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| author | Oded Gabbay <oded.gabbay@amd.com> | 2014-11-10 11:57:36 +0300 |
|---|---|---|
| committer | Oded Gabbay <oded.gabbay@amd.com> | 2014-11-10 11:57:36 +0300 |
| commit | a015c1e92639cd65ebb49350abdf5ad15bce4448 (patch) | |
| tree | 4a21405a0291301bfcc20068dbb86d043d7f5007 /drivers/iommu/amd_iommu_v2.c | |
| parent | e7cc3dd48c7b0a4b2135a5a2145ad43a8192fa6a (diff) | |
| download | linux-a015c1e92639cd65ebb49350abdf5ad15bce4448.tar.xz | |
iommu/amd: fix accounting of device_state
This patch fixes a bug in the accounting of the device_state.
In the current code, the device_state was put (decremented) too many times,
which sometimes lead to the driver getting stuck permanently in
put_device_state_wait(). That happen because the device_state->count would go
below zero, which is never supposed to happen.
The root cause is that the device_state was decremented in put_pasid_state()
and put_pasid_state_wait() but also in all the functions that call those
functions. Therefore, the device_state was decremented twice in each of these
code paths.
The fix is to decouple the device_state accounting from the pasid_state
accounting - remove the call to put_device_state() from the
put_pasid_state() and the put_pasid_state_wait())
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>
Diffstat (limited to 'drivers/iommu/amd_iommu_v2.c')
| -rw-r--r-- | drivers/iommu/amd_iommu_v2.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index f724bdc50d25..1e6360e7ae44 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -272,10 +272,8 @@ static void free_pasid_state(struct pasid_state *pasid_state) static void put_pasid_state(struct pasid_state *pasid_state) { - if (atomic_dec_and_test(&pasid_state->count)) { - put_device_state(pasid_state->device_state); + if (atomic_dec_and_test(&pasid_state->count)) wake_up(&pasid_state->wq); - } } static void put_pasid_state_wait(struct pasid_state *pasid_state) @@ -284,9 +282,7 @@ static void put_pasid_state_wait(struct pasid_state *pasid_state) prepare_to_wait(&pasid_state->wq, &wait, TASK_UNINTERRUPTIBLE); - if (atomic_dec_and_test(&pasid_state->count)) - put_device_state(pasid_state->device_state); - else + if (!atomic_dec_and_test(&pasid_state->count)) schedule(); finish_wait(&pasid_state->wq, &wait); |