netdev - RE: [PATCH net-next V3 08/18] liquidio: CN23XX queue manipulation

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Date:   Mon, 22 Aug 2016 16:45:00 +0000
From:   Yuval Mintz <Yuval.Mintz@...gic.com>
To:     Raghu Vatsavayi <rvatsavayi@...iumnetworks.com>,
        David Miller <davem@...emloft.net>
CC:     netdev <netdev@...r.kernel.org>,
        Derek Chickles <derek.chickles@...iumnetworks.com>,
        Satanand Burla <satananda.burla@...iumnetworks.com>,
        Felix Manlunas <felix.manlunas@...iumnetworks.com>,
        Raghu Vatsavayi <raghu.vatsavayi@...iumnetworks.com>
Subject: RE: [PATCH net-next V3 08/18] liquidio: CN23XX queue manipulation

> +		while ((READ_ONCE(reg_val) & CN23XX_PKT_INPUT_CTL_RST)
> &&
> +		       !(READ_ONCE(reg_val) & CN23XX_PKT_INPUT_CTL_QUIET))
> {
> +			WRITE_ONCE(reg_val, octeon_read_csr64(
> +			    oct, CN23XX_SLI_IQ_PKT_CONTROL64(q_no)));
> +		}
Busy-reading registers without any timeout. Couldn't there be corner cases [PCI errors, etc.]?
[This is a recurring event in this patch]

> +static void cn23xx_disable_io_queues(struct octeon_device *oct) {
> +	u64 d64 = 0ULL;
> +	u32 d32 = 0ULL;
While true, why bother with the ULLs?

> +
> +		/* Reset the doorbell register for this Input Queue. */
> +		octeon_write_csr(oct, CN23XX_SLI_IQ_DOORBELL(q_no),
> 0xFFFFFFFF);
> +		while (((octeon_read_csr64(
> +			    oct, CN23XX_SLI_IQ_DOORBELL(q_no))) != 0ULL) &&
!, not != 0.

> CN23XX_SLI_PKT_IOQ_RING_RST));
> +		while (!(READ_ONCE(d64) & (0x1ULL << q_no)) && loop--) {
You can use BIT_ULL for this

> +		/* Reset the doorbell register for this Output Queue. */
> +		octeon_write_csr(oct, CN23XX_SLI_OQ_PKTS_CREDIT(q_no),
> +				 0xFFFFFFFF);
> +		while (((octeon_read_csr64(
> +			    oct, CN23XX_SLI_OQ_PKTS_CREDIT(q_no))) != 0ULL)
!, not != 0.