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    Subject[PATCH v9 3/9] crypto: caam - drop global context pointer and init_done
    Date
    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@gmail.com>
    Cc: Chris Healy <cphealy@gmail.com>
    Cc: Lucas Stach <l.stach@pengutronix.de>
    Cc: Horia Geantă <horia.geanta@nxp.com>
    Cc: Herbert Xu <herbert@gondor.apana.org.au>
    Cc: Iuliana Prodan <iuliana.prodan@nxp.com>
    Cc: linux-crypto@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org
    Cc: linux-imx@nxp.com
    ---
    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
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