For non-pmp attached devices managed directly by libata, the device number is always 0 or 1 and lower to the maximum number of devices returned by ata_link_max_devices(). However, for libsas managed devices, devices are numbered up to the number of device scanned on an HBA port, while each device has a regular ata/link setup supporting at most 1 device per link. This results in ata_find_dev() always returning NULL except for the first device with device number 0. Fix this by rewriting ata_find_dev() to ignore the device number for non-pmp attached devices with a link with at most 1 device. For these, device number 0 is always used to return the correct ata_device struct of the port link. This change excludes IDE master/slave setups (maximum number of devices per link is 2) and port-multiplier attached devices. Reported-by: Xingui Yang <yangxingui@xxxxxxxxxx> Fixes: 41bda9c98035 ("libata-link: update hotplug to handle PMP links") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx> --- drivers/ata/libata-scsi.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-) diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 7bb12deab70c..3ba9cb258394 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -2696,16 +2696,33 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc) static struct ata_device *ata_find_dev(struct ata_port *ap, int devno) { - if (!sata_pmp_attached(ap)) { - if (likely(devno >= 0 && - devno < ata_link_max_devices(&ap->link))) + if (unlikely(devno < 0)) + return NULL; + + if (likely(!sata_pmp_attached(ap))) { + /* + * For the non PMP case, the maximum number of devices per link + * is 1 (e.g. SATA case), or 2 (IDE master + slave). The former + * case includes libsas hosted devices which are numbered up to + * the number of devices scanned on an HBA port, but with each + * ata device having its own ata port and link. To accommodate + * these, ignore devno and always use device number 0. + */ + switch (ata_link_max_devices(&ap->link)) { + case 1: + return &ap->link.device[0]; + case 2: + if (devno >= 2) + return NULL; return &ap->link.device[devno]; - } else { - if (likely(devno >= 0 && - devno < ap->nr_pmp_links)) - return &ap->pmp_link[devno].device[0]; + default: + return NULL; + } } + if (devno < ap->nr_pmp_links) + return &ap->pmp_link[devno].device[0]; + return NULL; } -- 2.40.1