[S390] dcssblk: add >2G DCSSs support and stacked contiguous DCSSs support.
authorHongjie Yang <hongjie@us.ibm.com>
Fri, 10 Oct 2008 19:33:21 +0000 (21:33 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Fri, 10 Oct 2008 19:33:57 +0000 (21:33 +0200)
The DCSS block device driver is modified to add >2G DCSSs support and
allow a DCSS block device to map to a set of contiguous DCSSs.  The
extmem code is also modified to use new Diagnose x'64' subcodes for
>2G DCSSs.

Signed-off-by: Hongjie Yang <hongjie@us.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/mm/extmem.c
drivers/s390/block/dcssblk.c

index f231f5ec74b633555decc0827a8d14d3ceba3d6d..580fc64cc735f343f2576baaba0bebb8eef2b3e9 100644 (file)
 #define DCSS_FINDSEG    0x0c
 #define DCSS_LOADNOLY   0x10
 #define DCSS_SEGEXT     0x18
+#define DCSS_LOADSHRX  0x20
+#define DCSS_LOADNSRX  0x24
+#define DCSS_FINDSEGX  0x2c
+#define DCSS_SEGEXTX   0x38
 #define DCSS_FINDSEGA   0x0c
 
 struct qrange {
-       unsigned int  start; // 3byte start address, 1 byte type
-       unsigned int  end;   // 3byte end address, 1 byte reserved
+       unsigned long  start; /* last byte type */
+       unsigned long  end;   /* last byte reserved */
 };
 
 struct qout64 {
+       unsigned long segstart;
+       unsigned long segend;
+       int segcnt;
+       int segrcnt;
+       struct qrange range[6];
+};
+
+#ifdef CONFIG_64BIT
+struct qrange_old {
+       unsigned int start; /* last byte type */
+       unsigned int end;   /* last byte reserved */
+};
+
+/* output area format for the Diag x'64' old subcode x'18' */
+struct qout64_old {
        int segstart;
        int segend;
        int segcnt;
        int segrcnt;
-       struct qrange range[6];
+       struct qrange_old range[6];
 };
+#endif
 
 struct qin64 {
        char qopcode;
@@ -86,6 +106,55 @@ static DEFINE_MUTEX(dcss_lock);
 static LIST_HEAD(dcss_list);
 static char *segtype_string[] = { "SW", "EW", "SR", "ER", "SN", "EN", "SC",
                                        "EW/EN-MIXED" };
+static int loadshr_scode, loadnsr_scode, findseg_scode;
+static int segext_scode, purgeseg_scode;
+static int scode_set;
+
+/* set correct Diag x'64' subcodes. */
+static int
+dcss_set_subcodes(void)
+{
+#ifdef CONFIG_64BIT
+       char *name = kmalloc(8 * sizeof(char), GFP_DMA);
+       unsigned long rx, ry;
+       int rc;
+
+       if (name == NULL)
+               return -ENOMEM;
+
+       rx = (unsigned long) name;
+       ry = DCSS_FINDSEGX;
+
+       strcpy(name, "dummy");
+       asm volatile(
+               "       diag    %0,%1,0x64\n"
+               "0:     ipm     %2\n"
+               "       srl     %2,28\n"
+               "       j       2f\n"
+               "1:     la      %2,3\n"
+               "2:\n"
+               EX_TABLE(0b, 1b)
+               : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
+
+       kfree(name);
+       /* Diag x'64' new subcodes are supported, set to new subcodes */
+       if (rc != 3) {
+               loadshr_scode = DCSS_LOADSHRX;
+               loadnsr_scode = DCSS_LOADNSRX;
+               purgeseg_scode = DCSS_PURGESEG;
+               findseg_scode = DCSS_FINDSEGX;
+               segext_scode = DCSS_SEGEXTX;
+               return 0;
+       }
+#endif
+       /* Diag x'64' new subcodes are not supported, set to old subcodes */
+       loadshr_scode = DCSS_LOADNOLY;
+       loadnsr_scode = DCSS_LOADNSR;
+       purgeseg_scode = DCSS_PURGESEG;
+       findseg_scode = DCSS_FINDSEG;
+       segext_scode = DCSS_SEGEXT;
+       return 0;
+}
 
 /*
  * Create the 8 bytes, ebcdic VM segment name from
@@ -135,25 +204,45 @@ segment_by_name (char *name)
  * Perform a function on a dcss segment.
  */
 static inline int
-dcss_diag (__u8 func, void *parameter,
+dcss_diag(int *func, void *parameter,
            unsigned long *ret1, unsigned long *ret2)
 {
        unsigned long rx, ry;
        int rc;
 
