On Tue, Jul 22, 2014 at 7:10 PM, Mike Qiu <qiudayu@xxxxxxxxxxxxxxxxxx> wrote: > On 07/22/2014 11:42 PM, Tejun Heo wrote: >> >> Hello, >> >> (cc'ing Dan) >> >> On Tue, Jul 22, 2014 at 10:50:19AM -0400, Mike Qiu wrote: >>> >>> The can_queue in scsi_host can be more than ATA_MAX_QUEUE (32), >>> for example, in ipr, it can be 100 or more. >>> >>> Also, some drivers, like ipr driver, haven't filled the field >>> scsi_host in ata_port, and will lead a call trace, so add >>> check for that. >>> >>> Signed-off-by: Mike Qiu <qiudayu@xxxxxxxxxxxxxxxxxx> >>> --- >>> drivers/ata/libata-core.c | 15 ++++----------- >>> 1 file changed, 4 insertions(+), 11 deletions(-) >>> >>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c >>> index 259d879..a5b9c70 100644 >>> --- a/drivers/ata/libata-core.c >>> +++ b/drivers/ata/libata-core.c >>> @@ -4734,7 +4734,10 @@ static struct ata_queued_cmd *ata_qc_new(struct >>> ata_port *ap) >>> struct ata_queued_cmd *qc = NULL; >>> unsigned int i, tag, max_queue; >>> - max_queue = ap->scsi_host->can_queue; >>> + if (ap->scsi_host && ap->scsi_host->can_queue <= ATA_MAX_QUEUE) >>> + max_queue = ap->scsi_host->can_queue; >>> + else >>> + max_queue = ATA_MAX_QUEUE; >>> /* no command while frozen */ >>> if (unlikely(ap->pflags & ATA_PFLAG_FROZEN)) >>> @@ -6109,16 +6112,6 @@ int ata_host_register(struct ata_host *host, >>> struct scsi_host_template *sht) >>> { >>> int i, rc; >>> - /* >>> - * The max queue supported by hardware must not be greater than >>> - * ATA_MAX_QUEUE. >>> - */ >>> - if (sht->can_queue > ATA_MAX_QUEUE) { >>> - dev_err(host->dev, "BUG: the hardware max queue is too >>> large\n"); >>> - WARN_ON(1); >>> - return -EINVAL; >>> - } >>> - >> >> So, ummm, I really don't like that we're adding the conditionals to >> the hot path (yeah, its implementation is slow but still). Maybe we > > > Yes, agree ..., not a good idea to do this... > ...also, seems incomplete given ata_port.qcmd[] is still limited to ATA_MAX_QUEUE. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html