Commit 71e3e85c authored by Damien Le Moal's avatar Damien Le Moal Committed by Martin K. Petersen
Browse files

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: default avatarkernel test robot <lkp@intel.com>
Reported-by: default avatarJulia Lawall <julia.lawall@inria.fr>
Closes: https://lore.kernel.org/r/202306221657.BJHEADkz-lkp@intel.com/


Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230623073057.816199-1-dlemoal@kernel.org


Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 4e452369

drivers/scsi/scsi.c

+14 −23
Original line number Original line Diff line number Diff line
@@ -586,31 +586,22 @@ static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa, 
	if ((buf[1] & 0x03) != 0x03)

	if ((buf[1] & 0x03) != 0x03)

		return false;

		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;

	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;

}

}





/**

/**