Revision 8700aff089843399f95bc7701ae87b642b35a716 authored by Edward Cree on 20 December 2019, 16:26:40 UTC, committed by David S. Miller on 21 December 2019, 05:56:48 UTC
It was possible for channel allocation logic to get confused between what it had and what it wanted, and end up trying to use the same channel for both PTP and regular TX. This led to a kernel panic: BUG: unable to handle page fault for address: 0000000000047635 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP PTI CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 5.4.0-rc3-ehc14+ #900 Hardware name: Dell Inc. PowerEdge R710/0M233H, BIOS 6.4.0 07/23/2013 RIP: 0010:native_queued_spin_lock_slowpath+0x188/0x1e0 Code: f3 90 48 8b 32 48 85 f6 74 f6 eb e8 c1 ee 12 83 e0 03 83 ee 01 48 c1 e0 05 48 63 f6 48 05 c0 98 02 00 48 03 04 f5 a0 c6 ed 81 <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 32 RSP: 0018:ffffc90000003d28 EFLAGS: 00010006 RAX: 0000000000047635 RBX: 0000000000000246 RCX: 0000000000040000 RDX: ffff888627a298c0 RSI: 0000000000003ffe RDI: ffff88861f6b8dd4 RBP: ffff8886225c6e00 R08: 0000000000040000 R09: 0000000000000000 R10: 0000000616f080c6 R11: 00000000000000c0 R12: ffff88861f6b8dd4 R13: ffffc90000003dc8 R14: ffff88861942bf00 R15: ffff8886150f2000 FS: 0000000000000000(0000) GS:ffff888627a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000047635 CR3: 000000000200a000 CR4: 00000000000006f0 Call Trace: <IRQ> _raw_spin_lock_irqsave+0x22/0x30 skb_queue_tail+0x1b/0x50 sock_queue_err_skb+0x9d/0xf0 __skb_complete_tx_timestamp+0x9d/0xc0 efx_dequeue_buffer+0x126/0x180 [sfc] efx_xmit_done+0x73/0x1c0 [sfc] efx_ef10_ev_process+0x56a/0xfe0 [sfc] ? tick_sched_do_timer+0x60/0x60 ? timerqueue_add+0x5d/0x70 ? enqueue_hrtimer+0x39/0x90 efx_poll+0x111/0x380 [sfc] ? rcu_accelerate_cbs+0x50/0x160 net_rx_action+0x14a/0x400 __do_softirq+0xdd/0x2d0 irq_exit+0xa0/0xb0 do_IRQ+0x53/0xe0 common_interrupt+0xf/0xf </IRQ> In the long run we intend to rewrite the channel allocation code, but for 'net' fix this by allocating extra_channels, and giving them TX queues, even if we do not in fact need them (e.g. on NICs without MAC TX timestamping), and thereby using simpler logic to assign the channels once they're allocated. Fixes: 3990a8fffbda ("sfc: allocate channels for XDP tx queues") Signed-off-by: Edward Cree <ecree@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 258a980
blk-mq-sched.c
// SPDX-License-Identifier: GPL-2.0
/*
* blk-mq scheduling framework
*
* Copyright (C) 2016 Jens Axboe
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/blk-mq.h>
#include <trace/events/block.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-debugfs.h"
#include "blk-mq-sched.h"
#include "blk-mq-tag.h"
#include "blk-wbt.h"
void blk_mq_sched_free_hctx_data(struct request_queue *q,
void (*exit)(struct blk_mq_hw_ctx *))
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i) {
if (exit && hctx->sched_data)
exit(hctx);
kfree(hctx->sched_data);
hctx->sched_data = NULL;
}
}
EXPORT_SYMBOL_GPL(blk_mq_sched_free_hctx_data);
void blk_mq_sched_assign_ioc(struct request *rq)
{
struct request_queue *q = rq->q;
struct io_context *ioc;
struct io_cq *icq;
/*
* May not have an IO context if it's a passthrough request
*/
ioc = current->io_context;
if (!ioc)
return;
spin_lock_irq(&q->queue_lock);
icq = ioc_lookup_icq(ioc, q);
spin_unlock_irq(&q->queue_lock);
if (!icq) {
icq = ioc_create_icq(ioc, q, GFP_ATOMIC);
if (!icq)
return;
}
get_io_context(icq->ioc);
rq->elv.icq = icq;
}
/*
* Mark a hardware queue as needing a restart. For shared queues, maintain
* a count of how many hardware queues are marked for restart.
