1 files changed, 50 insertions, 66 deletions

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 70bcee6516c2..c98559eceade 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1468,25 +1468,53 @@ static int resp_log_sense(struct scsi_cmnd * scp,
                     min(len, SDEBUG_MAX_INQ_ARR_SZ));
 }
 
-static int resp_read(struct scsi_cmnd * SCpnt, unsigned long long lba,
-                     unsigned int num, struct sdebug_dev_info * devip)
+static int check_device_access_params(struct sdebug_dev_info *devi,
+                                      unsigned long long lba, unsigned int num)
 {
-        unsigned long iflags;
-        unsigned int block, from_bottom;
-        unsigned long long u;
-        int ret;
-
         if (lba + num > sdebug_capacity) {
-                mk_sense_buffer(devip, ILLEGAL_REQUEST, ADDR_OUT_OF_RANGE,
-                                0);
+                mk_sense_buffer(devi, ILLEGAL_REQUEST, ADDR_OUT_OF_RANGE, 0);
                 return check_condition_result;
         }
         /* transfer length excessive (tie in to block limits VPD page) */
         if (num > sdebug_store_sectors) {
-                mk_sense_buffer(devip, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
-                                0);
+                mk_sense_buffer(devi, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB, 0);
                 return check_condition_result;
         }
+        return 0;
+}
+
+static int do_device_access(struct scsi_cmnd *scmd,
+                            struct sdebug_dev_info *devi,
+                            unsigned long long lba, unsigned int num, int write)
+{
+        int ret;
+        unsigned int block, rest = 0;
+        int (*func)(struct scsi_cmnd *, unsigned char *, int);
+
+        func = write ? fetch_to_dev_buffer : fill_from_dev_buffer;
+
+        block = do_div(lba, sdebug_store_sectors);
+        if (block + num > sdebug_store_sectors)
+                rest = block + num - sdebug_store_sectors;
+
+        ret = func(scmd, fake_storep + (block * SECT_SIZE),
+                   (num - rest) * SECT_SIZE);
+        if (!ret && rest)
+                ret = func(scmd, fake_storep, rest * SECT_SIZE);
+
+        return ret;
+}
+
+static int resp_read(struct scsi_cmnd *SCpnt, unsigned long long lba,
+                     unsigned int num, struct sdebug_dev_info *devip)
+{
+        unsigned long iflags;
+        int ret;
+
+        ret = check_device_access_params(devip, lba, num);
+        if (ret)
+                return ret;
+
         if ((SCSI_DEBUG_OPT_MEDIUM_ERR & scsi_debug_opts) &&
             (lba <= OPT_MEDIUM_ERR_ADDR) &&
             ((lba + num) > OPT_MEDIUM_ERR_ADDR)) {
@@ -1505,74 +1533,30 @@ static int resp_read(struct scsi_cmnd * SCpnt, unsigned long long lba,
                 return check_condition_result;
         }
         read_lock_irqsave(&atomic_rw, iflags);
-        if ((lba + num) <= sdebug_store_sectors)
-                ret = fill_from_dev_buffer(SCpnt,
-                                           fake_storep + (lba * SECT_SIZE),
-                                           num * SECT_SIZE);
-        else {
-                /* modulo when one arg is 64 bits needs do_div() */
-                u = lba;
-                block = do_div(u, sdebug_store_sectors);
-                from_bottom = 0;
-                if ((block + num) > sdebug_store_sectors)
-                        from_bottom = (block + num) - sdebug_store_sectors;
-                ret = fill_from_dev_buffer(SCpnt,
-                                           fake_storep + (block * SECT_SIZE),
-                                           (num - from_bottom) * SECT_SIZE);
-                if ((0 == ret) && (from_bottom > 0))
-                        ret = fill_from_dev_buffer(SCpnt, fake_storep,
-                                                   from_bottom * SECT_SIZE);
-        }
+        ret = do_device_access(SCpnt, devip, lba, num, 0);
         read_unlock_irqrestore(&atomic_rw, iflags);
         return ret;
 }
 
-static int resp_write(struct scsi_cmnd * SCpnt, unsigned long long lba,
-                      unsigned int num, struct sdebug_dev_info * devip)
+static int resp_write(struct scsi_cmnd *SCpnt, unsigned long long lba,
+                      unsigned int num, struct sdebug_dev_info *devip)
 {
         unsigned long iflags;
-        unsigned int block, to_bottom;
-        unsigned long long u;
-        int res;
+        int ret;
 
-        if (lba + num > sdebug_capacity) {
-                mk_sense_buffer(devip, ILLEGAL_REQUEST, ADDR_OUT_OF_RANGE,
-                                0);
-                return check_condition_result;
-        }
-        /* transfer length excessive (tie in to block limits VPD page) */
-        if (num > sdebug_store_sectors) {
-                mk_sense_buffer(devip, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
-                                0);
-                return check_condition_result;
-        }
+        ret = check_device_access_params(devip, lba, num);
+        if (ret)
+                return ret;
 
         write_lock_irqsave(&atomic_rw, iflags);
-        if ((lba + num) <= sdebug_store_sectors)
-                res = fetch_to_dev_buffer(SCpnt,
-                                          fake_storep + (lba * SECT_SIZE),
-                                          num * SECT_SIZE);
-        else {
-                /* modulo when one arg is 64 bits needs do_div() */
-                u = lba;
-                block = do_div(u, sdebug_store_sectors);
-                to_bottom = 0;
-                if ((block + num) > sdebug_store_sectors)
-                        to_bottom = (block + num) - sdebug_store_sectors;
-                res = fetch_to_dev_buffer(SCpnt,
-                                          fake_storep + (block * SECT_SIZE),
-                                          (num - to_bottom) * SECT_SIZE);
-                if ((0 == res) && (to_bottom > 0))
-                        res = fetch_to_dev_buffer(SCpnt, fake_storep,
-                                                  to_bottom * SECT_SIZE);
-        }
+        ret = do_device_access(SCpnt, devip, lba, num, 1);
         write_unlock_irqrestore(&atomic_rw, iflags);
-        if (-1 == res)
+        if (-1 == ret)
                 return (DID_ERROR << 16);
-        else if ((res < (num * SECT_SIZE)) &&
+        else if ((ret < (num * SECT_SIZE)) &&
                  (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts))
                 printk(KERN_INFO "scsi_debug: write: cdb indicated=%u, "
-                       " IO sent=%d bytes\n", num * SECT_SIZE, res);
+                       " IO sent=%d bytes\n", num * SECT_SIZE, ret);
         return 0;
 }