+       if (scode_set == 0) {
+               rc = dcss_set_subcodes();
+               if (rc < 0)
+                       return rc;
+               scode_set = 1;
+       }
        rx = (unsigned long) parameter;
-       ry = (unsigned long) func;
-       asm volatile(
+       ry = (unsigned long) *func;
+
 #ifdef CONFIG_64BIT
-               "       sam31\n"
-               "       diag    %0,%1,0x64\n"
-               "       sam64\n"
+       /* 64-bit Diag x'64' new subcode, keep in 64-bit addressing mode */
+       if (*func > DCSS_SEGEXT)
+               asm volatile(
+                       "       diag    %0,%1,0x64\n"
+                       "       ipm     %2\n"
+                       "       srl     %2,28\n"
+                       : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
+       /* 31-bit Diag x'64' old subcode, switch to 31-bit addressing mode */
+       else
+               asm volatile(
+                       "       sam31\n"
+                       "       diag    %0,%1,0x64\n"
+                       "       sam64\n"
+                       "       ipm     %2\n"
+                       "       srl     %2,28\n"
+                       : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
 #else
+       asm volatile(
                "       diag    %0,%1,0x64\n"
-#endif
                "       ipm     %2\n"
                "       srl     %2,28\n"
                : "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
+#endif
        *ret1 = rx;
        *ret2 = ry;
        return rc;
@@ -190,14 +279,45 @@ query_segment_type (struct dcss_segment *seg)
        qin->qoutlen = sizeof(struct qout64);
        memcpy (qin->qname, seg->dcss_name, 8);
 
-       diag_cc = dcss_diag (DCSS_SEGEXT, qin, &dummy, &vmrc);
+       diag_cc = dcss_diag(&segext_scode, qin, &dummy, &vmrc);
 
+       if (diag_cc < 0) {
+               rc = diag_cc;
+               goto out_free;
+       }
        if (diag_cc > 1) {
                PRINT_WARN ("segment_type: diag returned error %ld\n", vmrc);
                rc = dcss_diag_translate_rc (vmrc);
                goto out_free;
        }
 
+#ifdef CONFIG_64BIT
+       /* Only old format of output area of Diagnose x'64' is supported,
+          copy data for the new format. */
+       if (segext_scode == DCSS_SEGEXT) {
+               struct qout64_old *qout_old;
+               qout_old = kzalloc(sizeof(struct qout64_old), GFP_DMA);
+               if (qout_old == NULL) {
+                       rc = -ENOMEM;
+                       goto out_free;
+               }
+               memcpy(qout_old, qout, sizeof(struct qout64_old));
+               qout->segstart = (unsigned long) qout_old->segstart;
+               qout->segend = (unsigned long) qout_old->segend;
+               qout->segcnt = qout_old->segcnt;
+               qout->segrcnt = qout_old->segrcnt;
+
+               if (qout->segcnt > 6)
+                       qout->segrcnt = 6;
+               for (i = 0; i < qout->segrcnt; i++) {
+                       qout->range[i].start =
+                               (unsigned long) qout_old->range[i].start;
+                       qout->range[i].end =
+                               (unsigned long) qout_old->range[i].end;
+               }
+               kfree(qout_old);
+       }
+#endif
        if (qout->segcnt > 6) {
                rc = -ENOTSUPP;
                goto out_free;
@@ -268,6 +388,30 @@ segment_type (char* name)
        return seg.vm_segtype;
 }
 
+/*
+ * check if segment collides with other segments that are currently loaded
+ * returns 1 if this is the case, 0 if no collision was found
+ */
+static int
+segment_overlaps_others (struct dcss_segment *seg)
+{
+       struct list_head *l;
+       struct dcss_segment *tmp;
+
+       BUG_ON(!mutex_is_locked(&dcss_lock));
+       list_for_each(l, &dcss_list) {
+               tmp = list_entry(l, struct dcss_segment, list);
+               if ((tmp->start_addr >> 20) > (seg->end >> 20))
+                       continue;
+               if ((tmp->end >> 20) < (seg->start_addr >> 20))
+                       continue;
+               if (seg == tmp)
+                       continue;
+               return 1;
+       }
+       return 0;
+}
+
 /*
  * real segment loading function, called from segment_load
  */
@@ -276,7 +420,8 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
 {
        struct dcss_segment *seg = kmalloc(sizeof(struct dcss_segment),
                        GFP_DMA);
-       int dcss_command, rc, diag_cc;
+       int rc, diag_cc;
+       unsigned long start_addr, end_addr, dummy;
 
        if (seg == NULL) {
                rc = -ENOMEM;
@@ -287,6 +432,13 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
        if (rc < 0)
                goto out_free;
 
+       if (loadshr_scode == DCSS_LOADSHRX) {
+               if (segment_overlaps_others(seg)) {
+                       rc = -EBUSY;
+                       goto out_free;
+               }
+       }
+
        rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
 
        if (rc)
@@ -316,20 +468,28 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
        }
 
        if (do_nonshared)
-               dcss_command = DCSS_LOADNSR;
+               diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
+                               &start_addr, &end_addr);
        else
-               dcss_command = DCSS_LOADNOLY;
-
-       diag_cc = dcss_diag(dcss_command, seg->dcss_name,
-                       &seg->start_addr, &seg->end);
+               diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
+                               &start_addr, &end_addr);
+       if (diag_cc < 0) {
+               dcss_diag(&purgeseg_scode, seg->dcss_name,
+                               &dummy, &dummy);
+               rc = diag_cc;
+               goto out_resource;
+       }
        if (diag_cc > 1) {
                PRINT_WARN ("segment_load: could not load segment %s - "
-                               "diag returned error (%ld)\n",name,seg->end);
-               rc = dcss_diag_translate_rc (seg->end);
-               dcss_diag(DCSS_PURGESEG, seg->dcss_name,
-                               &seg->start_addr, &seg->end);
+                               "diag returned error (%ld)\n",
+                               name, end_addr);
+               rc = dcss_diag_translate_rc(end_addr);
+               dcss_diag(&purgeseg_scode, seg->dcss_name,
+                               &dummy, &dummy);
                goto out_resource;
        }
+       seg->start_addr = start_addr;
+       seg->end = end_addr;
        seg->do_nonshared = do_nonshared;
        atomic_set(&seg->ref_count, 1);
        list_add(&seg->list, &dcss_list);
@@ -423,8 +583,8 @@ int
 segment_modify_shared (char *name, int do_nonshared)
 {
        struct dcss_segment *seg;
-       unsigned long dummy;
-       int dcss_command, rc, diag_cc;
+       unsigned long start_addr, end_addr, dummy;
+       int rc, diag_cc;
 