*/
void blk_mq_sched_mark_restart_hctx(struct blk_mq_hw_ctx *hctx)
{
if (test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state))
return;
set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
}
EXPORT_SYMBOL_GPL(blk_mq_sched_mark_restart_hctx);
void blk_mq_sched_restart(struct blk_mq_hw_ctx *hctx)
{
if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state))
return;
clear_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
blk_mq_run_hw_queue(hctx, true);
}
/*
* Only SCSI implements .get_budget and .put_budget, and SCSI restarts
* its queue by itself in its completion handler, so we don't need to
* restart queue if .get_budget() returns BLK_STS_NO_RESOURCE.
*/
static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
{
struct request_queue *q = hctx->queue;
struct elevator_queue *e = q->elevator;
LIST_HEAD(rq_list);
do {
struct request *rq;
if (e->type->ops.has_work && !e->type->ops.has_work(hctx))
break;
if (!blk_mq_get_dispatch_budget(hctx))
break;
rq = e->type->ops.dispatch_request(hctx);
if (!rq) {
blk_mq_put_dispatch_budget(hctx);
break;
}
/*
* Now this rq owns the budget which has to be released
* if this rq won't be queued to driver via .queue_rq()
* in blk_mq_dispatch_rq_list().
*/
list_add(&rq->queuelist, &rq_list);
} while (blk_mq_dispatch_rq_list(q, &rq_list, true));
}
static struct blk_mq_ctx *blk_mq_next_ctx(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx)
{
unsigned short idx = ctx->index_hw[hctx->type];
if (++idx == hctx->nr_ctx)
idx = 0;
return hctx->ctxs[idx];
}
/*
* Only SCSI implements .get_budget and .put_budget, and SCSI restarts
* its queue by itself in its completion handler, so we don't need to
* restart queue if .get_budget() returns BLK_STS_NO_RESOURCE.
*/
static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
{
struct request_queue *q = hctx->queue;
LIST_HEAD(rq_list);
struct blk_mq_ctx *ctx = READ_ONCE(hctx->dispatch_from);
do {
struct request *rq;
if (!sbitmap_any_bit_set(&hctx->ctx_map))
break;
if (!blk_mq_get_dispatch_budget(hctx))
break;
rq = blk_mq_dequeue_from_ctx(hctx, ctx);
if (!rq) {
blk_mq_put_dispatch_budget(hctx);
break;
}
/*
* Now this rq owns the budget which has to be released
* if this rq won't be queued to driver via .queue_rq()
* in blk_mq_dispatch_rq_list().
*/
list_add(&rq->queuelist, &rq_list);
/* round robin for fair dispatch */
ctx = blk_mq_next_ctx(hctx, rq->mq_ctx);
} while (blk_mq_dispatch_rq_list(q, &rq_list, true));
WRITE_ONCE(hctx->dispatch_from, ctx);
}
void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
{
struct request_queue *q = hctx->queue;
struct elevator_queue *e = q->elevator;
const bool has_sched_dispatch = e && e->type->ops.dispatch_request;
LIST_HEAD(rq_list);
/* RCU or SRCU read lock is needed before checking quiesced flag */
if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)))
return;
hctx->run++;
/*
* If we have previous entries on our dispatch list, grab them first for
* more fair dispatch.
*/
if (!list_empty_careful(&hctx->dispatch)) {
spin_lock(&hctx->lock);
if (!list_empty(&hctx->dispatch))
list_splice_init(&hctx->dispatch, &rq_list);
spin_unlock(&hctx->lock);
}
/*
* Only ask the scheduler for requests, if we didn't have residual
* requests from the dispatch list. This is to avoid the case where
* we only ever dispatch a fraction of the requests available because
* of low device queue depth. Once we pull requests out of the IO
* scheduler, we can no longer merge or sort them. So it's best to
* leave them there for as long as we can. Mark the hw queue as
* needing a restart in that case.
*
* We want to dispatch from the scheduler if there was nothing
* on the dispatch list or we were able to dispatch from the
* dispatch list.
