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authorDamien Le Moal <dlemoal@kernel.org>2023-06-23 10:30:57 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2023-06-29 04:47:09 +0300
commit71e3e85ccf2b816e612c94b7460309dc5007caef (patch)
treec77309c8637db7a6d6a2613ad2785d371bd3676c /drivers/scsi
parent4e45236982bcc3ce8a0ea719e1159cc5c935eb94 (diff)
downloadlinux-71e3e85ccf2b816e612c94b7460309dc5007caef.tar.xz
scsi: core: Simplify scsi_cdl_check_cmd()
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> Link: https://lore.kernel.org/r/20230623073057.816199-1-dlemoal@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/scsi.c37
1 files 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;
}
/**