        mutex_lock(&dcss_lock);
        seg = segment_by_name (name);
@@ -445,38 +605,51 @@ segment_modify_shared (char *name, int do_nonshared)
                goto out_unlock;
        }
        release_resource(seg->res);
-       if (do_nonshared) {
-               dcss_command = DCSS_LOADNSR;
+       if (do_nonshared)
                seg->res->flags &= ~IORESOURCE_READONLY;
-       } else {
-               dcss_command = DCSS_LOADNOLY;
+       else
                if (seg->vm_segtype == SEG_TYPE_SR ||
                    seg->vm_segtype == SEG_TYPE_ER)
                        seg->res->flags |= IORESOURCE_READONLY;
-       }
+
        if (request_resource(&iomem_resource, seg->res)) {
                PRINT_WARN("segment_modify_shared: could not reload segment %s"
                           " - overlapping resources\n", name);
                rc = -EBUSY;
                kfree(seg->res);
-               goto out_del;
+               goto out_del_mem;
+       }
+
+       dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
+       if (do_nonshared)
+               diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
+                               &start_addr, &end_addr);
+       else
+               diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
+                               &start_addr, &end_addr);
+       if (diag_cc < 0) {
+               rc = diag_cc;
+               goto out_del_res;
        }
-       dcss_diag(DCSS_PURGESEG, seg->dcss_name, &dummy, &dummy);
-       diag_cc = dcss_diag(dcss_command, seg->dcss_name,
-                       &seg->start_addr, &seg->end);
        if (diag_cc > 1) {
                PRINT_WARN ("segment_modify_shared: could not reload segment %s"
-                               " - diag returned error (%ld)\n",name,seg->end);
-               rc = dcss_diag_translate_rc (seg->end);
-               goto out_del;
+                               " - diag returned error (%ld)\n",
+                               name, end_addr);
+               rc = dcss_diag_translate_rc(end_addr);
+               goto out_del_res;
        }
+       seg->start_addr = start_addr;
+       seg->end = end_addr;
        seg->do_nonshared = do_nonshared;
        rc = 0;
        goto out_unlock;
- out_del:
+ out_del_res:
+       release_resource(seg->res);
+       kfree(seg->res);
+ out_del_mem:
        vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
        list_del(&seg->list);
-       dcss_diag(DCSS_PURGESEG, seg->dcss_name, &dummy, &dummy);
+       dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
        kfree(seg);
  out_unlock:
        mutex_unlock(&dcss_lock);
@@ -510,7 +683,7 @@ segment_unload(char *name)
        kfree(seg->res);
        vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
        list_del(&seg->list);
-       dcss_diag(DCSS_PURGESEG, seg->dcss_name, &dummy, &dummy);
+       dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
        kfree(seg);
 out_unlock:
        mutex_unlock(&dcss_lock);
@@ -545,7 +718,7 @@ segment_save(char *name)
        endpfn = (seg->end) >> PAGE_SHIFT;
        sprintf(cmd1, "DEFSEG %s", name);
        for (i=0; i<seg->segcnt; i++) {
-               sprintf(cmd1+strlen(cmd1), " %X-%X %s",
+               sprintf(cmd1+strlen(cmd1), " %lX-%lX %s",
                        seg->range[i].start >> PAGE_SHIFT,
                        seg->range[i].end >> PAGE_SHIFT,
                        segtype_string[seg->range[i].start & 0xff]);
index ea4272c8c677813be816604662b82f751253ffca..a7ff167d5b81089c781a3f3c9aa9e736cc8da48e 100644 (file)
@@ -31,7 +31,6 @@
 #define PRINT_WARN(x...)  printk(KERN_WARNING DCSSBLK_NAME " warning: " x)
 #define PRINT_ERR(x...)          printk(KERN_ERR DCSSBLK_NAME " error: " x)
 
-
 static int dcssblk_open(struct inode *inode, struct file *filp);
 static int dcssblk_release(struct inode *inode, struct file *filp);
 static int dcssblk_make_request(struct request_queue *q, struct bio *bio);
@@ -48,6 +47,30 @@ static struct block_device_operations dcssblk_devops = {
        .direct_access  = dcssblk_direct_access,
 };
 
+struct dcssblk_dev_info {
+       struct list_head lh;
+       struct device dev;
+       char segment_name[BUS_ID_SIZE];
+       atomic_t use_count;
+       struct gendisk *gd;
+       unsigned long start;
+       unsigned long end;
+       int segment_type;
+       unsigned char save_pending;
+       unsigned char is_shared;
+       struct request_queue *dcssblk_queue;
+       int num_of_segments;
+       struct list_head seg_list;
+};
+
+struct segment_info {
+       struct list_head lh;
+       char segment_name[BUS_ID_SIZE];
+       unsigned long start;
+       unsigned long end;
+       int segment_type;
+};
+
 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
                                  size_t count);
 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
@@ -58,30 +81,20 @@ static ssize_t dcssblk_save_show(struct device *dev, struct device_attribute *at
 static ssize_t dcssblk_shared_store(struct device * dev, struct device_attribute *attr, const char * buf,
                                  size_t count);
 static ssize_t dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf);
+static ssize_t dcssblk_seglist_show(struct device *dev,
+                               struct device_attribute *attr,
+                               char *buf);
 