*/
if (!list_empty(&rq_list)) {
blk_mq_sched_mark_restart_hctx(hctx);
if (blk_mq_dispatch_rq_list(q, &rq_list, false)) {
if (has_sched_dispatch)
blk_mq_do_dispatch_sched(hctx);
else
blk_mq_do_dispatch_ctx(hctx);
}
} else if (has_sched_dispatch) {
blk_mq_do_dispatch_sched(hctx);
} else if (hctx->dispatch_busy) {
/* dequeue request one by one from sw queue if queue is busy */
blk_mq_do_dispatch_ctx(hctx);
} else {
blk_mq_flush_busy_ctxs(hctx, &rq_list);
blk_mq_dispatch_rq_list(q, &rq_list, false);
}
}
bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
unsigned int nr_segs, struct request **merged_request)
{
struct request *rq;
switch (elv_merge(q, &rq, bio)) {
case ELEVATOR_BACK_MERGE:
if (!blk_mq_sched_allow_merge(q, rq, bio))
return false;
if (!bio_attempt_back_merge(rq, bio, nr_segs))
return false;
*merged_request = attempt_back_merge(q, rq);
if (!*merged_request)
elv_merged_request(q, rq, ELEVATOR_BACK_MERGE);
return true;
case ELEVATOR_FRONT_MERGE:
if (!blk_mq_sched_allow_merge(q, rq, bio))
return false;
if (!bio_attempt_front_merge(rq, bio, nr_segs))
return false;
*merged_request = attempt_front_merge(q, rq);
if (!*merged_request)
elv_merged_request(q, rq, ELEVATOR_FRONT_MERGE);
return true;
case ELEVATOR_DISCARD_MERGE:
return bio_attempt_discard_merge(q, rq, bio);
default:
return false;
}
}
EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
/*
* Iterate list of requests and see if we can merge this bio with any
* of them.
*/
bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list,
struct bio *bio, unsigned int nr_segs)
{
struct request *rq;
int checked = 8;
list_for_each_entry_reverse(rq, list, queuelist) {
bool merged = false;
if (!checked--)
break;
if (!blk_rq_merge_ok(rq, bio))
continue;
switch (blk_try_merge(rq, bio)) {
case ELEVATOR_BACK_MERGE:
if (blk_mq_sched_allow_merge(q, rq, bio))
merged = bio_attempt_back_merge(rq, bio,
nr_segs);
break;
case ELEVATOR_FRONT_MERGE:
if (blk_mq_sched_allow_merge(q, rq, bio))
merged = bio_attempt_front_merge(rq, bio,
nr_segs);
break;
case ELEVATOR_DISCARD_MERGE:
merged = bio_attempt_discard_merge(q, rq, bio);
break;
default:
continue;
}
return merged;
}
return false;
}
EXPORT_SYMBOL_GPL(blk_mq_bio_list_merge);
/*
* Reverse check our software queue for entries that we could potentially
* merge with. Currently includes a hand-wavy stop count of 8, to not spend
* too much time checking for merges.
*/
static bool blk_mq_attempt_merge(struct request_queue *q,
struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx, struct bio *bio,
unsigned int nr_segs)
{
enum hctx_type type = hctx->type;
lockdep_assert_held(&ctx->lock);
if (blk_mq_bio_list_merge(q, &ctx->rq_lists[type], bio, nr_segs)) {
ctx->rq_merged++;
return true;
}
return false;
}
bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
unsigned int nr_segs)
{
struct elevator_queue *e = q->elevator;
struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, bio->bi_opf, ctx);
bool ret = false;
enum hctx_type type;
if (e && e->type->ops.bio_merge)
return e->type->ops.bio_merge(hctx, bio, nr_segs);
type = hctx->type;
if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
!list_empty_careful(&ctx->rq_lists[type])) {
/* default per sw-queue merge */
spin_lock(&ctx->lock);
ret = blk_mq_attempt_merge(q, hctx, ctx, bio, nr_segs);
spin_unlock(&ctx->lock);
}
return ret;
}
bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq)
{
return rq_mergeable(rq) && elv_attempt_insert_merge(q, rq);
}
EXPORT_SYMBOL_GPL(blk_mq_sched_try_insert_merge);
void blk_mq_sched_request_inserted(struct request *rq)
{
trace_block_rq_insert(rq->q, rq);
}
EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted);
static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx,
bool has_sched,
struct request *rq)
{
/* dispatch flush rq directly */
if (rq->rq_flags & RQF_FLUSH_SEQ) {
spin_lock(&hctx->lock);
list_add(&rq->queuelist, &hctx->dispatch);
spin_unlock(&hctx->lock);
return true;
}
if (has_sched)
rq->rq_flags |= RQF_SORTED;
return false;
}
void blk_mq_sched_insert_request(struct request *rq, bool at_head,
bool run_queue, bool async)
{
struct request_queue *q = rq->q;
struct elevator_queue *e = q->elevator;
struct blk_mq_ctx *ctx = rq->mq_ctx;
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
/* flush rq in flush machinery need to be dispatched directly */
if (!(rq->rq_flags & RQF_FLUSH_SEQ) && op_is_flush(rq->cmd_flags)) {
blk_insert_flush(rq);
goto run;
}
WARN_ON(e && (rq->tag != -1));
if (blk_mq_sched_bypass_insert(hctx, !!e, rq))
goto run;
if (e && e->type->ops.insert_requests) {
LIST_HEAD(list);
list_add(&rq->queuelist, &list);
e->type->ops.insert_requests(hctx, &list, at_head);
} else {
spin_lock(&ctx->lock);
__blk_mq_insert_request(hctx, rq, at_head);
spin_unlock(&ctx->lock);
}
run:
if (run_queue)
blk_mq_run_hw_queue(hctx, async);
}
void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx,
struct list_head *list, bool run_queue_async)
{
struct elevator_queue *e;
struct request_queue *q = hctx->queue;
/*
* blk_mq_sched_insert_requests() is called from flush plug
* context only, and hold one usage counter to prevent queue
* from being released.
