Messages in this thread Patch in this message | | | Date | Thu, 5 Feb 2015 12:40:20 +0100 | From | Joerg Roedel <> | Subject | [PATCH v2] iommu/amd: Use wait_event in put_pasid_state_wait |
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On Wed, Feb 04, 2015 at 05:34:50PM +0100, Peter Zijlstra wrote: > You just lost your atomic_dec.
So this should be the correct version then.
From 2a52250e542d8964c8285a37b71fe838a44c05c4 Mon Sep 17 00:00:00 2001 From: Joerg Roedel <jroedel@suse.de> Date: Wed, 4 Feb 2015 15:50:38 +0100 Subject: [PATCH 1/2] iommu/amd: Use wait_event in put_pasid_state_wait
Now that I learned about possible spurious wakeups this place needs fixing too. Replace the self-coded sleep variant with the generic wait_event() helper.
Signed-off-by: Joerg Roedel <jroedel@suse.de> --- drivers/iommu/amd_iommu_v2.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index b6398d7..e01bc8f 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -266,14 +266,13 @@ static void put_pasid_state(struct pasid_state *pasid_state) static void put_pasid_state_wait(struct pasid_state *pasid_state) { - DEFINE_WAIT(wait); + /* Drop our reference */ + atomic_dec(&pasid_state->count); - prepare_to_wait(&pasid_state->wq, &wait, TASK_UNINTERRUPTIBLE); + /* Wait for others to drop their references */ + wait_event(pasid_state->wq, !atomic_read(&pasid_state->count)); - if (!atomic_dec_and_test(&pasid_state->count)) - schedule(); - - finish_wait(&pasid_state->wq, &wait); + /* Get rid of it */ free_pasid_state(pasid_state); } -- 1.8.4.5
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