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Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v2 1/2] libata: Use scsi cmnd budget token for qc tag for SAS host Content-Language: en-US To: John Garry , hch@lst.de Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-doc@vger.kernel.org, linux-scsi@vger.kernel.org References: <1649083990-207133-1-git-send-email-john.garry@huawei.com> <1649083990-207133-2-git-send-email-john.garry@huawei.com> From: Damien Le Moal Organization: Western Digital Research In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/6/22 16:12, John Garry wrote: > On 06/04/2022 02:39, Damien Le Moal wrote: >> On 4/4/22 23:53, John Garry wrote: >>> For attaining a qc tag for a SAS host we need to allocate a bit in >>> ata_port.sas_tag_allocated bitmap. >>> >>> However we already have a unique tag per device in range >>> [0, ATA_MAX_QUEUE) in the scsi cmnd budget token, so just use that >>> instead. >> >> The valid range is [0, ATA_MAX_QUEUE - 1]. Tag ATA_MAX_QUEUE is >> ATA_TAG_INTERNAL which is never allocated as a valid device tag but >> used directly in ata_exec_internal(). > > But that is what I have in [0, ATA_MAX_QUEUE), which is same as [0, > ATA_MAX_QUEUE - 1]. Oh ! I missed the ")" ! I would prefer an explicit [0, ATA_MAX_QUEUE - 1] to be clear :) > > Thanks, > john -- Damien Le Moal Western Digital Research