Reading the 800+ pages of SPC often leads to a brain shutdown and to less than ideal code... This resulted in the checks of the rwcdlp and cdlp fields in scsi_cdl_check_cmd() to have identical if-else branches. Replace this with a comment describing the cases we are interested in and replace the if-else code block with a simple test of the cdlp field that is used as the function return value. Reported-by: kernel test robot <lkp@xxxxxxxxx> Reported-by: Julia Lawall <julia.lawall@xxxxxxxx> Closes: https://lore.kernel.org/r/202306221657.BJHEADkz-lkp@xxxxxxxxx/ Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx> --- Changes from v1: * Reword the comment to follow SPC wording for "One_command parameter data format" drivers/scsi/scsi.c | 37 ++++++++++++++----------------------- 1 file changed, 14 insertions(+), 23 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index c4bf99a842f3..d0911bc28663 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -586,31 +586,22 @@ static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa, if ((buf[1] & 0x03) != 0x03) return false; - /* See SPC-6, one command format of REPORT SUPPORTED OPERATION CODES */ + /* + * See SPC-6, One_command parameter data format for + * REPORT SUPPORTED OPERATION CODES. We have the following cases + * depending on rwcdlp (buf[0] & 0x01) value: + * - rwcdlp == 0: then cdlp indicates support for the A mode page when + * it is equal to 1 and for the B mode page when it is + * equal to 2. + * - rwcdlp == 1: then cdlp indicates support for the T2A mode page + * when it is equal to 1 and for the T2B mode page when + * it is equal to 2. + * Overall, to detect support for command duration limits, we only need + * to check that cdlp is 1 or 2. + */ cdlp = (buf[1] & 0x18) >> 3; - if (buf[0] & 0x01) { - /* rwcdlp == 1 */ - switch (cdlp) { - case 0x01: - /* T2A page */ - return true; - case 0x02: - /* T2B page */ - return true; - } - } else { - /* rwcdlp == 0 */ - switch (cdlp) { - case 0x01: - /* A page */ - return true; - case 0x02: - /* B page */ - return true; - } - } - return false; + return cdlp == 0x01 || cdlp == 0x02; } /** -- 2.40.1