 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
-static DEVICE_ATTR(save, S_IWUSR | S_IRUGO, dcssblk_save_show,
+static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
                   dcssblk_save_store);
-static DEVICE_ATTR(shared, S_IWUSR | S_IRUGO, dcssblk_shared_show,
+static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
                   dcssblk_shared_store);
+static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);
 
 static struct device *dcssblk_root_dev;
 
-struct dcssblk_dev_info {
-       struct list_head lh;
-       struct device dev;
-       char segment_name[BUS_ID_SIZE];
-       atomic_t use_count;
-       struct gendisk *gd;
-       unsigned long start;
-       unsigned long end;
-       int segment_type;
-       unsigned char save_pending;
-       unsigned char is_shared;
-       struct request_queue *dcssblk_queue;
-};
-
 static LIST_HEAD(dcssblk_devices);
 static struct rw_semaphore dcssblk_devices_sem;
 
@@ -91,8 +104,15 @@ static struct rw_semaphore dcssblk_devices_sem;
 static void
 dcssblk_release_segment(struct device *dev)
 {
-       PRINT_DEBUG("segment release fn called for %s\n", dev_name(dev));
-       kfree(container_of(dev, struct dcssblk_dev_info, dev));
+       struct dcssblk_dev_info *dev_info;
+       struct segment_info *entry, *temp;
+
+       dev_info = container_of(dev, struct dcssblk_dev_info, dev);
+       list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) {
+               list_del(&entry->lh);
+               kfree(entry);
+       }
+       kfree(dev_info);
        module_put(THIS_MODULE);
 }
 
@@ -142,6 +162,169 @@ dcssblk_get_device_by_name(char *name)
        return NULL;
 }
 
+/*
+ * get the struct segment_info from seg_list
+ * for the given name.
+ * down_read(&dcssblk_devices_sem) must be held.
+ */
+static struct segment_info *
+dcssblk_get_segment_by_name(char *name)
+{
+       struct dcssblk_dev_info *dev_info;
+       struct segment_info *entry;
+
+       list_for_each_entry(dev_info, &dcssblk_devices, lh) {
+               list_for_each_entry(entry, &dev_info->seg_list, lh) {
+                       if (!strcmp(name, entry->segment_name))
+                               return entry;
+               }
+       }
+       return NULL;
+}
+
+/*
+ * get the highest address of the multi-segment block.
+ */
+static unsigned long
+dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info)
+{
+       unsigned long highest_addr;
+       struct segment_info *entry;
+
+       highest_addr = 0;
+       list_for_each_entry(entry, &dev_info->seg_list, lh) {
+               if (highest_addr < entry->end)
+                       highest_addr = entry->end;
+       }
+       return highest_addr;
+}
+
+/*
+ * get the lowest address of the multi-segment block.
+ */
+static unsigned long
+dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info)
+{
+       int set_first;
+       unsigned long lowest_addr;
+       struct segment_info *entry;
+
+       set_first = 0;
+       lowest_addr = 0;
+       list_for_each_entry(entry, &dev_info->seg_list, lh) {
+               if (set_first == 0) {
+                       lowest_addr = entry->start;
+                       set_first = 1;
+               } else {
+                       if (lowest_addr > entry->start)
+                               lowest_addr = entry->start;
+               }
+       }
+       return lowest_addr;
+}
+
+/*
+ * Check continuity of segments.
+ */
+static int
+dcssblk_is_continuous(struct dcssblk_dev_info *dev_info)
+{
+       int i, j, rc;
+       struct segment_info *sort_list, *entry, temp;
+
+       if (dev_info->num_of_segments <= 1)
+               return 0;
+
+       sort_list = kzalloc(
+                       sizeof(struct segment_info) * dev_info->num_of_segments,
+                       GFP_KERNEL);
+       if (sort_list == NULL)
+               return -ENOMEM;
+       i = 0;
+       list_for_each_entry(entry, &dev_info->seg_list, lh) {
+               memcpy(&sort_list[i], entry, sizeof(struct segment_info));
+               i++;
+       }
+
+       /* sort segments */
+       for (i = 0; i < dev_info->num_of_segments; i++)
+               for (j = 0; j < dev_info->num_of_segments; j++)
+                       if (sort_list[j].start > sort_list[i].start) {
+                               memcpy(&temp, &sort_list[i],
+                                       sizeof(struct segment_info));
+                               memcpy(&sort_list[i], &sort_list[j],
+                                       sizeof(struct segment_info));
+                               memcpy(&sort_list[j], &temp,
+                                       sizeof(struct segment_info));
+                       }
+
+       /* check continuity */
+       for (i = 0; i < dev_info->num_of_segments - 1; i++) {
+               if ((sort_list[i].end + 1) != sort_list[i+1].start) {
+                       PRINT_ERR("Segment %s is not contiguous with "
+                               "segment %s\n",
+                               sort_list[i].segment_name,
+                               sort_list[i+1].segment_name);
+                       rc = -EINVAL;
+                       goto out;
+               }
+               /* EN and EW are allowed in a block device */
+               if (sort_list[i].segment_type != sort_list[i+1].segment_type) {
+                       if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) ||
+                               (sort_list[i].segment_type == SEG_TYPE_ER) ||
+                               !(sort_list[i+1].segment_type &
+                               SEGMENT_EXCLUSIVE) ||
+                               (sort_list[i+1].segment_type == SEG_TYPE_ER)) {
+                               PRINT_ERR("Segment %s has different type from "
+                                       "segment %s\n",
+                                       sort_list[i].segment_name,
+                                       sort_list[i+1].segment_name);
+                               rc = -EINVAL;
+                               goto out;
+                       }
+               }
+       }
+       rc = 0;
+out:
+       kfree(sort_list);
+       return rc;
+}
+
+/*
+ * Load a segment
+ */
+static int
+dcssblk_load_segment(char *name, struct segment_info **seg_info)
+{
+       int rc;
+
+       /* already loaded? */
+       down_read(&dcssblk_devices_sem);
+       *seg_info = dcssblk_get_segment_by_name(name);
+       up_read(&dcssblk_devices_sem);
+       if (*seg_info != NULL)
+               return -EEXIST;
+
+       /* get a struct segment_info */
+       *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL);
+       if (*seg_info == NULL)
+               return -ENOMEM;
+
+       strcpy((*seg_info)->segment_name, name);
+
+       /* load the segment */
+       rc = segment_load(name, SEGMENT_SHARED,
+                       &(*seg_info)->start, &(*seg_info)->end);
+       if (rc < 0) {
+               segment_warning(rc, (*seg_info)->segment_name);
+               kfree(*seg_info);
+       } else {
+               INIT_LIST_HEAD(&(*seg_info)->lh);
+               (*seg_info)->segment_type = rc;
+       }
+       return rc;
+}
+
 static void dcssblk_unregister_callback(struct device *dev)
 {
        device_unregister(dev);
@@ -165,6 +348,7 @@ static ssize_t
 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 {
        struct dcssblk_dev_info *dev_info;
+       struct segment_info *entry, *temp;
        int rc;
 
