From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: Alejandro Lucero <alejandro.lucero@netronome.com>, dev@dpdk.org
Cc: stable@dpdk.org, maxime.coquelin@redhat.com
Subject: Re: [dpdk-stable] [PATCH 1/6] mem: add function for checking memsegs IOVAs addresses
Date: Tue, 3 Jul 2018 10:07:12 +0100 [thread overview]
Message-ID: <ac14782d-72a8-1d8c-66da-2658297a75c7@intel.com> (raw)
In-Reply-To: <1530552423-32301-2-git-send-email-alejandro.lucero@netronome.com>
On 02-Jul-18 6:26 PM, Alejandro Lucero wrote:
> A device can suffer addressing limitations. This functions checks
> memsegs have iovas within the supported range based on dma mask.
>
> PMD should use this during initialization if supported devices
> suffer addressing limitations, returning an error if this function
> returns memsegs out of range.
>
> Another potential usage is for emulated IOMMU hardware with addressing
> limitations.
>
> Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
> ---
<snip>
> + const struct rte_mem_config *mcfg;
> + uint64_t mask;
> + int i;
> + int ret = 0;
> +
> + /* create dma mask */
> + mask = 1ULL << maskbits;
> + mask -= 1;
mask = ~((1ULL << maskbits) - 1);
? IMO this makes it much more clear what you're trying to do.
> +
> + /* get pointer to global configuration */
> + mcfg = rte_eal_get_configuration()->mem_config;
> +
> + for (i = 0; i < RTE_MAX_MEMSEG; i++) {
> + if (mcfg->memseg[i].addr == NULL)
> + break;
> +
> + if (mcfg->memseg[i].iova & ~mask) {
> + ret = -1;
> + break;
> + }
> + }
> +
> + if (!ret)
> + return ret;
> +
> + RTE_LOG(INFO, EAL, "memseg[%d] iova %"PRIx64" out of range:\n",
> + i, mcfg->memseg[i].iova);
> + RTE_LOG(INFO, EAL, "\tusing dma mask %"PRIx64"\n", mask);
> +
> + return -1;
The control flow looks weird to me. You break if iova has any bits that
are in the mask, then you display log messages and return -1. How about
just logging error and returning -1, and simply returning 0 after the loop?
--
Thanks,
Anatoly
next prev parent reply other threads:[~2018-07-03 9:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-02 17:26 [dpdk-stable] [PATH 0/6] Use IOVAs check based on DMA mask Alejandro Lucero
2018-07-02 17:26 ` [dpdk-stable] [PATCH 1/6] mem: add function for checking memsegs IOVAs addresses Alejandro Lucero
2018-07-03 9:07 ` Burakov, Anatoly [this message]
2018-07-03 10:01 ` Alejandro Lucero
2018-07-02 17:26 ` [dpdk-stable] [PATCH 2/6] ethdev: add function for checking IOVAs by a device Alejandro Lucero
2018-07-02 17:27 ` [dpdk-stable] [PATCH 3/6] bus/pci: use IOVAs check when setting IOVA mode Alejandro Lucero
2018-07-03 9:10 ` Burakov, Anatoly
2018-07-03 10:08 ` Alejandro Lucero
2018-07-02 17:27 ` [dpdk-stable] [PATCH 4/6] mem: use address hint for mapping hugepages Alejandro Lucero
2018-07-03 9:17 ` Burakov, Anatoly
2018-07-03 10:44 ` Alejandro Lucero
2018-07-03 10:46 ` Burakov, Anatoly
2018-07-02 17:27 ` [dpdk-stable] [PATCH 5/6] net/nfp: check hugepages IOVAs based on DMA mask Alejandro Lucero
2018-07-02 17:27 ` [dpdk-stable] [PATCH 6/6] net/nfp: support IOVA VA mode Alejandro Lucero
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