[libata irq-pio] use PageHighMem() to optimize the kmap_atomic() usage

as done in ide-scsi.c

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>

1 files changed, 26 insertions, 14 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 35ee35e176c0..5e750c33dd96 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2748,7 +2748,6 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
         struct page *page;
         unsigned int offset;
         unsigned char *buf;
-        unsigned long flags;
 
         if (qc->cursect == (qc->nsect - 1))
                 ap->hsm_task_state = HSM_ST_LAST;
@@ -2762,14 +2761,21 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
 
         DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
 
-        local_irq_save(flags);
-        buf = kmap_atomic(page, KM_IRQ0);
+        if (PageHighMem(page)) {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                buf = kmap_atomic(page, KM_IRQ0);
 
-        /* do the actual data transfer */
-        ata_data_xfer(ap, buf + offset, ATA_SECT_SIZE, do_write);
+                /* do the actual data transfer */
+                ata_data_xfer(ap, buf + offset, ATA_SECT_SIZE, do_write);
 
-        kunmap_atomic(buf, KM_IRQ0);
-        local_irq_restore(flags);
+                kunmap_atomic(buf, KM_IRQ0);
+                local_irq_restore(flags);
+        } else {
+                buf = page_address(page);
+                ata_data_xfer(ap, buf + offset, ATA_SECT_SIZE, do_write);
+        }
 
         qc->cursect++;
         qc->cursg_ofs++;
@@ -2908,7 +2914,6 @@ static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
         struct page *page;
         unsigned char *buf;
         unsigned int offset, count;
-        unsigned long flags;
 
         if (qc->curbytes + bytes >= qc->nbytes)
                 ap->hsm_task_state = HSM_ST_LAST;
@@ -2954,14 +2959,21 @@ next_sg:
 
         DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
 
-        local_irq_save(flags);
-        buf = kmap_atomic(page, KM_IRQ0);
+        if (PageHighMem(page)) {
+                unsigned long flags;
+
+                local_irq_save(flags);
+                buf = kmap_atomic(page, KM_IRQ0);
 
-        /* do the actual data transfer */
-        ata_data_xfer(ap, buf + offset, count, do_write);
+                /* do the actual data transfer */
+                ata_data_xfer(ap, buf + offset, count, do_write);
 
-        kunmap_atomic(buf, KM_IRQ0);
-        local_irq_restore(flags);
+                kunmap_atomic(buf, KM_IRQ0);
+                local_irq_restore(flags);
+        } else {
+                buf = page_address(page);
+                ata_data_xfer(ap, buf + offset, count, do_write);
+        }
 
         bytes -= count;
         qc->curbytes += count;