From: Damien Le Moal dlemoal@kernel.org
commit 7f875850f20a42f488840c9df7af91ef7db2d576 upstream.
For devices not attached to a port multiplier and managed directly by libata, the device number passed to ata_find_dev() must always be lower than the maximum number of devices returned by ata_link_max_devices(). That is 1 for SATA devices or 2 for an IDE link with master+slave devices. This device number is the SCSI device ID which matches these constraints as the IDs are generated per port and so never exceed the maximum number of devices for the link being used.
However, for libsas managed devices, SCSI device IDs are assigned per struct scsi_host, leading to device IDs for SATA devices that can be well in excess of libata per-link maximum number of devices. This results in ata_find_dev() to always return NULL for libsas managed devices except for the first device of the target scsi_host with ID (device number) equal to 0. This issue is visible by executing the hdparm utility, which fails. E.g.:
hdparm -i /dev/sdX /dev/sdX: HDIO_GET_IDENTITY failed: No message of desired type
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, that is SATA devices. For these, the device number 0 is always used to return the correct pointer to the struct ata_device of the port link. This change excludes IDE master/slave setups (maximum number of devices per link is 2) and port-multiplier attached devices. Also, to be consistant with the fact that SCSI device IDs and channel numbers used as device numbers are both unsigned int, change the devno argument of ata_find_dev() to unsigned int.
Reported-by: Xingui Yang yangxingui@huawei.com Fixes: 41bda9c98035 ("libata-link: update hotplug to handle PMP links") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal dlemoal@kernel.org Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/ata/libata-scsi.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-)
--- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -2698,18 +2698,36 @@ static unsigned int atapi_xlat(struct at return 0; }
-static struct ata_device *ata_find_dev(struct ata_port *ap, int devno) +static struct ata_device *ata_find_dev(struct ata_port *ap, unsigned int devno) { - if (!sata_pmp_attached(ap)) { - if (likely(devno >= 0 && - devno < ata_link_max_devices(&ap->link))) + /* + * For the non-PMP case, ata_link_max_devices() returns 1 (SATA case), + * or 2 (IDE master + slave case). However, the former case includes + * libsas hosted devices which are numbered per scsi host, leading + * to devno potentially being larger than 0 but with each struct + * ata_device having its own struct ata_port and struct ata_link. + * To accommodate these, ignore devno and always use device number 0. + */ + if (likely(!sata_pmp_attached(ap))) { + int link_max_devices = ata_link_max_devices(&ap->link); + + if (link_max_devices == 1) + return &ap->link.device[0]; + + if (devno < link_max_devices) return &ap->link.device[devno]; - } else { - if (likely(devno >= 0 && - devno < ap->nr_pmp_links)) - return &ap->pmp_link[devno].device[0]; + + return NULL; }
+ /* + * For PMP-attached devices, the device number corresponds to C + * (channel) of SCSI [H:C:I:L], indicating the port pmp link + * for the device. + */ + if (devno < ap->nr_pmp_links) + return &ap->pmp_link[devno].device[0]; + return NULL; }