        if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
@@ -172,46 +356,46 @@ dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const ch
        down_write(&dcssblk_devices_sem);
        dev_info = container_of(dev, struct dcssblk_dev_info, dev);
        if (atomic_read(&dev_info->use_count)) {
-               PRINT_ERR("share: segment %s is busy!\n",
-                         dev_info->segment_name);
                rc = -EBUSY;
                goto out;
        }
        if (inbuf[0] == '1') {
-               // reload segment in shared mode
-               rc = segment_modify_shared(dev_info->segment_name,
-                                          SEGMENT_SHARED);
-               if (rc < 0) {
-                       BUG_ON(rc == -EINVAL);
-                       if (rc != -EAGAIN)
-                               goto removeseg;
-               } else {
-                       dev_info->is_shared = 1;
-                       switch (dev_info->segment_type) {
-                               case SEG_TYPE_SR:
-                               case SEG_TYPE_ER:
-                               case SEG_TYPE_SC:
-                                       set_disk_ro(dev_info->gd,1);
+               /* reload segments in shared mode */
+               list_for_each_entry(entry, &dev_info->seg_list, lh) {
+                       rc = segment_modify_shared(entry->segment_name,
+                                               SEGMENT_SHARED);
+                       if (rc < 0) {
+                               BUG_ON(rc == -EINVAL);
+                               if (rc != -EAGAIN)
+                                       goto removeseg;
                        }
                }
+               dev_info->is_shared = 1;
+               switch (dev_info->segment_type) {
+               case SEG_TYPE_SR:
+               case SEG_TYPE_ER:
+               case SEG_TYPE_SC:
+                       set_disk_ro(dev_info->gd, 1);
+               }
        } else if (inbuf[0] == '0') {
-               // reload segment in exclusive mode
+               /* reload segments in exclusive mode */
                if (dev_info->segment_type == SEG_TYPE_SC) {
                        PRINT_ERR("Segment type SC (%s) cannot be loaded in "
-                                 "non-shared mode\n", dev_info->segment_name);
+                               "non-shared mode\n", dev_info->segment_name);
                        rc = -EINVAL;
                        goto out;
                }
-               rc = segment_modify_shared(dev_info->segment_name,
-                                          SEGMENT_EXCLUSIVE);
-               if (rc < 0) {
-                       BUG_ON(rc == -EINVAL);
-                       if (rc != -EAGAIN)
-                               goto removeseg;
-               } else {
-                       dev_info->is_shared = 0;
-                       set_disk_ro(dev_info->gd, 0);
+               list_for_each_entry(entry, &dev_info->seg_list, lh) {
+                       rc = segment_modify_shared(entry->segment_name,
+                                                  SEGMENT_EXCLUSIVE);
+                       if (rc < 0) {
+                               BUG_ON(rc == -EINVAL);
+                               if (rc != -EAGAIN)
+                                       goto removeseg;
+                       }
                }
+               dev_info->is_shared = 0;
+               set_disk_ro(dev_info->gd, 0);
        } else {
                rc = -EINVAL;
                goto out;
@@ -220,8 +404,14 @@ dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const ch
        goto out;
 
