Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 41bb4c43 authored by Stuart Hayes's avatar Stuart Hayes Committed by Bartlomiej Zolnierkiewicz
Browse files

[PATCH] ide-scsi: kmap scatter/gather before doing PIO 



From: Stuart Hayes <Stuart_Hayes@dell.com>

The system can panic with a null pointer dereference using ide-scsi if
PIO is being done on scatter gather pages that are in high memory,
because page_address() returns 0.  We are actually seeing this using a
tape drive.  This patch will kmap_atomic() the pages before performing
PIO.

Signed-off-by: default avatarBartlomiej Zolnierkiewicz <bzolnier@elka.pw.edu.pl>
parent 8604affd

drivers/scsi/ide-scsi.c

+24 −4
Original line number Diff line number Diff line
@@ -179,8 +179,18 @@ static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigne 
			return;

		}

		count = min(pc->sg->length - pc->b_count, bcount);

		if (PageHighMem(pc->sg->page)) {

			unsigned long flags;



			local_irq_save(flags);

			buf = kmap_atomic(pc->sg->page, KM_IRQ0) + pc->sg->offset;

			drive->hwif->atapi_input_bytes(drive, buf + pc->b_count, count);

			kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);

			local_irq_restore(flags);

		} else {

			buf = page_address(pc->sg->page) + pc->sg->offset;

			drive->hwif->atapi_input_bytes(drive, buf + pc->b_count, count);

		}

		bcount -= count; pc->b_count += count;

		if (pc->b_count == pc->sg->length) {

			pc->sg++;
@@ -201,8 +211,18 @@ static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsign 
			return;

		}

		count = min(pc->sg->length - pc->b_count, bcount);

		if (PageHighMem(pc->sg->page)) {

			unsigned long flags;



			local_irq_save(flags);

			buf = kmap_atomic(pc->sg->page, KM_IRQ0) + pc->sg->offset;

			drive->hwif->atapi_output_bytes(drive, buf + pc->b_count, count);

			kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);

			local_irq_restore(flags);

		} else {

			buf = page_address(pc->sg->page) + pc->sg->offset;

			drive->hwif->atapi_output_bytes(drive, buf + pc->b_count, count);

		}

		bcount -= count; pc->b_count += count;

		if (pc->b_count == pc->sg->length) {

			pc->sg++;