scsi_debug: fix compare and write errors

Kernel build tools pointed out a memory leak so that has been
fixed and its error paths strengthened with a goto. Testing
showed compare and write was only working for lba=0; correcting
the length of the LBA field fixed that.

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index d81158b..2e32a4c 100644 (file)
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -3044,18 +3044,12 @@ resp_comp_write(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
        u8 num;
        unsigned long iflags;
        int ret;
+       int retval = 0;
 
-       lba = get_unaligned_be32(cmd + 2);
+       lba = get_unaligned_be64(cmd + 2);
        num = cmd[13];          /* 1 to a maximum of 255 logical blocks */
        if (0 == num)
                return 0;       /* degenerate case, not an error */
-       dnum = 2 * num;
-       arr = kzalloc(dnum * lb_size, GFP_ATOMIC);
-       if (NULL == arr) {
-               mk_sense_buffer(scp, ILLEGAL_REQUEST, INSUFF_RES_ASC,
-                               INSUFF_RES_ASCQ);
-               return check_condition_result;
-       }
        if (scsi_debug_dif == SD_DIF_TYPE2_PROTECTION &&
            (cmd[1] & 0xe0)) {
                mk_sense_invalid_opcode(scp);
@@ -3078,6 +3072,13 @@ resp_comp_write(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
                mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB, 0);
                return check_condition_result;
        }
+       dnum = 2 * num;
+       arr = kzalloc(dnum * lb_size, GFP_ATOMIC);
+       if (NULL == arr) {
+               mk_sense_buffer(scp, ILLEGAL_REQUEST, INSUFF_RES_ASC,
+                               INSUFF_RES_ASCQ);
+               return check_condition_result;
+       }
 
        write_lock_irqsave(&atomic_rw, iflags);
 
@@ -3088,24 +3089,24 @@ resp_comp_write(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
        ret = do_device_access(scp, 0, dnum, true);
        fake_storep = fake_storep_hold;
        if (ret == -1) {
-               write_unlock_irqrestore(&atomic_rw, iflags);
-               kfree(arr);
-               return DID_ERROR << 16;
+               retval = DID_ERROR << 16;
+               goto cleanup;
        } else if ((ret < (dnum * lb_size)) &&
                 (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts))
                sdev_printk(KERN_INFO, scp->device, "%s: compare_write: cdb "
                            "indicated=%u, IO sent=%d bytes\n", my_name,
                            dnum * lb_size, ret);
        if (!comp_write_worker(lba, num, arr)) {
-               write_unlock_irqrestore(&atomic_rw, iflags);
-               kfree(arr);
                mk_sense_buffer(scp, MISCOMPARE, MISCOMPARE_VERIFY_ASC, 0);
-               return check_condition_result;
+               retval = check_condition_result;
+               goto cleanup;
        }
        if (scsi_debug_lbp())
                map_region(lba, num);
+cleanup:
        write_unlock_irqrestore(&atomic_rw, iflags);
-       return 0;
+       kfree(arr);
+       return retval;
 }
 
 struct unmap_block_desc {