 removeseg:
-       PRINT_ERR("Could not reload segment %s, removing it now!\n",
-                       dev_info->segment_name);
+       PRINT_ERR("Could not reload segment(s) of the device %s, removing "
+               "segment(s) now!\n",
+               dev_info->segment_name);
+       temp = entry;
+       list_for_each_entry(entry, &dev_info->seg_list, lh) {
+               if (entry != temp)
+                       segment_unload(entry->segment_name);
+       }
        list_del(&dev_info->lh);
 
        del_gendisk(dev_info->gd);
@@ -254,6 +444,7 @@ static ssize_t
 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 {
        struct dcssblk_dev_info *dev_info;
+       struct segment_info *entry;
 
        if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
                return -EINVAL;
@@ -263,14 +454,16 @@ dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char
        if (inbuf[0] == '1') {
                if (atomic_read(&dev_info->use_count) == 0) {
                        // device is idle => we save immediately
-                       PRINT_INFO("Saving segment %s\n",
+                       PRINT_INFO("Saving segment(s) of the device %s\n",
                                   dev_info->segment_name);
-                       segment_save(dev_info->segment_name);
+                       list_for_each_entry(entry, &dev_info->seg_list, lh) {
+                               segment_save(entry->segment_name);
+                       }
                }  else {
                        // device is busy => we save it when it becomes
                        // idle in dcssblk_release
-                       PRINT_INFO("Segment %s is currently busy, it will "
-                                  "be saved when it becomes idle...\n",
+                       PRINT_INFO("Device %s is currently busy, segment(s) "
+                                  "will be saved when it becomes idle...\n",
                                   dev_info->segment_name);
                        dev_info->save_pending = 1;
                }
@@ -279,7 +472,8 @@ dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char
                        // device is busy & the user wants to undo his save
                        // request
                        dev_info->save_pending = 0;
-                       PRINT_INFO("Pending save for segment %s deactivated\n",
+                       PRINT_INFO("Pending save for segment(s) of the device "
+                                       "%s deactivated\n",
                                        dev_info->segment_name);
                }
        } else {
@@ -290,67 +484,124 @@ dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char
        return count;
 }
 
+/*
+ * device attribute for showing all segments in a device
+ */
+static ssize_t
+dcssblk_seglist_show(struct device *dev, struct device_attribute *attr,
+               char *buf)
+{
+       int i;
+
+       struct dcssblk_dev_info *dev_info;
+       struct segment_info *entry;
+
+       down_read(&dcssblk_devices_sem);
+       dev_info = container_of(dev, struct dcssblk_dev_info, dev);
+       i = 0;
+       buf[0] = '\0';
+       list_for_each_entry(entry, &dev_info->seg_list, lh) {
+               strcpy(&buf[i], entry->segment_name);
+               i += strlen(entry->segment_name);
+               buf[i] = '\n';
+               i++;
+       }
+       up_read(&dcssblk_devices_sem);
+       return i;
+}
+
 /*
  * device attribute for adding devices
  */
 static ssize_t
 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 {
-       int rc, i;
+       int rc, i, j, num_of_segments;
        struct dcssblk_dev_info *dev_info;
+       struct segment_info *seg_info, *temp;
        char *local_buf;
        unsigned long seg_byte_size;
 
        dev_info = NULL;
+       seg_info = NULL;
        if (dev != dcssblk_root_dev) {
                rc = -EINVAL;
                goto out_nobuf;
        }
+       if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) {
+               rc = -ENAMETOOLONG;
+               goto out_nobuf;
+       }
+
        local_buf = kmalloc(count + 1, GFP_KERNEL);
        if (local_buf == NULL) {
                rc = -ENOMEM;
                goto out_nobuf;
        }
+
        /*
         * parse input
         */
+       num_of_segments = 0;
        for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
-               local_buf[i] = toupper(buf[i]);
+               for (j = i; (buf[j] != ':') &&
+                       (buf[j] != '\0') &&
+                       (buf[j] != '\n') &&
+                       j < count; j++) {
+                       local_buf[j-i] = toupper(buf[j]);
+               }
+               local_buf[j-i] = '\0';
+               if (((j - i) == 0) || ((j - i) > 8)) {
+                       rc = -ENAMETOOLONG;
+                       goto seg_list_del;
+               }
+
+               rc = dcssblk_load_segment(local_buf, &seg_info);
+               if (rc < 0)
+                       goto seg_list_del;
+               /*
+                * get a struct dcssblk_dev_info
+                */
+               if (num_of_segments == 0) {
+                       dev_info = kzalloc(sizeof(struct dcssblk_dev_info),
+                                       GFP_KERNEL);
+                       if (dev_info == NULL) {
+                               rc = -ENOMEM;
+                               goto out;
+                       }
+                       strcpy(dev_info->segment_name, local_buf);
+                       dev_info->segment_type = seg_info->segment_type;
+                       INIT_LIST_HEAD(&dev_info->seg_list);
+               }
+               list_add_tail(&seg_info->lh, &dev_info->seg_list);
+               num_of_segments++;
+               i = j;
+
+               if ((buf[j] == '\0') || (buf[j] == '\n'))
+                       break;
        }
-       local_buf[i] = '\0';
-       if ((i == 0) || (i > 8)) {
+
+       /* no trailing colon at the end of the input */
+       if ((i > 0) && (buf[i-1] == ':')) {
                rc = -ENAMETOOLONG;
-               goto out;
-       }
-       /*
-        * already loaded?
-        */
-       down_read(&dcssblk_devices_sem);
-       dev_info = dcssblk_get_device_by_name(local_buf);
-       up_read(&dcssblk_devices_sem);
-       if (dev_info != NULL) {
-               PRINT_WARN("Segment %s already loaded!\n", local_buf);
-               rc = -EEXIST;
-               goto out;
-       }
-       /*
-        * get a struct dcssblk_dev_info
-        */
-       dev_info = kzalloc(sizeof(struct dcssblk_dev_info), GFP_KERNEL);
-       if (dev_info == NULL) {
-               rc = -ENOMEM;
-               goto out;
+               goto seg_list_del;
        }
+       strlcpy(local_buf, buf, i + 1);
+       dev_info->num_of_segments = num_of_segments;
+       rc = dcssblk_is_continuous(dev_info);
+       if (rc < 0)
+               goto seg_list_del;
+
+       dev_info->start = dcssblk_find_lowest_addr(dev_info);
+       dev_info->end = dcssblk_find_highest_addr(dev_info);
 
