs). As both io_context and cgroup are firmly tied to task including userland visible APIs to manipulate them, it makes a lot of sense to match up tasks to bios. This patch implements bio_associate_current() which associates the specified bio with %current. The bio will record the associated ioc and blkcg at that point and block layer will use the recorded ones regardless of which task actually ends up issuing the bio. bio release puts the associated ioc and blkcg. It grabs and remembers ioc and blkcg instead of the task itself because task may already be dead by the time the bio is issued making ioc and blkcg inaccessible and those are all block layer cares about. elevator_set_req_fn() is updated such that the bio elvdata is being allocated for is available to the elevator. This doesn't update block cgroup policies yet. Further patches will implement the support. -v2: #ifdef CONFIG_BLK_CGROUP added around bio->bi_ioc dereference in rq_ioc() to fix build breakage. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Kent Overstreet <koverstreet@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>		13 years ago
..
partitions	…
Kconfig	…
Kconfig.iosched	blkcg: make CONFIG_BLK_CGROUP bool	13 years ago
Makefile	…
blk-cgroup.c	blkcg: drop unnecessary RCU locking	13 years ago
blk-cgroup.h	blkcg: drop unnecessary RCU locking	13 years ago
blk-core.c	block: implement bio_associate_current()	13 years ago
blk-exec.c	…
blk-flush.c	…
blk-integrity.c	…
blk-ioc.c	block: add io_context->active_ref	13 years ago
blk-iopoll.c	…
blk-lib.c	…
blk-map.c	…
blk-merge.c	…
blk-settings.c	…
blk-softirq.c	…
blk-sysfs.c	blkcg: unify blkg's for blkcg policies	13 years ago
blk-tag.c	…
blk-throttle.c	blkcg: drop unnecessary RCU locking	13 years ago
blk-timeout.c	…
blk.h	block: interface update for ioc/icq creation functions	13 years ago
bsg-lib.c	…
bsg.c	…
cfq-iosched.c	block: implement bio_associate_current()	13 years ago
cfq.h	blkcg: use double locking instead of RCU for blkg synchronization	13 years ago
compat_ioctl.c	…
deadline-iosched.c	elevator: make elevator_init_fn() return 0/-errno	13 years ago
elevator.c	block: implement bio_associate_current()	13 years ago
genhd.c	Block: use a freezable workqueue for disk-event polling	13 years ago
ioctl.c	…
noop-iosched.c	elevator: make elevator_init_fn() return 0/-errno	13 years ago
partition-generic.c	block: Fix NULL pointer dereference in sd_revalidate_disk	13 years ago
scsi_ioctl.c	…