*/
percpu_ref_get(&q->q_usage_counter);
e = hctx->queue->elevator;
if (e && e->type->ops.insert_requests)
e->type->ops.insert_requests(hctx, list, false);
else {
/*
* try to issue requests directly if the hw queue isn't
* busy in case of 'none' scheduler, and this way may save
* us one extra enqueue & dequeue to sw queue.
*/
if (!hctx->dispatch_busy && !e && !run_queue_async) {
blk_mq_try_issue_list_directly(hctx, list);
if (list_empty(list))
goto out;
}
blk_mq_insert_requests(hctx, ctx, list);
}
blk_mq_run_hw_queue(hctx, run_queue_async);
out:
percpu_ref_put(&q->q_usage_counter);
}
static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set,
struct blk_mq_hw_ctx *hctx,
unsigned int hctx_idx)
{
if (hctx->sched_tags) {
blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx);
blk_mq_free_rq_map(hctx->sched_tags);
hctx->sched_tags = NULL;
}
}
static int blk_mq_sched_alloc_tags(struct request_queue *q,
struct blk_mq_hw_ctx *hctx,
unsigned int hctx_idx)
{
struct blk_mq_tag_set *set = q->tag_set;
int ret;
hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
set->reserved_tags);
if (!hctx->sched_tags)
return -ENOMEM;
ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests);
if (ret)
blk_mq_sched_free_tags(set, hctx, hctx_idx);
return ret;
}
/* called in queue's release handler, tagset has gone away */
static void blk_mq_sched_tags_teardown(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i) {
if (hctx->sched_tags) {
blk_mq_free_rq_map(hctx->sched_tags);
hctx->sched_tags = NULL;
}
}
}
int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
{
struct blk_mq_hw_ctx *hctx;
struct elevator_queue *eq;
unsigned int i;
int ret;
if (!e) {
q->elevator = NULL;
q->nr_requests = q->tag_set->queue_depth;
return 0;
}
/*
* Default to double of smaller one between hw queue_depth and 128,
* since we don't split into sync/async like the old code did.
* Additionally, this is a per-hw queue depth.
*/
q->nr_requests = 2 * min_t(unsigned int, q->tag_set->queue_depth,
BLKDEV_MAX_RQ);
queue_for_each_hw_ctx(q, hctx, i) {
ret = blk_mq_sched_alloc_tags(q, hctx, i);
if (ret)
goto err;
}
ret = e->ops.init_sched(q, e);
if (ret)
goto err;
blk_mq_debugfs_register_sched(q);
queue_for_each_hw_ctx(q, hctx, i) {
if (e->ops.init_hctx) {
ret = e->ops.init_hctx(hctx, i);
if (ret) {
eq = q->elevator;
blk_mq_sched_free_requests(q);
blk_mq_exit_sched(q, eq);
kobject_put(&eq->kobj);
return ret;
}
}
blk_mq_debugfs_register_sched_hctx(q, hctx);
}
return 0;
err:
blk_mq_sched_free_requests(q);
blk_mq_sched_tags_teardown(q);
q->elevator = NULL;
return ret;
}
/*
* called in either blk_queue_cleanup or elevator_switch, tagset
* is required for freeing requests
*/
void blk_mq_sched_free_requests(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
int i;
queue_for_each_hw_ctx(q, hctx, i) {
if (hctx->sched_tags)
blk_mq_free_rqs(q->tag_set, hctx->sched_tags, i);
}
}
void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e)
{
struct blk_mq_hw_ctx *hctx;
unsigned int i;
queue_for_each_hw_ctx(q, hctx, i) {
blk_mq_debugfs_unregister_sched_hctx(hctx);
if (e->type->ops.exit_hctx && hctx->sched_data) {
e->type->ops.exit_hctx(hctx, i);
hctx->sched_data = NULL;
}
}
blk_mq_debugfs_unregister_sched(q);
if (e->type->ops.exit_sched)
e->type->ops.exit_sched(e);
blk_mq_sched_tags_teardown(q);
q->elevator = NULL;
}
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