[SCSI] scsi_debug: fix logical block provisioning support
provisioning map (map_storep) is a bitmap accessed by bitops.
So the allocation size should be a multiple of sizeof(unsigned long) and
also the bitmap should be cleared by using bitmap_clear() instead of
memset().
Otherwise it will cause problem on big-endian architecture if the number of
bits is not a multiple of BITS_PER_LONG.
I tried testing the logical block provisioning support in scsi_debug,
but it didn't work as I expected.
For example, load scsi_debug module with UNMAP command supported
and fill the storage with random data.
# modprobe scsi_debug lbpu=1
# dd if=/dev/urandom of=/dev/sdb
Then, try to unmap LBA 0, but Get LBA status reports:
# sg_unmap --lba=0 --num=1 /dev/sdb
# sg_get_lba_status --lba=0 /dev/sdb
descriptor LBA: 0x0000000000000000 blocks: 16384 mapped
This is unexpected result. Because UNMAP command to LBA 0 finished
without any errors, but Get LBA status shows that LBA 0 is still mapped.
This problem is due to the wrong translation between LBA and index of
provisioning map. Fix it by using correct translation functions.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 4b5d388..154d987 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1997,24 +1997,39 @@
return ret;
}
+static unsigned long lba_to_map_index(sector_t lba)
+{
+ if (scsi_debug_unmap_alignment) {
+ lba += scsi_debug_unmap_granularity -
+ scsi_debug_unmap_alignment;
+ }
+ do_div(lba, scsi_debug_unmap_granularity);
+
+ return lba;
+}
+
+static sector_t map_index_to_lba(unsigned long index)
+{
+ return index * scsi_debug_unmap_granularity -
+ scsi_debug_unmap_alignment;
+}
+
static unsigned int map_state(sector_t lba, unsigned int *num)
{
- unsigned int granularity, alignment, mapped;
- sector_t block, next, end;
+ sector_t end;
+ unsigned int mapped;
+ unsigned long index;
+ unsigned long next;
- granularity = scsi_debug_unmap_granularity;
- alignment = granularity - scsi_debug_unmap_alignment;
- block = lba + alignment;
- do_div(block, granularity);
-
- mapped = test_bit(block, map_storep);
+ index = lba_to_map_index(lba);
+ mapped = test_bit(index, map_storep);
if (mapped)
- next = find_next_zero_bit(map_storep, map_size, block);
+ next = find_next_zero_bit(map_storep, map_size, index);
else
- next = find_next_bit(map_storep, map_size, block);
+ next = find_next_bit(map_storep, map_size, index);
- end = next * granularity - scsi_debug_unmap_alignment;
+ end = min_t(sector_t, sdebug_store_sectors, map_index_to_lba(next));
*num = end - lba;
return mapped;
@@ -2022,48 +2037,37 @@
static void map_region(sector_t lba, unsigned int len)
{
- unsigned int granularity, alignment;
sector_t end = lba + len;
- granularity = scsi_debug_unmap_granularity;
- alignment = granularity - scsi_debug_unmap_alignment;
-
while (lba < end) {
- sector_t block, rem;
+ unsigned long index = lba_to_map_index(lba);
- block = lba + alignment;
- rem = do_div(block, granularity);
+ if (index < map_size)
+ set_bit(index, map_storep);
- if (block < map_size)
- set_bit(block, map_storep);
-
- lba += granularity - rem;
+ lba = map_index_to_lba(index + 1);
}
}
static void unmap_region(sector_t lba, unsigned int len)
{
- unsigned int granularity, alignment;
sector_t end = lba + len;
- granularity = scsi_debug_unmap_granularity;
- alignment = granularity - scsi_debug_unmap_alignment;
-
while (lba < end) {
- sector_t block, rem;
+ unsigned long index = lba_to_map_index(lba);
- block = lba + alignment;
- rem = do_div(block, granularity);
-
- if (rem == 0 && lba + granularity < end && block < map_size) {
- clear_bit(block, map_storep);
- if (scsi_debug_lbprz)
+ if (lba == map_index_to_lba(index) &&
+ lba + scsi_debug_unmap_granularity <= end &&
+ index < map_size) {
+ clear_bit(index, map_storep);
+ if (scsi_debug_lbprz) {
memset(fake_storep +
lba * scsi_debug_sector_size, 0,
scsi_debug_sector_size *
scsi_debug_unmap_granularity);
+ }
}
- lba += granularity - rem;
+ lba = map_index_to_lba(index + 1);
}
}
@@ -3402,8 +3406,6 @@
/* Logical Block Provisioning */
if (scsi_debug_lbp()) {
- unsigned int map_bytes;
-
scsi_debug_unmap_max_blocks =
clamp(scsi_debug_unmap_max_blocks, 0U, 0xffffffffU);
@@ -3422,9 +3424,8 @@
return -EINVAL;
}
- map_size = (sdebug_store_sectors / scsi_debug_unmap_granularity);
- map_bytes = map_size >> 3;
- map_storep = vmalloc(map_bytes);
+ map_size = lba_to_map_index(sdebug_store_sectors - 1) + 1;
+ map_storep = vmalloc(BITS_TO_LONGS(map_size) * sizeof(long));
printk(KERN_INFO "scsi_debug_init: %lu provisioning blocks\n",
map_size);
@@ -3435,7 +3436,7 @@
goto free_vm;
}
- memset(map_storep, 0x0, map_bytes);
+ bitmap_zero(map_storep, map_size);
/* Map first 1KB for partition table */
if (scsi_debug_num_parts)