[PATCH v8 3/8] crypto: caam - drop global context pointer and init_done

[Andrey Smirnov]

Leverage devres to get rid of code storing global context as well as
init_done flag.

Original code also has a circular deallocation dependency where
unregister_algs() -> caam_rng_exit() -> caam_jr_free() chain would
only happen if all of JRs were freed. Fix this by moving
caam_rng_exit() outside of unregister_algs() and doing it specifically
for JR that instantiated HWRNG.

Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
Cc: Chris Healy <cphealy@xxxxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Horia GeantÄ <horia.geanta@xxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: Iuliana Prodan <iuliana.prodan@xxxxxxx>
Cc: linux-crypto@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-imx@xxxxxxx
---
 drivers/crypto/caam/caamrng.c | 67 +++++++++++++++++------------------
 drivers/crypto/caam/intern.h  |  7 ++--
 drivers/crypto/caam/jr.c      | 13 ++++---
 3 files changed, 44 insertions(+), 43 deletions(-)

diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c
index 69a02ac5de54..753625f2b2c0 100644
--- a/drivers/crypto/caam/caamrng.c
+++ b/drivers/crypto/caam/caamrng.c
@@ -70,6 +70,7 @@ struct buf_data {
 
 /* rng per-device context */
 struct caam_rng_ctx {
+	struct hwrng rng;
 	struct device *jrdev;
 	dma_addr_t sh_desc_dma;
 	u32 sh_desc[DESC_RNG_LEN];
@@ -78,13 +79,10 @@ struct caam_rng_ctx {
 	struct buf_data bufs[2];
 };
 
-static struct caam_rng_ctx *rng_ctx;
-
-/*
- * Variable used to avoid double free of resources in case
- * algorithm registration was unsuccessful
- */
-static bool init_done;
+static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r)
+{
+	return (struct caam_rng_ctx *)r->priv;
+}
 
 static inline void rng_unmap_buf(struct device *jrdev, struct buf_data *bd)
 {
@@ -143,7 +141,7 @@ static inline int submit_job(struct caam_rng_ctx *ctx, int to_current)
 
 static int caam_read(struct hwrng *rng, void *data, size_t max, bool wait)
 {
-	struct caam_rng_ctx *ctx = rng_ctx;
+	struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
 	struct buf_data *bd = &ctx->bufs[ctx->current_buf];
 	int next_buf_idx, copied_idx;
 	int err;
@@ -246,17 +244,18 @@ static inline int rng_create_job_desc(struct caam_rng_ctx *ctx, int buf_id)
 
 static void caam_cleanup(struct hwrng *rng)
 {
+	struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
 	int i;
 	struct buf_data *bd;
 
 	for (i = 0; i < 2; i++) {
-		bd = &rng_ctx->bufs[i];
+		bd = &ctx->bufs[i];
 		if (atomic_read(&bd->empty) == BUF_PENDING)
 			wait_for_completion(&bd->filled);
 	}
 
-	rng_unmap_ctx(rng_ctx);
-	caam_jr_free(rng_ctx->jrdev);
+	rng_unmap_ctx(ctx);
+	caam_jr_free(ctx->jrdev);
 }
 
 static int caam_init_buf(struct caam_rng_ctx *ctx, int buf_id)
@@ -277,7 +276,7 @@ static int caam_init_buf(struct caam_rng_ctx *ctx, int buf_id)
 
 static int caam_init(struct hwrng *rng)
 {
-	struct caam_rng_ctx *ctx = rng_ctx;
+	struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
 	int err;
 
 	ctx->jrdev = caam_jr_alloc();
@@ -309,28 +308,19 @@ static int caam_init(struct hwrng *rng)
 	return err;
 }
 
-static struct hwrng caam_rng = {
-	.name		= "rng-caam",
-	.init           = caam_init,
-	.cleanup	= caam_cleanup,
-	.read		= caam_read,
-};
+int caam_rng_init(struct device *ctrldev);
 
-void caam_rng_exit(void)
+void caam_rng_exit(struct device *ctrldev)
 {
-	if (!init_done)
-		return;
-
-	hwrng_unregister(&caam_rng);
-	kfree(rng_ctx);
+	devres_release_group(ctrldev, caam_rng_init);
 }
 
 int caam_rng_init(struct device *ctrldev)
 {
+	struct caam_rng_ctx *ctx;
 	u32 rng_inst;
 	struct caam_drv_private *priv = dev_get_drvdata(ctrldev);
-	int err;
-	init_done = false;
+	int ret;
 
 	/* Check for an instantiated RNG before registration */
 	if (priv->era < 10)
@@ -342,18 +332,27 @@ int caam_rng_init(struct device *ctrldev)
 	if (!rng_inst)
 		return 0;
 
