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{
    "id": 105572,
    "url": "http://patches.dpdk.org/api/covers/105572/?format=api",
    "web_url": "http://patches.dpdk.org/project/dpdk/cover/20220103142201.475552-1-amo@semihalf.com/",
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        "id": 1,
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        "name": "DPDK",
        "link_name": "dpdk",
        "list_id": "dev.dpdk.org",
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    "msgid": "<20220103142201.475552-1-amo@semihalf.com>",
    "list_archive_url": "https://inbox.dpdk.org/dev/20220103142201.475552-1-amo@semihalf.com",
    "date": "2022-01-03T14:22:00",
    "name": "[0/1] Minor mistake in ring (en|de)queueing",
    "submitter": {
        "id": 1112,
        "url": "http://patches.dpdk.org/api/people/1112/?format=api",
        "name": "Andrzej Ostruszka",
        "email": "amo@semihalf.com"
    },
    "mbox": "http://patches.dpdk.org/project/dpdk/cover/20220103142201.475552-1-amo@semihalf.com/mbox/",
    "series": [
        {
            "id": 21050,
            "url": "http://patches.dpdk.org/api/series/21050/?format=api",
            "web_url": "http://patches.dpdk.org/project/dpdk/list/?series=21050",
            "date": "2022-01-03T14:22:00",
            "name": "Minor mistake in ring (en|de)queueing",
            "version": 1,
            "mbox": "http://patches.dpdk.org/series/21050/mbox/"
        }
    ],
    "comments": "http://patches.dpdk.org/api/covers/105572/comments/",
    "headers": {
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        "From": "Andrzej Ostruszka <amo@semihalf.com>",
        "To": "dev@dpdk.org",
        "Cc": "upstream@semihalf.com,\n\tAndrzej Ostruszka <amo@semihalf.com>",
        "Subject": "[PATCH 0/1] Minor mistake in ring (en|de)queueing",
        "Date": "Mon,  3 Jan 2022 15:22:00 +0100",
        "Message-Id": "<20220103142201.475552-1-amo@semihalf.com>",
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        "Errors-To": "dev-bounces@dpdk.org"
    },
    "content": "Hi all,\n\nRecently I was going through the ring implementation and I believe I've\nfound a small mistake.  Not a functional error, just a slightly\nsuboptimal behaviour for the specific case when we want to enqueue\nexactly the number of elements that we can before wrapping to the ring\nbeginning (the same goes for dequeueing).\n\nImagine we have a ring of size 16 depicted below with indexes underneath\nand consumer/producer pointing as shown.\n\n|  ******        |\n 0123456789ABCDEF\n   ^     ^\n   c     p\n\nNow if we try to enqueue 8 elements we will end up at the check:\n\n\tif (likely(idx + n < size)) {\n\nwhere idx (=8) is a producer head and n=8.  We will fail this check\neven though we have the case of 8 elements available without wrapping to\nthe beginning of the ring.\n\nI hope I'm not completely off the base here :), if I'm not then the\nsubsequent patch attempts to fix this.\n\nWit regards\nAndrzej Ostruszka\n\nAndrzej Ostruszka (1):\n  ring: fix off by 1 mistake\n\n lib/ring/rte_ring_elem_pvt.h | 12 ++++++------\n 1 file changed, 6 insertions(+), 6 deletions(-)"
}