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SubjectRe: [PATCH v3 6/7] ocxl: move event_fd handling to frontend
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Le 25/03/2019 à 06:44, Alastair D'Silva a écrit :
> From: Alastair D'Silva <alastair@d-silva.org>
>
> Event_fd is only used in the driver frontend, so it does not
> need to exist in the backend code. Relocate it to the frontend
> and provide an opaque mechanism for consumers instead.
>
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
> drivers/misc/ocxl/afu_irq.c | 76 ++++++++++++++++++-------------
> drivers/misc/ocxl/file.c | 22 ++++++++-
> drivers/misc/ocxl/ocxl_internal.h | 5 --
> include/misc/ocxl.h | 46 +++++++++++++++++++
> 4 files changed, 111 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/misc/ocxl/afu_irq.c b/drivers/misc/ocxl/afu_irq.c
> index 2d410cd6f817..d71e62df7d31 100644
> --- a/drivers/misc/ocxl/afu_irq.c
> +++ b/drivers/misc/ocxl/afu_irq.c
> @@ -1,7 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0+
> // Copyright 2017 IBM Corp.
> #include <linux/interrupt.h>
> -#include <linux/eventfd.h>
> +#include <asm/pnv-ocxl.h>
> #include "ocxl_internal.h"
> #include "trace.h"
>
> @@ -11,7 +11,9 @@ struct afu_irq {
> unsigned int virq;
> char *name;
> u64 trigger_page;
> - struct eventfd_ctx *ev_ctx;
> + irqreturn_t (*handler)(void *private);
> + void (*free_private)(void *private);
> + void *private;
> };
>
> int ocxl_irq_offset_to_id(struct ocxl_context *ctx, u64 offset)
> @@ -24,14 +26,43 @@ u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id)
> return ctx->afu->irq_base_offset + (irq_id << PAGE_SHIFT);
> }
>
> +int ocxl_irq_set_handler(struct ocxl_context *ctx, int irq_id,
> + irqreturn_t (*handler)(void *private),
> + void (*free_private)(void *private),
> + void *private)
> +{
> + struct afu_irq *irq;
> + int rc;
> +
> + mutex_lock(&ctx->irq_lock);
> + irq = idr_find(&ctx->irq_idr, irq_id);
> + if (!irq) {
> + rc = -EINVAL;
> + goto unlock;
> + }
> +
> + irq->handler = handler;
> + irq->private = private;
> +
> + rc = 0;
> + goto unlock;


That goto is too much.


> +
> +unlock:
> + mutex_unlock(&ctx->irq_lock);
> + return rc;
> +}
> +EXPORT_SYMBOL_GPL(ocxl_irq_set_handler);
> +
> static irqreturn_t afu_irq_handler(int virq, void *data)
> {
> struct afu_irq *irq = (struct afu_irq *) data;
>
> trace_ocxl_afu_irq_receive(virq);
> - if (irq->ev_ctx)
> - eventfd_signal(irq->ev_ctx, 1);
> - return IRQ_HANDLED;
> +
> + if (irq->handler)
> + return irq->handler(irq->private);
> +
> + return IRQ_HANDLED; // Just drop it on the ground
> }
>
> static int setup_afu_irq(struct ocxl_context *ctx, struct afu_irq *irq)
> @@ -118,6 +149,8 @@ int ocxl_afu_irq_alloc(struct ocxl_context *ctx, int *irq_id)
> return rc;
> }
>
> +EXPORT_SYMBOL_GPL(ocxl_afu_irq_alloc);


nit: checkpatch doesn't like the empty line between the function and its
symbol export. Also true for a few other symbols in that file.



> diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
> index a8fe0ce4ea67..1b48e9d63abb 100644
> --- a/include/misc/ocxl.h
> +++ b/include/misc/ocxl.h
> @@ -161,6 +161,52 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr,
> */
> int ocxl_context_detach(struct ocxl_context *ctx);
>
> +// AFU IRQs
> +
> +/**
> + * Allocate an IRQ associated with an AFU context
> + * @ctx: the AFU context
> + * @irq_id: out, the IRQ ID
> + *
> + * Returns 0 on success, negative on failure
> + */
> +extern int ocxl_afu_irq_alloc(struct ocxl_context *ctx, int *irq_id);
> +
> +/**
> + * Frees an IRQ associated with an AFU context
> + * @ctx: the AFU context
> + * @irq_id: the IRQ ID
> + *
> + * Returns 0 on success, negative on failure
> + */
> +extern int ocxl_afu_irq_free(struct ocxl_context *ctx, int irq_id);
> +
> +/**
> + * Gets the address of the trigger page for an IRQ
> + * This can then be provided to an AFU which will write to that
> + * page to trigger the IRQ.
> + * @ctx: The AFU context that the IRQ is associated with
> + * @irq_id: The IRQ ID
> + *
> + * returns the trigger page address, or 0 if the IRQ is not valid
> + */
> +extern u64 ocxl_afu_irq_get_addr(struct ocxl_context *ctx, int irq_id);
> +
> +/**
> + * Provide a callback to be called when an IRQ is triggered
> + * @ctx: The AFU context that the IRQ is associated with
> + * @irq_id: The IRQ ID
> + * @handler: the callback to be called when the IRQ is triggered
> + * @free_private: the callback to be called when the IRQ is freed

We should mention free_private can be NULL, in which case it is ignored.

Fred

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