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Commit 65f72f2a authored by Akinobu Mita's avatar Akinobu Mita Committed by James Bottomley
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[SCSI] scsi_debug: avoid partial copying PI from prot_sglist to dif_storep 



If data integrity support is enabled, prot_verify_write() is called in
response to WRITE commands and it verifies protection info from
prot_sglist by comparing against data sglist, and copies protection info
to dif_storep.

When multiple blocks are transfered by a WRITE command, it verifies and
copies these blocks one by one.  So if it fails to verify protection
info in the middle of blocks, the actual data transfer to fake_storep
isn't proceeded at all although protection info for some blocks are
already copied to dif_storep.  Therefore, it breaks the data integrity
between fake_storep and dif_storep.

This fixes it by ensuring that copying protection info to dif_storep is
done after all blocks are successfully verified.  Reusing dif_copy_prot()
with supporting the opposite direction simplifies this fix.

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 bb8c063c

drivers/scsi/scsi_debug.c

+17 −23
Original line number Diff line number Diff line
@@ -1790,7 +1790,7 @@ static int dif_verify(struct sd_dif_tuple *sdt, const void *data, 
}



static void dif_copy_prot(struct scsi_cmnd *SCpnt, sector_t sector,

			  unsigned int sectors)

			  unsigned int sectors, bool read)

{

	unsigned int i, resid;

	struct scatterlist *psgl;
@@ -1809,10 +1809,18 @@ static void dif_copy_prot(struct scsi_cmnd *SCpnt, sector_t sector, 
			rest = start + len - dif_store_end;



		paddr = kmap_atomic(sg_page(psgl)) + psgl->offset;



		if (read)

			memcpy(paddr, start, len - rest);

		else

			memcpy(start, paddr, len - rest);



		if (rest)

		if (rest) {

			if (read)

				memcpy(paddr + len - rest, dif_storep, rest);

			else

				memcpy(dif_storep, paddr + len - rest, rest);

		}



		sector += len / sizeof(*dif_storep);

		resid -= len;
@@ -1845,7 +1853,7 @@ static int prot_verify_read(struct scsi_cmnd *SCpnt, sector_t start_sec, 
		ei_lba++;

	}



	dif_copy_prot(SCpnt, start_sec, sectors);

	dif_copy_prot(SCpnt, start_sec, sectors, true);

	dix_reads++;



	return 0;
@@ -1928,15 +1936,12 @@ static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec, 
{

	int i, j, ret;

	struct sd_dif_tuple *sdt;

	struct scatterlist *dsgl = scsi_sglist(SCpnt);

	struct scatterlist *dsgl;

	struct scatterlist *psgl = scsi_prot_sglist(SCpnt);

	void *daddr, *paddr;

	sector_t tmp_sec = start_sec;

	sector_t sector;

	sector_t sector = start_sec;

	int ppage_offset;



	sector = do_div(tmp_sec, sdebug_store_sectors);



	BUG_ON(scsi_sg_count(SCpnt) == 0);

	BUG_ON(scsi_prot_sg_count(SCpnt) == 0);
@@ -1964,25 +1969,13 @@ static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec, 


			sdt = paddr + ppage_offset;



			ret = dif_verify(sdt, daddr + j, start_sec, ei_lba);

			ret = dif_verify(sdt, daddr + j, sector, ei_lba);

			if (ret) {

				dump_sector(daddr + j, scsi_debug_sector_size);

				goto out;

			}



			/* Would be great to copy this in bigger

			 * chunks.  However, for the sake of

			 * correctness we need to verify each sector

			 * before writing it to "stable" storage

			 */

			memcpy(dif_storep + sector, sdt, sizeof(*sdt));



			sector++;



			if (sector == sdebug_store_sectors)

				sector = 0;	/* Force wrap */



			start_sec++;

			ei_lba++;

			ppage_offset += sizeof(struct sd_dif_tuple);

		}
@@ -1991,6 +1984,7 @@ static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec, 
		kunmap_atomic(daddr);

	}



	dif_copy_prot(SCpnt, start_sec, sectors, false);

	dix_writes++;



	return 0;