-       strcpy(dev_info->segment_name, local_buf);
-       dev_set_name(&dev_info->dev, local_buf);
+       dev_set_name(&dev_info->dev, dev_info->segment_name);
        dev_info->dev.release = dcssblk_release_segment;
        INIT_LIST_HEAD(&dev_info->lh);
-
        dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
        if (dev_info->gd == NULL) {
                rc = -ENOMEM;
-               goto free_dev_info;
+               goto seg_list_del;
        }
        dev_info->gd->major = dcssblk_major;
        dev_info->gd->fops = &dcssblk_devops;
@@ -360,65 +611,52 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
        dev_info->gd->driverfs_dev = &dev_info->dev;
        blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
        blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
-       /*
-        * load the segment
-        */
-       rc = segment_load(local_buf, SEGMENT_SHARED,
-                               &dev_info->start, &dev_info->end);
-       if (rc < 0) {
-               segment_warning(rc, dev_info->segment_name);
-               goto dealloc_gendisk;
-       }
+
        seg_byte_size = (dev_info->end - dev_info->start + 1);
        set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
-       PRINT_INFO("Loaded segment %s, size = %lu Byte, "
+       PRINT_INFO("Loaded segment(s) %s, size = %lu Byte, "
                   "capacity = %lu (512 Byte) sectors\n", local_buf,
                   seg_byte_size, seg_byte_size >> 9);
 
-       dev_info->segment_type = rc;
        dev_info->save_pending = 0;
        dev_info->is_shared = 1;
        dev_info->dev.parent = dcssblk_root_dev;
 
        /*
-        * get minor, add to list
+        *get minor, add to list
         */
        down_write(&dcssblk_devices_sem);
-       if (dcssblk_get_device_by_name(local_buf)) {
-               up_write(&dcssblk_devices_sem);
+       if (dcssblk_get_segment_by_name(local_buf)) {
                rc = -EEXIST;
-               goto unload_seg;
+               goto release_gd;
        }
        rc = dcssblk_assign_free_minor(dev_info);
-       if (rc) {
-               up_write(&dcssblk_devices_sem);
-               PRINT_ERR("No free minor number available! "
-                         "Unloading segment...\n");
-               goto unload_seg;
-       }
+       if (rc)
+               goto release_gd;
        sprintf(dev_info->gd->disk_name, "dcssblk%d",
                MINOR(disk_devt(dev_info->gd)));
        list_add_tail(&dev_info->lh, &dcssblk_devices);
 
        if (!try_module_get(THIS_MODULE)) {
                rc = -ENODEV;
-               goto list_del;
+               goto dev_list_del;
        }
        /*
         * register the device
         */
        rc = device_register(&dev_info->dev);
        if (rc) {
-               PRINT_ERR("Segment %s could not be registered RC=%d\n",
-                               local_buf, rc);
                module_put(THIS_MODULE);
-               goto list_del;
+               goto dev_list_del;
        }
        get_device(&dev_info->dev);
        rc = device_create_file(&dev_info->dev, &dev_attr_shared);
        if (rc)
                goto unregister_dev;
        rc = device_create_file(&dev_info->dev, &dev_attr_save);
+       if (rc)
+               goto unregister_dev;
+       rc = device_create_file(&dev_info->dev, &dev_attr_seglist);
        if (rc)
                goto unregister_dev;
 
@@ -434,7 +672,6 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
                        set_disk_ro(dev_info->gd,0);
                        break;
        }
-       PRINT_DEBUG("Segment %s loaded successfully\n", local_buf);
        up_write(&dcssblk_devices_sem);
        rc = count;
        goto out;
@@ -445,20 +682,27 @@ unregister_dev:
        dev_info->gd->queue = NULL;
        put_disk(dev_info->gd);
        device_unregister(&dev_info->dev);
-       segment_unload(dev_info->segment_name);
+       list_for_each_entry(seg_info, &dev_info->seg_list, lh) {
+               segment_unload(seg_info->segment_name);
+       }
        put_device(&dev_info->dev);
        up_write(&dcssblk_devices_sem);
        goto out;
-list_del:
+dev_list_del:
        list_del(&dev_info->lh);
-       up_write(&dcssblk_devices_sem);
-unload_seg:
-       segment_unload(local_buf);
-dealloc_gendisk:
+release_gd:
        blk_cleanup_queue(dev_info->dcssblk_queue);
        dev_info->gd->queue = NULL;
        put_disk(dev_info->gd);
-free_dev_info:
+       up_write(&dcssblk_devices_sem);
+seg_list_del:
+       if (dev_info == NULL)
+               goto out;
+       list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) {
+               list_del(&seg_info->lh);
+               segment_unload(seg_info->segment_name);
+               kfree(seg_info);
+       }
        kfree(dev_info);
 out:
        kfree(local_buf);
@@ -473,6 +717,7 @@ static ssize_t
 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 {
        struct dcssblk_dev_info *dev_info;
+       struct segment_info *entry;
        int rc, i;
        char *local_buf;
 
