@@ -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;
}
/**
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@intel.com> Reported-by: Julia Lawall <julia.lawall@inria.fr> Closes: https://lore.kernel.org/r/202306221657.BJHEADkz-lkp@intel.com/ Signed-off-by: Damien Le Moal <dlemoal@kernel.org> --- 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(-)