Re: [PATCH 1/5] random: Remove unused irq_flags argument from add_interrupt_randomness().

[Jason A. Donenfeld]

On Tue, Dec 7, 2021 at 1:17 PM Sebastian Andrzej Siewior
<bigeasy@xxxxxxxxxxxxx> wrote:
>
> Since commit
>    ee3e00e9e7101 ("random: use registers from interrupted code for CPU's w/o a cycle counter")
>
> the irq_flags argument is no longer used.
>
> Remove unused irq_flags irq_flags.
>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> Cc: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Wei Liu <wei.liu@xxxxxxxxxx>
> Cc: linux-hyperv@xxxxxxxxxxxxxxx
> Cc: x86@xxxxxxxxxx
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---
>  arch/x86/kernel/cpu/mshyperv.c | 2 +-
>  drivers/char/random.c          | 4 ++--
>  drivers/hv/vmbus_drv.c         | 2 +-
>  include/linux/random.h         | 2 +-
>  kernel/irq/handle.c            | 2 +-
>  5 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index ff55df60228f7..2a0f836789118 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -79,7 +79,7 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0)
>         inc_irq_stat(hyperv_stimer0_count);
>         if (hv_stimer0_handler)
>                 hv_stimer0_handler();
> -       add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);
> +       add_interrupt_randomness(HYPERV_STIMER0_VECTOR);
>         ack_APIC_irq();
>
>         set_irq_regs(old_regs);
> diff --git a/drivers/char/random.c b/drivers/char/random.c
> index 605969ed0f965..c8067c264a880 100644
> --- a/drivers/char/random.c
> +++ b/drivers/char/random.c
> @@ -200,7 +200,7 @@
>   *     void add_device_randomness(const void *buf, unsigned int size);
>   *     void add_input_randomness(unsigned int type, unsigned int code,
>   *                                unsigned int value);
> - *     void add_interrupt_randomness(int irq, int irq_flags);
> + *     void add_interrupt_randomness(int irq);
>   *     void add_disk_randomness(struct gendisk *disk);
>   *
>   * add_device_randomness() is for adding data to the random pool that
> @@ -1242,7 +1242,7 @@ static __u32 get_reg(struct fast_pool *f, struct pt_regs *regs)
>         return *ptr;
>  }
>
> -void add_interrupt_randomness(int irq, int irq_flags)
> +void add_interrupt_randomness(int irq)
>  {
>         struct entropy_store    *r;
>         struct fast_pool        *fast_pool = this_cpu_ptr(&irq_randomness);
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 392c1ac4f8193..7ae04ccb10438 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1381,7 +1381,7 @@ static void vmbus_isr(void)
>                         tasklet_schedule(&hv_cpu->msg_dpc);
>         }
>
> -       add_interrupt_randomness(vmbus_interrupt, 0);
> +       add_interrupt_randomness(vmbus_interrupt);
>  }
>
>  static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id)
> diff --git a/include/linux/random.h b/include/linux/random.h
> index f45b8be3e3c4e..c45b2693e51fb 100644
> --- a/include/linux/random.h
> +++ b/include/linux/random.h
> @@ -35,7 +35,7 @@ static inline void add_latent_entropy(void) {}
>
>  extern void add_input_randomness(unsigned int type, unsigned int code,
>                                  unsigned int value) __latent_entropy;
> -extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
> +extern void add_interrupt_randomness(int irq) __latent_entropy;
>
>  extern void get_random_bytes(void *buf, int nbytes);
>  extern int wait_for_random_bytes(void);
> diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
> index 27182003b879c..68c76c3caaf55 100644
> --- a/kernel/irq/handle.c
> +++ b/kernel/irq/handle.c
> @@ -197,7 +197,7 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
>
>         retval = __handle_irq_event_percpu(desc, &flags);
>
> -       add_interrupt_randomness(desc->irq_data.irq, flags);
> +       add_interrupt_randomness(desc->irq_data.irq);
>
>         if (!irq_settings_no_debug(desc))
>                 note_interrupt(desc, retval);
> --
> 2.34.1
>

Thanks for this. Sultan noticed the same thing a while back:
https://lore.kernel.org/lkml/20180430031222.mapajgwprkkr6p36@sultan-box/

I'll apply this and the subsequent one.

Regards,
Jason