From 9f1ffbdc20193b22141857affc2a61bb3519bd67 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 25 Jul 2016 17:34:38 +0100
Subject: [PATCH] block io: rationalise blkdev and swap

blk_op variables want thinning out but that can be done later
---
 Kernel/dev/blkdev.c | 20 ++++++++------------
 Kernel/swap.c       | 25 ++++++++++++++-----------
 2 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/Kernel/dev/blkdev.c b/Kernel/dev/blkdev.c
index 8791ecf0..d0b6460d 100644
--- a/Kernel/dev/blkdev.c
+++ b/Kernel/dev/blkdev.c
@@ -84,29 +84,25 @@ static int blkdev_transfer(uint8_t minor, uint8_t rawflag)
     switch(rawflag){
         case 0:
             /* read single 512-byte sector to buffer in kernel memory */
-            blk_op.nblock = 1;
-            blk_op.lba = udata.u_buf->bf_blk;
-            blk_op.addr = udata.u_buf->bf_data;
             break;
         case 1:
             /* read some number of 512-byte sectors directly to user memory */
-            blk_op.nblock = (udata.u_count >> BLKSHIFT);
-            if((udata.u_count | (uint16_t)udata.u_offset) & BLKMASK)
-                panic("blkdev: not integral");
-            blk_op.lba = (udata.u_offset >> BLKSHIFT);
-            blk_op.addr = udata.u_base;
+            if (d_blkoff(BLKSHIFT))
+                return -1;
             break;
 #ifdef SWAPDEV
         case 2:
-            blk_op.nblock = swapcnt >> BLKSHIFT;
-            blk_op.lba = swapblk;
-            blk_op.addr = swapbase;
             blk_op.swap_page = swappage;
             break;
 #endif
         default:
             goto xferfail;
     }
+    /* FIXME: these should go away now but we need to make u_block some
+       kind of raw blkno_t that can be 32bit optionally */
+    blk_op.nblock = udata.u_nblock;
+    blk_op.lba = udata.u_block;
+    blk_op.addr = udata.u_dptr;
 
     if(partition == 0){
 	/* partition 0 is the whole disk and requires no translation */
@@ -130,7 +126,7 @@ static int blkdev_transfer(uint8_t minor, uint8_t rawflag)
 	blk_op.lba += n;
     }
 
-    return count; /* 10/10, would transfer sectors again */
+    return count << BLKSHIFT; /* 10/10, would transfer sectors again */
 xferfail:
     udata.u_error = EIO;
     return -1;
diff --git a/Kernel/swap.c b/Kernel/swap.c
index 1ae7b4d9..9ff1ea95 100644
--- a/Kernel/swap.c
+++ b/Kernel/swap.c
@@ -12,9 +12,6 @@
 #ifdef SWAPDEV
 
 
-uint8_t *swapbase;
-unsigned int swapcnt;
-blkno_t swapblk;
 uint16_t swappage;			/* Target page */
 
 /* Table of available maps */
@@ -36,15 +33,18 @@ int swapmap_alloc(void)
                 return 0;
 }
 
-/* FIXME: clean this up by having a common i/o structure to avoid
-   all the mode 1 and mode 2 confusion and conversions */
+/* We can re-use udata.u_block and friends as we can never be swapped while
+   we are in the middle of an I/O (at least for now). If we rework the kernel
+   for sleepable I/O this will change */
 
 int swapread(uint16_t dev, blkno_t blkno, unsigned int nbytes,
                     uint16_t buf, uint16_t page)
 {
-	swapbase = swap_map(buf);
-	swapcnt = nbytes;
-	swapblk = blkno;
+	udata.u_dptr = swap_map(buf);
+	udata.u_block = blkno;
+	if (nbytes & BLKMASK)
+		panic("swprd");
+	udata.u_nblock = nbytes >> BLKSHIFT;
 	swappage = page;
 	return ((*dev_tab[major(dev)].dev_read) (minor(dev), 2, 0));
 }
@@ -53,9 +53,12 @@ int swapread(uint16_t dev, blkno_t blkno, unsigned int nbytes,
 int swapwrite(uint16_t dev, blkno_t blkno, unsigned int nbytes,
 		     uint16_t buf, uint16_t page)
 {
-	swapbase = swap_map(buf);
-	swapcnt = nbytes;
-	swapblk = blkno;
+	/* FIXME: duplication here */
+	udata.u_dptr = swap_map(buf);
+	udata.u_block = blkno;
+	if (nbytes & BLKMASK)
+		panic("swpwr");
+	udata.u_nblock = nbytes >> BLKSHIFT;
 	swappage = page;
 	return ((*dev_tab[major(dev)].dev_write) (minor(dev), 2, 0));
 }
-- 
2.34.1