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Commit fc3fc352 authored by Akinobu Mita's avatar Akinobu Mita Committed by James Bottomley
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[SCSI] scsi_debug: fix incorrectly nested kmap_atomic() 



In the function prot_verify_write(), kmap_atomic()/kunmap_atomic() for
data page and kmap_atomic()/kunmap_atomic() for protection information
page are not nested each other.

It worked perfectly before commit 3e4d3af5
("mm: stack based kmap_atomic()").  Because the kmap_atomic slot KM_IRQ0
was used for data page and the slot KM_IRQ1 was used for protection page.

But KM_types are gone and kmap_atomic() is using stack based implementation.
So two different kmap_atomic() usages must be strictly nested now.

This change ensures kmap_atomic() usage is strictly nested.

Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Acked-by: default avatar"Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 518d9df8

drivers/scsi/scsi_debug.c

+3 −4
Original line number Diff line number Diff line
@@ -1891,12 +1891,12 @@ static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec, 
	BUG_ON(scsi_sg_count(SCpnt) == 0);

	BUG_ON(scsi_prot_sg_count(SCpnt) == 0);



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

	ppage_offset = 0;



	/* For each data page */

	scsi_for_each_sg(SCpnt, dsgl, scsi_sg_count(SCpnt), i) {

		daddr = kmap_atomic(sg_page(dsgl)) + dsgl->offset;

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



		/* For each sector-sized chunk in data page */

		for (j = 0; j < dsgl->length; j += scsi_debug_sector_size) {
@@ -1980,19 +1980,18 @@ static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec, 
			ppage_offset += sizeof(struct sd_dif_tuple);

		}



		kunmap_atomic(paddr);

		kunmap_atomic(daddr);

	}



	kunmap_atomic(paddr);



	dix_writes++;



	return 0;



out:

	dif_errors++;

	kunmap_atomic(daddr);

	kunmap_atomic(paddr);

	kunmap_atomic(daddr);

	return ret;

}