diff options
author | Oded Gabbay <oded.gabbay@amd.com> | 2014-11-10 03:57:36 -0500 |
---|---|---|
committer | Oded Gabbay <oded.gabbay@amd.com> | 2014-11-10 03:57:36 -0500 |
commit | a015c1e92639cd65ebb49350abdf5ad15bce4448 (patch) | |
tree | 4a21405a0291301bfcc20068dbb86d043d7f5007 | |
parent | e7cc3dd48c7b0a4b2135a5a2145ad43a8192fa6a (diff) |
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>
-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) | |||
272 | 272 | ||
273 | static void put_pasid_state(struct pasid_state *pasid_state) | 273 | static void put_pasid_state(struct pasid_state *pasid_state) |
274 | { | 274 | { |
275 | if (atomic_dec_and_test(&pasid_state->count)) { | 275 | if (atomic_dec_and_test(&pasid_state->count)) |
276 | put_device_state(pasid_state->device_state); | ||
277 | wake_up(&pasid_state->wq); | 276 | wake_up(&pasid_state->wq); |
278 | } | ||
279 | } | 277 | } |
280 | 278 | ||
281 | static void put_pasid_state_wait(struct pasid_state *pasid_state) | 279 | 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) | |||
284 | 282 | ||
285 | prepare_to_wait(&pasid_state->wq, &wait, TASK_UNINTERRUPTIBLE); | 283 | prepare_to_wait(&pasid_state->wq, &wait, TASK_UNINTERRUPTIBLE); |
286 | 284 | ||
287 | if (atomic_dec_and_test(&pasid_state->count)) | 285 | if (!atomic_dec_and_test(&pasid_state->count)) |
288 | put_device_state(pasid_state->device_state); | ||
289 | else | ||
290 | schedule(); | 286 | schedule(); |
291 | 287 | ||
292 | finish_wait(&pasid_state->wq, &wait); | 288 | finish_wait(&pasid_state->wq, &wait); |