1. Fix the error check: the alloc length should be > 16
and not > 4
2. Remove duplicated boundary checks which simplify
the fill-in loop
3. Use more of scsi generic API

Signed-off-by: Tomas Winkler <tomas.wink...@intel.com>
---
 drivers/scsi/scsi_debug.c | 119 +++++++++++++++++++++++++++++-----------------
 1 file changed, 76 insertions(+), 43 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 94c18e300135..4dc8caad6cb2 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -3320,63 +3320,96 @@ resp_get_lba_status(struct scsi_cmnd *scp, struct 
sdebug_dev_info *devip)
        return fill_from_dev_buffer(scp, arr, SDEBUG_GET_LBA_STATUS_LEN);
 }
 
-#define SDEBUG_RLUN_ARR_SZ 256
+#define SDEBUG_MAX_RLUNS 31
+#define SDEBUG_RLUN_ARR_SZ ((SDEBUG_MAX_RLUNS * 8) + 8)
 
-static int resp_report_luns(struct scsi_cmnd * scp,
-                           struct sdebug_dev_info * devip)
+static int resp_report_luns(struct scsi_cmnd *scp,
+                           struct sdebug_dev_info *devip)
 {
+       unsigned char *cmd = scp->cmnd;
        unsigned int alloc_len;
-       int lun_cnt, i, upper, num, n, want_wlun, shortish;
+       unsigned char select_report;
+
        u64 lun;
-       unsigned char *cmd = scp->cmnd;
-       int select_report = (int)cmd[2];
        struct scsi_lun *one_lun;
-       unsigned char arr[SDEBUG_RLUN_ARR_SZ];
-       unsigned char * max_addr;
+       u8 arr[SDEBUG_RLUN_ARR_SZ];
+       unsigned int lun_cnt;          /* LUN count */
+       unsigned int wlun_cnt;         /* W_LUN count */
+       unsigned int rlun_cnt;         /* reported LUN count */
+       unsigned int rlen;             /* reported luns in bytes */
+       unsigned int n;
+       int i;
 
        clear_luns_changed_on_target(devip);
-       alloc_len = cmd[9] + (cmd[8] << 8) + (cmd[7] << 16) + (cmd[6] << 24);
-       shortish = (alloc_len < 4);
-       if (shortish || (select_report > 2)) {
-               mk_sense_invalid_fld(scp, SDEB_IN_CDB, shortish ? 6 : 2, -1);
+
+       select_report = cmd[2];
+       alloc_len = get_unaligned_be32(cmd + 6);
+
+       if (alloc_len < 16) {
+               pr_err("alloc len too small %d\n", alloc_len);
+               mk_sense_invalid_fld(scp, SDEB_IN_CDB, 6, -1);
                return check_condition_result;
        }
-       /* can produce response with up to 16k luns (lun 0 to lun 16383) */
-       memset(arr, 0, SDEBUG_RLUN_ARR_SZ);
+
+       if (select_report > 0x02) {
+               pr_err("select report invalid %d\n", select_report);
+               mk_sense_invalid_fld(scp, SDEB_IN_CDB, 2, -1);
+               return check_condition_result;
+       }
+
        lun_cnt = scsi_debug_max_luns;
-       if (1 == select_report)
+       wlun_cnt = 0;
+
+       /* report only w_lun */
+       if (select_report == 0x01)
                lun_cnt = 0;
-       else if (scsi_debug_no_lun_0 && (lun_cnt > 0))
+
+       if (scsi_debug_no_lun_0 && (lun_cnt > 0))
                --lun_cnt;
-       want_wlun = (select_report > 0) ? 1 : 0;
-       num = lun_cnt + want_wlun;
-       arr[2] = ((sizeof(struct scsi_lun) * num) >> 8) & 0xff;
-       arr[3] = (sizeof(struct scsi_lun) * num) & 0xff;
-       n = min((int)((SDEBUG_RLUN_ARR_SZ - 8) /
-                           sizeof(struct scsi_lun)), num);
-       if (n < num) {
-               want_wlun = 0;
+
+       /* report w_lun */
+       if (select_report == 0x01 || select_report == 0x02)
+               wlun_cnt = 1;
+
+       rlun_cnt = lun_cnt + wlun_cnt;
+
+       /* can produce response with up to 16k luns (lun 0 to lun 16383) */
+       n = min_t(int, SDEBUG_MAX_RLUNS, rlun_cnt);
+       if (n < rlun_cnt) {
+               wlun_cnt = 0;
                lun_cnt = n;
        }
-       one_lun = (struct scsi_lun *) &arr[8];
-       max_addr = arr + SDEBUG_RLUN_ARR_SZ;
-       for (i = 0, lun = (scsi_debug_no_lun_0 ? 1 : 0);
-             ((i < lun_cnt) && ((unsigned char *)(one_lun + i) < max_addr));
-            i++, lun++) {
-               upper = (lun >> 8) & 0x3f;
-               if (upper)
-                       one_lun[i].scsi_lun[0] =
-                           (upper | (SAM2_LUN_ADDRESS_METHOD << 6));
-               one_lun[i].scsi_lun[1] = lun & 0xff;
-       }
-       if (want_wlun) {
-               one_lun[i].scsi_lun[0] = (SCSI_W_LUN_REPORT_LUNS >> 8) & 0xff;
-               one_lun[i].scsi_lun[1] = SCSI_W_LUN_REPORT_LUNS & 0xff;
-               i++;
-       }
-       alloc_len = (unsigned char *)(one_lun + i) - arr;
-       return fill_from_dev_buffer(scp, arr,
-                                   min((int)alloc_len, SDEBUG_RLUN_ARR_SZ));
+
+       pr_debug("select_report %d luns = %d wluns = %d no_lun0 %d\n",
+                select_report, lun_cnt, wlun_cnt, scsi_debug_no_lun_0);
+
+       lun = 0LL;
+       /* luns start at offset 8 after the byte length */
+       one_lun = (struct scsi_lun *)&arr[8];
+
+       /* skip lun 0 */
+       if (scsi_debug_no_lun_0)
+               lun++;
+
+       /*
+        * Address method (we use Peripherial = 00b)
+        * 10b - Logical unit
+        * 00b - Peripherial device - Use this one
+        * 01b - Logical device
+        * 11b - reserved
+        */
+       for (i = 0; i < lun_cnt; i++)
+               int_to_scsilun(lun++, one_lun++);
+
+       /* report SCSI_W_LUN_REPORT_LUN */
+       if (wlun_cnt)
+               int_to_scsilun(SCSI_W_LUN_REPORT_LUNS, one_lun++);
+
+       rlen = rlun_cnt * sizeof(struct scsi_lun);
+
+       put_unaligned_be32(rlen, &arr[0]);
+
+       return fill_from_dev_buffer(scp, arr, rlen + 8);
 }
 
 static int resp_xdwriteread(struct scsi_cmnd *scp, unsigned long long lba,
-- 
1.9.3

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