From: Benjamin Block <bblock@xxxxxxxxxxxxx> commit a3fd4bfe85fbb67cf4ec1232d0af625ece3c508b upstream. When implementing support for retrieval of local diagnostic data from the FCP channel, the wrong data format was assumed for the temperature of the local SFP+ connector. The Fibre Channel Link Services (FC-LS-3) specification is not clear on the format of the stored integer, and only after consulting the SNIA specification SFF-8472 did we realize it is stored as two's complement. Thus, the used data and display format is wrong, and highly misleading for users when the temperature should drop below 0°C (however unlikely that may be). To fix this, change the data format in `struct fsf_qtcb_bottom_port` from unsigned to signed, and change the printf format string used to generate `zfcp_sysfs_adapter_diag_sfp_temperature_show()` from `%hu` to `%hd`. Link: https://lore.kernel.org/r/d6e3be5428da5c9490cfff4df7cae868bc9f1a7e.1582039501.git.bblock@xxxxxxxxxxxxx Fixes: a10a61e807b0 ("scsi: zfcp: support retrieval of SFP Data via Exchange Port Data") Fixes: 6028f7c4cd87 ("scsi: zfcp: introduce sysfs interface for diagnostics of local SFP transceiver") Cc: <stable@xxxxxxxxxxxxxxx> # 5.5+ Reviewed-by: Jens Remus <jremus@xxxxxxxxxxxxx> Reviewed-by: Fedor Loshakov <loshakov@xxxxxxxxxxxxx> Reviewed-by: Steffen Maier <maier@xxxxxxxxxxxxx> Signed-off-by: Benjamin Block <bblock@xxxxxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/s390/scsi/zfcp_fsf.h | 2 +- drivers/s390/scsi/zfcp_sysfs.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/drivers/s390/scsi/zfcp_fsf.h +++ b/drivers/s390/scsi/zfcp_fsf.h @@ -410,7 +410,7 @@ struct fsf_qtcb_bottom_port { u8 cb_util; u8 a_util; u8 res2; - u16 temperature; + s16 temperature; u16 vcc; u16 tx_bias; u16 tx_power; --- a/drivers/s390/scsi/zfcp_sysfs.c +++ b/drivers/s390/scsi/zfcp_sysfs.c @@ -800,7 +800,7 @@ static ZFCP_DEV_ATTR(adapter_diag, b2b_c static ZFCP_DEV_ATTR(adapter_diag_sfp, _name, 0400, \ zfcp_sysfs_adapter_diag_sfp_##_name##_show, NULL) -ZFCP_DEFINE_DIAG_SFP_ATTR(temperature, temperature, 5, "%hu"); +ZFCP_DEFINE_DIAG_SFP_ATTR(temperature, temperature, 6, "%hd"); ZFCP_DEFINE_DIAG_SFP_ATTR(vcc, vcc, 5, "%hu"); ZFCP_DEFINE_DIAG_SFP_ATTR(tx_bias, tx_bias, 5, "%hu"); ZFCP_DEFINE_DIAG_SFP_ATTR(tx_power, tx_power, 5, "%hu");
