[PATCH] revert ide-scsi highmem cleanup

Jeff Garzik <jgarzik@pobox.com> points out that this was wrong: we need to
disable local interrupts while holding KM_IRQ0 due to IRQ sharing.

And holding interrupts off during a big PIO opration is expensive, so we only
want to do that if we know the page was highmem.

So revert commit 17fd47ab4d33e764216b87006d8118fa050b4c92

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 32 insertions, 12 deletions

diff --git a/drivers/scsi/ide-scsi.c b/drivers/scsi/ide-scsi.c
index 00d6a6657eb..a440ea38efa 100644
--- a/drivers/scsi/ide-scsi.c
+++ b/drivers/scsi/ide-scsi.c
@@ -180,12 +180,22 @@ static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigne
                         return;
                 }
                 count = min(pc->sg->length - pc->b_count, bcount);
-                buf = kmap_atomic(pc->sg->page, KM_IRQ0);
-                drive->hwif->atapi_input_bytes(drive,
-                                buf + pc->b_count + pc->sg->offset, count);
-                kunmap_atomic(buf, KM_IRQ0);
-                bcount -= count;
-                pc->b_count += count;
+                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++;
                         pc->b_count = 0;
@@ -205,12 +215,22 @@ static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsign
                         return;
                 }
                 count = min(pc->sg->length - pc->b_count, bcount);
-                buf = kmap_atomic(pc->sg->page, KM_IRQ0);
-                drive->hwif->atapi_output_bytes(drive,
-                                buf + pc->b_count + pc->sg->offset, count);
-                kunmap_atomic(buf, KM_IRQ0);
-                bcount -= count;
-                pc->b_count += count;
+                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++;
                         pc->b_count = 0;