-	rng_ctx = kmalloc(sizeof(*rng_ctx), GFP_DMA | GFP_KERNEL);
-	if (!rng_ctx)
+	if (!devres_open_group(ctrldev, caam_rng_init, GFP_KERNEL))
+		return -ENOMEM;
+
+	ctx = devm_kzalloc(ctrldev, sizeof(*ctx), GFP_DMA | GFP_KERNEL);
+	if (!ctx)
 		return -ENOMEM;
 
+	ctx->rng.name    = "rng-caam";
+	ctx->rng.init    = caam_init;
+	ctx->rng.cleanup = caam_cleanup;
+	ctx->rng.read    = caam_read;
+	ctx->rng.priv    = (unsigned long)ctx;
+
 	dev_info(ctrldev, "registering rng-caam\n");
 
-	err = hwrng_register(&caam_rng);
-	if (!err) {
-		init_done = true;
-		return err;
+	ret = devm_hwrng_register(ctrldev, &ctx->rng);
+	if (ret) {
+		caam_rng_exit(ctrldev);
+		return ret;
 	}
 
-	kfree(rng_ctx);
-	return err;
+	devres_close_group(ctrldev, caam_rng_init);
+	return 0;
 }
diff --git a/drivers/crypto/caam/intern.h b/drivers/crypto/caam/intern.h
index 230ea88184f5..402d6a362e8c 100644
--- a/drivers/crypto/caam/intern.h
+++ b/drivers/crypto/caam/intern.h
@@ -47,6 +47,7 @@ struct caam_drv_private_jr {
 	struct caam_job_ring __iomem *rregs;	/* JobR's register space */
 	struct tasklet_struct irqtask;
 	int irq;			/* One per queue */
+	bool hwrng;
 
 	/* Number of scatterlist crypt transforms active on the JobR */
 	atomic_t tfm_count ____cacheline_aligned;
@@ -163,7 +164,7 @@ static inline void caam_pkc_exit(void)
 #ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_API
 
 int caam_rng_init(struct device *dev);
-void caam_rng_exit(void);
+void caam_rng_exit(struct device *dev);
 
 #else
 
@@ -172,9 +173,7 @@ static inline int caam_rng_init(struct device *dev)
 	return 0;
 }
 
-static inline void caam_rng_exit(void)
-{
-}
+static inline void caam_rng_exit(struct device *dev) {}
 
 #endif /* CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_API */
 
diff --git a/drivers/crypto/caam/jr.c b/drivers/crypto/caam/jr.c
index 88aff2aefd5d..4af22e7ceb4f 100644
--- a/drivers/crypto/caam/jr.c
+++ b/drivers/crypto/caam/jr.c
@@ -27,7 +27,8 @@ static struct jr_driver_data driver_data;
 static DEFINE_MUTEX(algs_lock);
 static unsigned int active_devs;
 
-static void register_algs(struct device *dev)
+static void register_algs(struct caam_drv_private_jr *jrpriv,
+			  struct device *dev)
 {
 	mutex_lock(&algs_lock);
 
@@ -37,7 +38,7 @@ static void register_algs(struct device *dev)
 	caam_algapi_init(dev);
 	caam_algapi_hash_init(dev);
 	caam_pkc_init(dev);
-	caam_rng_init(dev);
+	jrpriv->hwrng = !caam_rng_init(dev);
 	caam_qi_algapi_init(dev);
 
 algs_unlock:
@@ -53,7 +54,6 @@ static void unregister_algs(void)
 
 	caam_qi_algapi_exit();
 
-	caam_rng_exit();
 	caam_pkc_exit();
 	caam_algapi_hash_exit();
 	caam_algapi_exit();
@@ -135,6 +135,9 @@ static int caam_jr_remove(struct platform_device *pdev)
 	jrdev = &pdev->dev;
 	jrpriv = dev_get_drvdata(jrdev);
 
+	if (jrpriv->hwrng)
+		caam_rng_exit(jrdev->parent);
+
 	/*
 	 * Return EBUSY if job ring already allocated.
 	 */
@@ -514,7 +517,7 @@ static int caam_jr_probe(struct platform_device *pdev)
 	int error;
 
 	jrdev = &pdev->dev;
-	jrpriv = devm_kmalloc(jrdev, sizeof(*jrpriv), GFP_KERNEL);
+	jrpriv = devm_kzalloc(jrdev, sizeof(*jrpriv), GFP_KERNEL);
 	if (!jrpriv)
 		return -ENOMEM;
 
@@ -590,7 +593,7 @@ static int caam_jr_probe(struct platform_device *pdev)
 
 	atomic_set(&jrpriv->tfm_count, 0);
 
-	register_algs(jrdev->parent);
+	register_algs(jrpriv, jrdev->parent);
 
 	return 0;
 }
-- 
2.21.0