netdev - Re: [PATCH v2 net-next 2/2] ionic: add devlink firmware update

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Message-ID: <20200905125214.7a13b32b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date:   Sat, 5 Sep 2020 12:52:14 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     Shannon Nelson <snelson@...sando.io>
Cc:     netdev@...r.kernel.org, davem@...emloft.net
Subject: Re: [PATCH v2 net-next 2/2] ionic: add devlink firmware update

On Thu,  3 Sep 2020 17:05:34 -0700 Shannon Nelson wrote:
> +	devlink_flash_update_status_notify(dl, "Downloading", NULL, 0, fw->size);
> +	offset = 0;
> +	next_interval = fw->size / IONIC_FW_INTERVAL_FRACTION;
> +	while (offset < fw->size) {
> +		copy_sz = min_t(unsigned int, buf_sz, fw->size - offset);
> +		mutex_lock(&ionic->dev_cmd_lock);
> +		memcpy_toio(&idev->dev_cmd_regs->data, fw->data + offset, copy_sz);
> +		ionic_dev_cmd_firmware_download(idev,
> +						offsetof(union ionic_dev_cmd_regs, data),
> +						offset, copy_sz);
> +		err = ionic_dev_cmd_wait(ionic, DEVCMD_TIMEOUT);
> +		mutex_unlock(&ionic->dev_cmd_lock);
> +		if (err) {
> +			netdev_err(netdev,
> +				   "download failed offset 0x%x addr 0x%lx len 0x%x\n",
> +				   offset, offsetof(union ionic_dev_cmd_regs, data),
> +				   copy_sz);
> +			NL_SET_ERR_MSG_MOD(extack, "Segment download failed");
> +			goto err_out;
> +		}
> +		offset += copy_sz;
> +
> +		if (offset > next_interval) {
> +			devlink_flash_update_status_notify(dl, "Downloading",
> +							   NULL, offset, fw->size);
> +			next_interval = offset + (fw->size / IONIC_FW_INTERVAL_FRACTION);
> +		}
> +	}
> +	devlink_flash_update_status_notify(dl, "Downloading", NULL, 1, 1);

This is quite awkward. You send a notification with a different size,
and potentially an unnecessary one if last iteration of the loop
triggered offset > next_interval.

Please just add || offset == fw->size to the condition at the end of
the loop and it will always trigger, with the correct length.