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References: <20180426103430.768-1-david@redhat.com>
From: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Message-ID: <17e55323-8266-2bed-780a-3559d87c8c56@gmail.com>
Date: Thu, 26 Apr 2018 14:41:01 +0300
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Subject: Re: [Qemu-devel] [PATCH v1] pc-dimm: fix error messages if no slots
 were defined
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To: David Hildenbrand <david@redhat.com>, qemu-devel@nongnu.org
Cc: Pankaj Gupta <pagupta@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>, "Michael S . Tsirkin" <mst@redhat.com>, Markus Armbruster <armbru@redhat.com>, Alexander Graf <agraf@suse.de>, qemu-s390x@nongnu.org, qemu-ppc@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>, Marcel Apfelbaum <marcel@redhat.com>, Igor Mammedov <imammedo@redhat.com>, David Gibson <david@gibson.dropbear.id.au>, Richard Henderson <rth@twiddle.net>

Hi David,

On 26/04/2018 13:34, David Hildenbrand wrote:
> If not slots were defined we try to allocate an empty bitmap, which

not -> no

> fails.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> 
> This fixes the queued patch "exec: Allow memory regions with size 0"
> 
>  hw/mem/pc-dimm.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
> index 0119c68e01..f2c140947d 100644
> --- a/hw/mem/pc-dimm.c
> +++ b/hw/mem/pc-dimm.c
> @@ -118,9 +118,15 @@ static int pc_dimm_slot2bitmap(Object *obj, void *opaque)
>  
>  int pc_dimm_get_free_slot(const int *hint, int max_slots, Error **errp)
>  {
> -    unsigned long *bitmap = bitmap_new(max_slots);
> +    unsigned long *bitmap;
>      int slot = 0;
>  
> +    if (max_slots <= 0) {
> +        error_setg(errp, "no free slots available");

Maybe a better error message would be "no slots were allocated"
since max_slots is 0.

Thanks,
Marcel

> +        return slot;
> +    }
> +
> +    bitmap = bitmap_new(max_slots);
>      object_child_foreach(qdev_get_machine(), pc_dimm_slot2bitmap, bitmap);
>  
>      /* check if requested slot is not occupied */
>