Commit b90ebc3d authored by Akinobu Mita's avatar Akinobu Mita Committed by James Bottomley
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[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: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent cc34a8e6

drivers/scsi/scsi_debug.c

+41 −40
Original line number Diff line number Diff line
@@ -1997,24 +1997,39 @@ out: 
	return ret;

}



static unsigned int map_state(sector_t lba, unsigned int *num)

static unsigned long lba_to_map_index(sector_t lba)

{

	unsigned int granularity, alignment, mapped;

	sector_t block, next, end;

	if (scsi_debug_unmap_alignment) {

		lba += scsi_debug_unmap_granularity -

			scsi_debug_unmap_alignment;

	}

	do_div(lba, scsi_debug_unmap_granularity);



	granularity = scsi_debug_unmap_granularity;

	alignment = granularity - scsi_debug_unmap_alignment;

	block = lba + alignment;

	do_div(block, granularity);

	return lba;

}



	mapped = test_bit(block, map_storep);

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)

{

	sector_t end;

	unsigned int mapped;

	unsigned long index;

	unsigned long next;



	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 unsigned int map_state(sector_t lba, unsigned int *num) 


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 @@ static int __init scsi_debug_init(void) 


	/* 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 @@ static int __init scsi_debug_init(void) 
			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 @@ static int __init scsi_debug_init(void) 
			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)

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