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Commit aa18da8b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Tejun Heo
Browse files

libata: avoid global response buffer in atapi_qc_complete 



We only need to look at 4 bytes of the inquiry response for ATAPI
devices.  Instead of using the global ata_scsi_rbuf just use a
a stack buffer.  Also factor the fixup into it's own little helper
function to make it more readable.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent fb1b8b11

drivers/ata/libata-scsi.c

+22 −24
Original line number Diff line number Diff line
@@ -2873,6 +2873,26 @@ static void atapi_request_sense(struct ata_queued_cmd *qc) 
	DPRINTK("EXIT\n");

}



/*

 * ATAPI devices typically report zero for their SCSI version, and sometimes

 * deviate from the spec WRT response data format.  If SCSI version is

 * reported as zero like normal, then we make the following fixups:

 *   1) Fake MMC-5 version, to indicate to the Linux scsi midlayer this is a

 *	modern device.

 *   2) Ensure response data format / ATAPI information are always correct.

 */

static void atapi_fixup_inquiry(struct scsi_cmnd *cmd)

{

	u8 buf[4];



	sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd), buf, 4);

	if (buf[2] == 0) {

		buf[2] = 0x5;

		buf[3] = 0x32;

	}

	sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd), buf, 4);

}



static void atapi_qc_complete(struct ata_queued_cmd *qc)

{

	struct scsi_cmnd *cmd = qc->scsicmd;
@@ -2927,30 +2947,8 @@ static void atapi_qc_complete(struct ata_queued_cmd *qc) 
		 */

		ata_gen_passthru_sense(qc);

	} else {

		u8 *scsicmd = cmd->cmnd;



		if ((scsicmd[0] == INQUIRY) && ((scsicmd[1] & 0x03) == 0)) {

			unsigned long flags;

			u8 *buf;



			buf = ata_scsi_rbuf_get(cmd, true, &flags);



	/* ATAPI devices typically report zero for their SCSI version,

	 * and sometimes deviate from the spec WRT response data

	 * format.  If SCSI version is reported as zero like normal,

	 * then we make the following fixups:  1) Fake MMC-5 version,

	 * to indicate to the Linux scsi midlayer this is a modern

	 * device.  2) Ensure response data format / ATAPI information

	 * are always correct.

	 */

			if (buf[2] == 0) {

				buf[2] = 0x5;

				buf[3] = 0x32;

			}



			ata_scsi_rbuf_put(cmd, true, &flags);

		}



		if (cmd->cmnd[0] == INQUIRY && (cmd->cmnd[1] & 0x03) == 0)

			atapi_fixup_inquiry(cmd);

		cmd->result = SAM_STAT_GOOD;

	}