[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>

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 35ee35e176c0580e028685fefa5405829891bd37..5e750c33dd9684ce8da629de44f083f63e017fbe 100644 (file)
--- 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;