On Mon, 2011-10-17 at 01:28 +0300, Dan Carpenter wrote:
> On Fri, Oct 14, 2011 at 11:36:36PM -0700, Joe Perches wrote:
[]
> >     case 0:
> >             if (bytes_recvd <= 0)
> >                     goto loop;
> In the original we called break here (which is equivelent to a
> return).  Btw setting a stack variable and then returning immediately
> like the original code did is pointless.

OK, return it is.

Perhaps this is better.  (two of the breaks could be goto loop)

I did add a couple of checks to make sure kmalloc'd
memory was always freed.

Another possible simplification is to always use kmalloc
instead of using stack and/or kmalloc.

static void mousevsc_on_channel_callback(void *context)
{
        static const int packetSize = 0x100;
        unsigned char packet[packetSize];
        int ret;
        struct hv_device *device = (struct hv_device *)context;
        u32 bytes_recvd;
        u64 req_id;
        struct vmpacket_descriptor *desc;
        unsigned char *buffer = packet;
        int bufferlen = packetSize;
        bool malloced =  false;

loop:
        ret = vmbus_bus_recvpacket_raw(device->channel, buffer, bufferlen,
                                       &bytes_recvd, &req_id);
        switch (ret) {
        case -ENOBUFS:          /* Handle large packet */

                if (malloced)   /* Maybe repeated -ENOBUFS ? */
                        kfree(buffer);

                bufferlen = bytes_recvd;
                buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
                if (!buffer)
                        return;
                malloced = true;
                break;

        case 0:
                if (bytes_recvd <= 0) {
                        if (malloced)
                                kfree(buffer);
                        return;
                }

                desc = (struct vmpacket_descriptor *)buffer;

                switch (desc->type) {
                case VM_PKT_DATA_INBAND:
                        mousevsc_on_receive(device, desc);
                        break;
                default:
                        pr_err("unhandled packet type %d, tid %llx len %d\n",
                               desc->type, req_id, bytes_recvd);
                        break;
                }
                /* reset to original buffers */
                if (malloced) {
                        kfree(buffer);
                        malloced = false;
                        buffer = packet;
                        bufferlen = packetSize;
                }
                break;
        }

        goto loop;
}


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