@@ -499,26 +744,28 @@ dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const ch
        dev_info = dcssblk_get_device_by_name(local_buf);
        if (dev_info == NULL) {
                up_write(&dcssblk_devices_sem);
-               PRINT_WARN("Segment %s is not loaded!\n", local_buf);
+               PRINT_WARN("Device %s is not loaded!\n", local_buf);
                rc = -ENODEV;
                goto out_buf;
        }
        if (atomic_read(&dev_info->use_count) != 0) {
                up_write(&dcssblk_devices_sem);
-               PRINT_WARN("Segment %s is in use!\n", local_buf);
+               PRINT_WARN("Device %s is in use!\n", local_buf);
                rc = -EBUSY;
                goto out_buf;
        }
-       list_del(&dev_info->lh);
 
+       list_del(&dev_info->lh);
        del_gendisk(dev_info->gd);
        blk_cleanup_queue(dev_info->dcssblk_queue);
        dev_info->gd->queue = NULL;
        put_disk(dev_info->gd);
        device_unregister(&dev_info->dev);
-       segment_unload(dev_info->segment_name);
-       PRINT_DEBUG("Segment %s unloaded successfully\n",
-                       dev_info->segment_name);
+
+       /* unload all related segments */
+       list_for_each_entry(entry, &dev_info->seg_list, lh)
+               segment_unload(entry->segment_name);
+
        put_device(&dev_info->dev);
        up_write(&dcssblk_devices_sem);
 
@@ -550,6 +797,7 @@ static int
 dcssblk_release(struct inode *inode, struct file *filp)
 {
        struct dcssblk_dev_info *dev_info;
+       struct segment_info *entry;
        int rc;
 
        dev_info = inode->i_bdev->bd_disk->private_data;
@@ -560,9 +808,11 @@ dcssblk_release(struct inode *inode, struct file *filp)
        down_write(&dcssblk_devices_sem);
        if (atomic_dec_and_test(&dev_info->use_count)
            && (dev_info->save_pending)) {
-               PRINT_INFO("Segment %s became idle and is being saved now\n",
+               PRINT_INFO("Device %s became idle and is being saved now\n",
                            dev_info->segment_name);
-               segment_save(dev_info->segment_name);
+               list_for_each_entry(entry, &dev_info->seg_list, lh) {
+                       segment_save(entry->segment_name);
+               }
                dev_info->save_pending = 0;
        }
        up_write(&dcssblk_devices_sem);
@@ -602,7 +852,7 @@ dcssblk_make_request(struct request_queue *q, struct bio *bio)
                case SEG_TYPE_SC:
                        /* cannot write to these segments */
                        if (bio_data_dir(bio) == WRITE) {
-                               PRINT_WARN("rejecting write to ro segment %s\n",
+                               PRINT_WARN("rejecting write to ro device %s\n",
                                           dev_name(&dev_info->dev));
                                goto fail;
                        }
@@ -658,7 +908,7 @@ static void
 dcssblk_check_params(void)
 {
        int rc, i, j, k;
-       char buf[9];
+       char buf[DCSSBLK_PARM_LEN + 1];
        struct dcssblk_dev_info *dev_info;
 
        for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
@@ -666,15 +916,16 @@ dcssblk_check_params(void)
                for (j = i; (dcssblk_segments[j] != ',')  &&
                            (dcssblk_segments[j] != '\0') &&
                            (dcssblk_segments[j] != '(')  &&
-                           (j - i) < 8; j++)
+                           (j < DCSSBLK_PARM_LEN); j++)
                {
                        buf[j-i] = dcssblk_segments[j];
                }
                buf[j-i] = '\0';
                rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
                if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
-                       for (k = 0; buf[k] != '\0'; k++)
+                       for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
                                buf[k] = toupper(buf[k]);
+                       buf[k] = '\0';
                        if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
                                down_read(&dcssblk_devices_sem);
                                dev_info = dcssblk_get_device_by_name(buf);
@@ -741,10 +992,12 @@ module_exit(dcssblk_exit);
 
 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
-                "comma-separated list, each name max. 8 chars.\n"
-                "Adding \"(local)\" to segment name equals echoing 0 to "
-                "/sys/devices/dcssblk/<segment name>/shared after loading "
-                "the segment - \n"
-                "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
+                "comma-separated list, names in each set separated "
+                "by commas are separated by colons, each set contains "
+                "names of contiguous segments and each name max. 8 chars.\n"
+                "Adding \"(local)\" to the end of each set equals echoing 0 "
+                "to /sys/devices/dcssblk/<device name>/shared after loading "
+                "the contiguous segments - \n"
+                "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
 
 MODULE_LICENSE("GPL");