Re: [Qemu-devel] [PATCH v3 12/46] ivshmem: simplify around increase_dynamic_storage()

[Claudio Fontana]

On 15.09.2015 18:07, address@hidden wrote:
> From: Marc-André Lureau <address@hidden>
> 
> Set the number of peers and array allocation in a single place. Rename
> to better reflect the function content.
> 
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  hw/misc/ivshmem.c | 27 +++++++++++----------------
>  1 file changed, 11 insertions(+), 16 deletions(-)
> 
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index cd2c4bc..889a199 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -417,30 +417,28 @@ static void close_guest_eventfds(IVShmemState *s, int 
> posn)
>  
>  /* this function increase the dynamic storage need to store data about other
>   * guests */
> -static int increase_dynamic_storage(IVShmemState *s, int new_min_size)
> +static int resize_peers(IVShmemState *s, int new_min_size)
>  {
>  
> -    int j, old_nb_alloc;
> +    int j, old_size;
>  
>      /* limit number of max peers */
>      if (new_min_size <= 0 || new_min_size > IVSHMEM_MAX_PEERS) {
>          return -1;
>      }
> -
> -    old_nb_alloc = s->nb_peers;
> -
> -    if (new_min_size >= s->nb_peers) {
> -        /* +1 because #new_min_size is used as last array index */
> -        s->nb_peers = new_min_size + 1;
> -    } else {
> +    if (new_min_size <= s->nb_peers) {
>          return 0;
>      }
>  
> +    old_size = s->nb_peers;
> +    s->nb_peers = new_min_size;
> +
>      IVSHMEM_DPRINTF("bumping storage to %d guests\n", s->nb_peers);
> +
>      s->peers = g_realloc(s->peers, s->nb_peers * sizeof(Peer));
>  
>      /* zero out new pointers */
> -    for (j = old_nb_alloc; j < s->nb_peers; j++) {
> +    for (j = old_size; j < s->nb_peers; j++) {
>          s->peers[j].eventfds = NULL;
>          s->peers[j].nb_eventfds = 0;
>      }
> @@ -508,8 +506,8 @@ static void ivshmem_read(void *opaque, const uint8_t 
> *buf, int size)
>  
>      /* make sure we have enough space for this guest */
>      if (incoming_posn >= s->nb_peers) {
> -        if (increase_dynamic_storage(s, incoming_posn) < 0) {
> -            error_report("increase_dynamic_storage() failed");
> +        if (resize_peers(s, incoming_posn + 1) < 0) {
> +            error_report("failed to resize peers array");
>              if (incoming_fd != -1) {
>                  close(incoming_fd);
>              }
> @@ -812,12 +810,9 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error 
> **errp)
>          }
>  
>          /* we allocate enough space for 16 guests and grow as needed */
> -        s->nb_peers = 16;
> +        resize_peers(s, 16);
>          s->vm_id = -1;
>  
> -        /* allocate/initialize space for interrupt handling */
> -        s->peers = g_malloc0(s->nb_peers * sizeof(Peer));
> -
>          pci_register_bar(dev, 2, attr, &s->bar);
>  
>          s->eventfd_chr = g_malloc0(s->vectors * sizeof(CharDriverState *));
> 

Reviewed-by: Claudio Fontana <address@hidden>