From 4f1a22ee7b576a38dc5705837c9b0de0c7b5b064 Mon Sep 17 00:00:00 2001 From: John Garry Date: Fri, 8 Apr 2022 17:04:12 +0800 Subject: libata: Improve ATA queued command allocation Improve ATA queued command allocation as follows: - 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 -1] in the scsi cmnd budget token, so just use that instead. - It is a bit pointless to have ata_qc_new_init() in libata-core.c since it pokes scsi internals, so inline it in ata_scsi_qc_new() (in libata-scsi.c). Also update Doc accordingly. - Use standard SCSI helpers set_host_byte() and set_status_byte() in ata_scsi_qc_new(). Christoph Hellwig originally contributed the change to inline ata_qc_new_init(). Signed-off-by: John Garry Reviewed-by: Christoph Hellwig Signed-off-by: Damien Le Moal --- drivers/ata/libata-scsi.c | 46 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 35 insertions(+), 11 deletions(-) (limited to 'drivers/ata/libata-scsi.c') diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 06c9d90238d9..42cecf95a4e5 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -638,24 +638,48 @@ EXPORT_SYMBOL_GPL(ata_scsi_ioctl); static struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev, struct scsi_cmnd *cmd) { + struct ata_port *ap = dev->link->ap; struct ata_queued_cmd *qc; + int tag; - qc = ata_qc_new_init(dev, scsi_cmd_to_rq(cmd)->tag); - if (qc) { - qc->scsicmd = cmd; - qc->scsidone = scsi_done; - - qc->sg = scsi_sglist(cmd); - qc->n_elem = scsi_sg_count(cmd); + if (unlikely(ap->pflags & ATA_PFLAG_FROZEN)) + goto fail; - if (scsi_cmd_to_rq(cmd)->rq_flags & RQF_QUIET) - qc->flags |= ATA_QCFLAG_QUIET; + if (ap->flags & ATA_FLAG_SAS_HOST) { + /* + * SAS hosts may queue > ATA_MAX_QUEUE commands so use + * unique per-device budget token as a tag. + */ + if (WARN_ON_ONCE(cmd->budget_token >= ATA_MAX_QUEUE)) + goto fail; + tag = cmd->budget_token; } else { - cmd->result = (DID_OK << 16) | SAM_STAT_TASK_SET_FULL; - scsi_done(cmd); + tag = scsi_cmd_to_rq(cmd)->tag; } + qc = __ata_qc_from_tag(ap, tag); + qc->tag = qc->hw_tag = tag; + qc->ap = ap; + qc->dev = dev; + + ata_qc_reinit(qc); + + qc->scsicmd = cmd; + qc->scsidone = scsi_done; + + qc->sg = scsi_sglist(cmd); + qc->n_elem = scsi_sg_count(cmd); + + if (scsi_cmd_to_rq(cmd)->rq_flags & RQF_QUIET) + qc->flags |= ATA_QCFLAG_QUIET; + return qc; + +fail: + set_host_byte(cmd, DID_OK); + set_status_byte(cmd, SAM_STAT_TASK_SET_FULL); + scsi_done(cmd); + return NULL; } static void ata_qc_set_pc_nbytes(struct ata_queued_cmd *qc) -- cgit v1.2.3