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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 1f863e757ee47189e9cef517a09d3045d0f2fd1f..031a77aae19d5a78af5cb73301f309c21a2edee5 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -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;
        }