4.4-stable review patch. If anyone has any objections, please let me know.
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From: Leonard Crestez leonard.crestez@nxp.com
commit d80771c08363ad7fbf0f56f5301e7ca65065c582 upstream.
When compiling with CONFIG_DEBUG_ATOMIC_SLEEP=y the mxs-dcp driver prints warnings such as:
WARNING: CPU: 0 PID: 120 at kernel/sched/core.c:7736 __might_sleep+0x98/0x9c do not call blocking ops when !TASK_RUNNING; state=1 set at [<8081978c>] dcp_chan_thread_sha+0x3c/0x2ec
The problem is that blocking ops will manipulate current->state themselves so it is not allowed to call them between set_current_state(TASK_INTERRUPTIBLE) and schedule().
Fix this by converting the per-chan mutex to a spinlock (it only protects tiny list ops anyway) and rearranging the wait logic so that callbacks are called current->state as TASK_RUNNING. Those callbacks will indeed call blocking ops themselves so this is required.
Cc: stable@vger.kernel.org Signed-off-by: Leonard Crestez leonard.crestez@nxp.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/crypto/mxs-dcp.c | 53 ++++++++++++++++++++++++++--------------------- 1 file changed, 30 insertions(+), 23 deletions(-)
--- a/drivers/crypto/mxs-dcp.c +++ b/drivers/crypto/mxs-dcp.c @@ -63,7 +63,7 @@ struct dcp { struct dcp_coherent_block *coh;
struct completion completion[DCP_MAX_CHANS]; - struct mutex mutex[DCP_MAX_CHANS]; + spinlock_t lock[DCP_MAX_CHANS]; struct task_struct *thread[DCP_MAX_CHANS]; struct crypto_queue queue[DCP_MAX_CHANS]; }; @@ -349,13 +349,20 @@ static int dcp_chan_thread_aes(void *dat
int ret;
- do { - __set_current_state(TASK_INTERRUPTIBLE); + while (!kthread_should_stop()) { + set_current_state(TASK_INTERRUPTIBLE);
- mutex_lock(&sdcp->mutex[chan]); + spin_lock(&sdcp->lock[chan]); backlog = crypto_get_backlog(&sdcp->queue[chan]); arq = crypto_dequeue_request(&sdcp->queue[chan]); - mutex_unlock(&sdcp->mutex[chan]); + spin_unlock(&sdcp->lock[chan]); + + if (!backlog && !arq) { + schedule(); + continue; + } + + set_current_state(TASK_RUNNING);
if (backlog) backlog->complete(backlog, -EINPROGRESS); @@ -363,11 +370,8 @@ static int dcp_chan_thread_aes(void *dat if (arq) { ret = mxs_dcp_aes_block_crypt(arq); arq->complete(arq, ret); - continue; } - - schedule(); - } while (!kthread_should_stop()); + }
return 0; } @@ -407,9 +411,9 @@ static int mxs_dcp_aes_enqueue(struct ab rctx->ecb = ecb; actx->chan = DCP_CHAN_CRYPTO;
- mutex_lock(&sdcp->mutex[actx->chan]); + spin_lock(&sdcp->lock[actx->chan]); ret = crypto_enqueue_request(&sdcp->queue[actx->chan], &req->base); - mutex_unlock(&sdcp->mutex[actx->chan]); + spin_unlock(&sdcp->lock[actx->chan]);
wake_up_process(sdcp->thread[actx->chan]);
@@ -645,13 +649,20 @@ static int dcp_chan_thread_sha(void *dat struct ahash_request *req; int ret, fini;
- do { - __set_current_state(TASK_INTERRUPTIBLE); + while (!kthread_should_stop()) { + set_current_state(TASK_INTERRUPTIBLE);
- mutex_lock(&sdcp->mutex[chan]); + spin_lock(&sdcp->lock[chan]); backlog = crypto_get_backlog(&sdcp->queue[chan]); arq = crypto_dequeue_request(&sdcp->queue[chan]); - mutex_unlock(&sdcp->mutex[chan]); + spin_unlock(&sdcp->lock[chan]); + + if (!backlog && !arq) { + schedule(); + continue; + } + + set_current_state(TASK_RUNNING);
if (backlog) backlog->complete(backlog, -EINPROGRESS); @@ -663,12 +674,8 @@ static int dcp_chan_thread_sha(void *dat ret = dcp_sha_req_to_buf(arq); fini = rctx->fini; arq->complete(arq, ret); - if (!fini) - continue; } - - schedule(); - } while (!kthread_should_stop()); + }
return 0; } @@ -726,9 +733,9 @@ static int dcp_sha_update_fx(struct ahas rctx->init = 1; }
- mutex_lock(&sdcp->mutex[actx->chan]); + spin_lock(&sdcp->lock[actx->chan]); ret = crypto_enqueue_request(&sdcp->queue[actx->chan], &req->base); - mutex_unlock(&sdcp->mutex[actx->chan]); + spin_unlock(&sdcp->lock[actx->chan]);
wake_up_process(sdcp->thread[actx->chan]); mutex_unlock(&actx->mutex); @@ -984,7 +991,7 @@ static int mxs_dcp_probe(struct platform platform_set_drvdata(pdev, sdcp);
for (i = 0; i < DCP_MAX_CHANS; i++) { - mutex_init(&sdcp->mutex[i]); + spin_lock_init(&sdcp->lock[i]); init_completion(&sdcp->completion[i]); crypto_init_queue(&sdcp->queue[i], 50); }