BMC/Intel-BMC/linux.git/block/blk-cgroup.c, branch dev-5.4

blkcg: make blkcg_print_stat() print stats only for online blkgs

2019-11-07T00:08:38+00:00

blkcg_print_stat() iterates blkgs under RCU and doesn't test whether the blkg is online. This can call into pd_stat_fn() on a pd which is still being initialized leading to an oops. The heaviest operation - recursively summing up rwstat counters - is already done while holding the queue_lock. Expand queue_lock to cover the other operations and skip the blkg if it isn't online yet. The online state is protected by both blkcg and queue locks, so this guarantees that only online blkgs are processed. Signed-off-by: Tejun Heo Reported-by: Roman Gushchin Cc: Josef Bacik Fixes: 903d23f0a354 ("blk-cgroup: allow controllers to output their own stats") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Jens Axboe

blkcg: Fix multiple bugs in blkcg_activate_policy()

2019-10-15T16:13:00+00:00

blkcg_activate_policy() has the following bugs. * cf09a8ee19ad ("blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn()") added @blkcg to ->pd_alloc_fn(); however, blkcg_activate_policy() ends up using pd's allocated for the root blkcg for all preallocations, so ->pd_init_fn() for non-root blkcgs can be passed in pd's which are allocated for the root blkcg. For blk-iocost, this means that ->pd_init_fn() can write beyond the end of the allocated object as it determines the length of the flex array at the end based on the blkcg's nesting level. * Each pd is initialized as they get allocated. If alloc fails, the policy will get freed with pd's initialized on it. * After the above partial failure, the partial pds are not freed. This patch fixes all the above issues by * Restructuring blkcg_activate_policy() so that alloc and init passes are separate. Init takes place only after all allocs succeeded and on failure all allocated pds are freed. * Unifying and fixing the cleanup of the remaining pd_prealloc. Signed-off-by: Tejun Heo Fixes: cf09a8ee19ad ("blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn()") Signed-off-by: Jens Axboe

bfq: Fix bfq linkage error

2019-09-14T17:33:43+00:00

Since commit 795fe54c2a828099e ("bfq: Add per-device weight"), bfq uses blkg_conf_prep() and blkg_conf_finish(), which are not exported. So, it causes linkage error if bfq compiled as a module. Fixes: 795fe54c2a828099e ("bfq: Add per-device weight") Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe

blkcg: separate blkcg_conf_get_disk() out of blkg_conf_prep()

2019-08-29T03:17:04+00:00

Separate out blkcg_conf_get_disk() so that it can be used by blkcg policy interface file input parsers before the policy is actually enabled. This doesn't introduce any functional changes. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

blkcg: make ->cpd_init_fn() optional

2019-08-29T03:17:03+00:00

For policies which can do enough initialization from ->cpd_alloc_fn(), make ->cpd_init_fn() optional. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn()

2019-08-29T03:17:01+00:00

Instead of @node, pass in @q and @blkcg so that the alloc function has more context. This doesn't cause any behavior change and will be used by io.weight implementation. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

blkcg: allow blkcg_policy->pd_stat() to print non-debug info too

2019-07-16T16:06:39+00:00

Currently, ->pd_stat() is called only when moduleparam blkcg_debug_stats is set which prevents it from printing non-debug policy-specific statistics. Let's move debug testing down so that ->pd_stat() can print non-debug stat too. This patch doesn't cause any visible behavior change. Signed-off-by: Tejun Heo Cc: Josef Bacik Signed-off-by: Jens Axboe

blkcg: implement REQ_CGROUP_PUNT

2019-07-10T15:00:57+00:00

When a shared kthread needs to issue a bio for a cgroup, doing so synchronously can lead to priority inversions as the kthread can be trapped waiting for that cgroup. This patch implements REQ_CGROUP_PUNT flag which makes submit_bio() punt the actual issuing to a dedicated per-blkcg work item to avoid such priority inversions. This will be used to fix priority inversions in btrfs compression and should be generally useful as we grow filesystem support for comprehensive IO control. Cc: Chris Mason Reviewed-by: Josef Bacik Reviewed-by: Jan Kara Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

cgroup, blkcg: Prepare some symbols for module and !CONFIG_CGROUP usages

2019-07-10T15:00:57+00:00

btrfs is going to use css_put() and wbc helpers to improve cgroup writeback support. Add dummy css_get() definition and export wbc helpers to prepare for module and !CONFIG_CGROUP builds. Reported-by: kbuild test robot Reviewed-by: Jan Kara Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

blk-cgroup: turn on psi memstall stuff

2019-07-10T15:00:57+00:00

With the psi stuff in place we can use the memstall flag to indicate pressure that happens from throttling. Signed-off-by: Josef Bacik Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe