mkbufpool.c

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#include <xinu.h>

bpid32 mkbufpool(int32 bufsiz, int32 numbufs)
{
    intmask mask;          /* Saved interrupt mask      */
    bpid32 poolid;         /* ID of pool that is created    */
    struct bpentry *bpptr; /* Pointer to entry in buftab    */
    char *buf;             /* Pointer to memory for buffer  */

    mask = disable();
    if (bufsiz < BP_MINB || bufsiz > BP_MAXB || numbufs < 1 || numbufs > BP_MAXN || nbpools >= NBPOOLS)
    {
        restore(mask);
        return (bpid32)SYSERR;
    }
    /* Round request to a multiple of 4 bytes */

    bufsiz = ((bufsiz + 3) & (~3));

    buf = (char *)getmem(numbufs * (bufsiz + sizeof(bpid32)));
    if ((int32)buf == SYSERR)
    {
        restore(mask);
        return (bpid32)SYSERR;
    }
    poolid = nbpools++;
    bpptr = &buftab[poolid];
    bpptr->bpnext = (struct bpentry *)buf;
    bpptr->bpsize = bufsiz;
    if ((bpptr->bpsem = semcreate(numbufs)) == SYSERR)
    {
        freemem(buf, numbufs * (bufsiz + sizeof(bpid32)));
        nbpools--;
        restore(mask);
        return (bpid32)SYSERR;
    }
    bufsiz += sizeof(bpid32);
    for (numbufs--; numbufs > 0; numbufs--)
    {
        bpptr = (struct bpentry *)buf;
        buf += bufsiz;
        bpptr->bpnext = (struct bpentry *)buf;
    }
    bpptr = (struct bpentry *)buf;
    bpptr->bpnext = (struct bpentry *)NULL;
    restore(mask);
    return poolid;
}