ide: Fix IDE PIO size calculation

IDE PIO calculates the size wrong when passing the parameter
"ide-core.nodma=0.0" to the kernel.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Acked-by: Steven J. Hill <Steven.Hill@imgtec.com>

Signed-off-by: Steven J. Hill <sjhill@mips.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/ide/ide-taskfile.c

@@ -239,16 +239,15 @@ void ide_pio_bytes(ide_drive_t *drive, struct ide_cmd *cmd,
 		unsigned nr_bytes = min(len, cursg->length - cmd->cursg_ofs);
 		int page_is_high;
 
-		if (nr_bytes > PAGE_SIZE)
-			nr_bytes = PAGE_SIZE;
-
 		page = sg_page(cursg);
 		offset = cursg->offset + cmd->cursg_ofs;
 
 		/* get the current page and offset */
 		page = nth_page(page, (offset >> PAGE_SHIFT));
 		offset %= PAGE_SIZE;
 
+		nr_bytes = min_t(unsigned, nr_bytes, (PAGE_SIZE - offset));
+
 		page_is_high = PageHighMem(page);
 		if (page_is_high)
 			local_irq_save(flags);