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From: Richard Henderson <rth@twiddle.net>
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Date: Sun, 24 Apr 2016 13:01:31 -0700
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Subject: Re: [Qemu-devel] [PATCH v3 08/11] qht: QEMU's fast,
 resizable and scalable Hash Table
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To: "Emilio G. Cota" <cota@braap.org>, QEMU Developers <qemu-devel@nongnu.org>, MTTCG Devel <mttcg@greensocs.com>
Cc: =?UTF-8?Q?Alex_Benn=c3=a9e?= <alex.bennee@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Peter Crosthwaite <crosthwaite.peter@gmail.com>, Peter Maydell <peter.maydell@linaro.org>, Sergey Fedorov <serge.fdrv@gmail.com>

On 04/19/2016 04:07 PM, Emilio G. Cota wrote:
> +static void qht_insert__locked(struct qht *ht, struct qht_map *map,
> +                               struct qht_bucket *head, void *p, uint32_t hash)
> +{
> +    struct qht_bucket *b = head;
> +    struct qht_bucket *prev = NULL;
> +    struct qht_bucket *new = NULL;
> +    int i;
> +
> +    for (;;) {
> +        if (b == NULL) {
> +            b = qemu_memalign(QHT_BUCKET_ALIGN, sizeof(*b));
> +            memset(b, 0, sizeof(*b));
> +            new = b;
> +        }
> +        for (i = 0; i < QHT_BUCKET_ENTRIES; i++) {
> +            if (b->hashes[i]) {
> +                continue;
> +            }

Surely that's b->pointers[i] != NULL.  We've made no provision that the hash 
function must return non-zero.

> +static inline bool qht_remove__locked(struct qht_map *map, struct qht_bucket *b,
> +                                      const void *p, uint32_t hash)
> +{
> +    int i;
> +
> +    do {
> +        for (i = 0; i < QHT_BUCKET_ENTRIES; i++) {
> +            if (b->hashes[i] == hash && b->pointers[i] == p) {

Don't you only need to test p here?


r~