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dmaengine: idxd: fix missed completion on abort path
Ming reported that with the abort path of the descriptor submission, there
can be a window where a completed descriptor can be missed to be completed
by the irq completion thread:
CPU A CPU B
Submit (successful)
Submit (fail)
irq_process_work_list() // empty
llist_abort_desc()
// remove all descs from pending list
irq_process_pending_llist() // empty
exit idxd_wq_thread() with no processing
Add opportunistic descriptor completion in the abort path in order to
remove the missed completion.
Fixes: 6b4b87f2c3
("dmaengine: idxd: fix submission race window")
Reported-by: Ming Li <ming4.li@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163898288714.443911.16084982766671976640.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
parent
80936d6866
commit
8affd8a4b5
1 changed files with 17 additions and 1 deletions
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@ -106,6 +106,7 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
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{
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struct idxd_desc *d, *t, *found = NULL;
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struct llist_node *head;
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LIST_HEAD(flist);
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desc->completion->status = IDXD_COMP_DESC_ABORT;
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/*
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@ -120,7 +121,11 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
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found = desc;
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continue;
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}
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list_add_tail(&desc->list, &ie->work_list);
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if (d->completion->status)
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list_add_tail(&d->list, &flist);
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else
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list_add_tail(&d->list, &ie->work_list);
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}
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}
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@ -130,6 +135,17 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
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if (found)
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complete_desc(found, IDXD_COMPLETE_ABORT);
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/*
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* complete_desc() will return desc to allocator and the desc can be
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* acquired by a different process and the desc->list can be modified.
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* Delete desc from list so the list trasversing does not get corrupted
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* by the other process.
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*/
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list_for_each_entry_safe(d, t, &flist, list) {
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list_del_init(&d->list);
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complete_desc(d, IDXD_COMPLETE_NORMAL);
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}
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}
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int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
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