diff --git a/kernel/virtio_disk.c b/kernel/virtio_disk.c
index 14c718d..3cff024 100644
--- a/kernel/virtio_disk.c
+++ b/kernel/virtio_disk.c
@@ -20,36 +20,38 @@
// the address of virtio mmio register r.
#define R(r) ((volatile uint32 *)(VIRTIO0 + (r)))
-struct spinlock vdisk_lock;
+static struct disk {
+ // memory for virtio descriptors &c for queue 0.
+ // this is a global instead of allocated because it must
+ // be multiple contiguous pages, which kalloc()
+ // doesn't support, and page aligned.
+ char pages[2*PGSIZE];
+ struct VRingDesc *desc;
+ uint16 *avail;
+ struct UsedArea *used;
-// memory for virtio descriptors &c for queue 0.
-// this is a global instead of allocated because it has
-// to be multiple contiguous pages, which kalloc()
-// doesn't support.
-__attribute__ ((aligned (PGSIZE)))
-static char pages[2*PGSIZE];
-static struct VRingDesc *desc;
-static uint16 *avail;
-static struct UsedArea *used;
+ // our own book-keeping.
+ char free[NUM]; // is a descriptor free?
+ uint16 used_idx; // we've looked this far in used[2..NUM].
-// our own book-keeping.
-static char free[NUM]; // is a descriptor free?
-static uint16 used_idx; // we've looked this far in used[2..NUM].
-
-// track info about in-flight operations,
-// for use when completion interrupt arrives.
-// indexed by first descriptor index of chain.
-static struct {
- struct buf *b;
- char status;
-} info[NUM];
+ // track info about in-flight operations,
+ // for use when completion interrupt arrives.
+ // indexed by first descriptor index of chain.
+ struct {
+ struct buf *b;
+ char status;
+ } info[NUM];
+
+ struct spinlock vdisk_lock;
+
+} __attribute__ ((aligned (PGSIZE))) disk;
void
virtio_disk_init(void)
{
uint32 status = 0;
- initlock(&vdisk_lock, "virtio_disk");
+ initlock(&disk.vdisk_lock, "virtio_disk");
if(*R(VIRTIO_MMIO_MAGIC_VALUE) != 0x74726976 ||
*R(VIRTIO_MMIO_VERSION) != 1 ||
@@ -93,19 +95,19 @@ virtio_disk_init(void)
if(max < NUM)
panic("virtio disk max queue too short");
*R(VIRTIO_MMIO_QUEUE_NUM) = NUM;
- memset(pages, 0, sizeof(pages));
- *R(VIRTIO_MMIO_QUEUE_PFN) = ((uint64)pages) >> PGSHIFT;
+ memset(disk.pages, 0, sizeof(disk.pages));
+ *R(VIRTIO_MMIO_QUEUE_PFN) = ((uint64)disk.pages) >> PGSHIFT;
// desc = pages -- num * VRingDesc
// avail = pages + 0x40 -- 2 * uint16, then num * uint16
// used = pages + 4096 -- 2 * uint16, then num * vRingUsedElem
- desc = (struct VRingDesc *) pages;
- avail = (uint16*)(((char*)desc) + NUM*sizeof(struct VRingDesc));
- used = (struct UsedArea *) (pages + PGSIZE);
+ disk.desc = (struct VRingDesc *) disk.pages;
+ disk.avail = (uint16*)(((char*)disk.desc) + NUM*sizeof(struct VRingDesc));
+ disk.used = (struct UsedArea *) (disk.pages + PGSIZE);
for(int i = 0; i < NUM; i++)
- free[i] = 1;
+ disk.free[i] = 1;
// plic.c and trap.c arrange for interrupts from VIRTIO0_IRQ.
}
@@ -115,8 +117,8 @@ static int
alloc_desc()
{
for(int i = 0; i < NUM; i++){
- if(free[i]){
- free[i] = 0;
+ if(disk.free[i]){
+ disk.free[i] = 0;
return i;
}
}
@@ -129,11 +131,11 @@ free_desc(int i)
{
if(i >= NUM)
panic("virtio_disk_intr 1");
- if(free[i])
+ if(disk.free[i])
panic("virtio_disk_intr 2");
- desc[i].addr = 0;
- free[i] = 1;
- wakeup(&free[0]);
+ disk.desc[i].addr = 0;
+ disk.free[i] = 1;
+ wakeup(&disk.free[0]);
}
// free a chain of descriptors.
@@ -142,8 +144,8 @@ free_chain(int i)
{
while(1){
free_desc(i);
- if(desc[i].flags & VRING_DESC_F_NEXT)
- i = desc[i].next;
+ if(disk.desc[i].flags & VRING_DESC_F_NEXT)
+ i = disk.desc[i].next;
else
break;
}
@@ -168,7 +170,7 @@ virtio_disk_rw(struct buf *b, int write)
{
uint64 sector = b->blockno * (BSIZE / 512);
- acquire(&vdisk_lock);
+ acquire(&disk.vdisk_lock);
// the spec says that legacy block operations use three
// descriptors: one for type/reserved/sector, one for
@@ -180,7 +182,7 @@ virtio_disk_rw(struct buf *b, int write)
if(alloc3_desc(idx) == 0) {
break;
}
- sleep(&free[0], &vdisk_lock);
+ sleep(&disk.free[0], &disk.vdisk_lock);
}
// format the three descriptors.
@@ -201,67 +203,67 @@ virtio_disk_rw(struct buf *b, int write)
// buf0 is on a kernel stack, which is not direct mapped,
// thus the call to kvmpa().
- desc[idx[0]].addr = (uint64) kvmpa((uint64) &buf0);
- desc[idx[0]].len = sizeof(buf0);
- desc[idx[0]].flags = VRING_DESC_F_NEXT;
- desc[idx[0]].next = idx[1];
+ disk.desc[idx[0]].addr = (uint64) kvmpa((uint64) &buf0);
+ disk.desc[idx[0]].len = sizeof(buf0);
+ disk.desc[idx[0]].flags = VRING_DESC_F_NEXT;
+ disk.desc[idx[0]].next = idx[1];
- desc[idx[1]].addr = (uint64) b->data;
- desc[idx[1]].len = BSIZE;
+ disk.desc[idx[1]].addr = (uint64) b->data;
+ disk.desc[idx[1]].len = BSIZE;
if(write)
- desc[idx[1]].flags = 0; // device reads b->data
+ disk.desc[idx[1]].flags = 0; // device reads b->data
else
- desc[idx[1]].flags = VRING_DESC_F_WRITE; // device writes b->data
- desc[idx[1]].flags |= VRING_DESC_F_NEXT;
- desc[idx[1]].next = idx[2];
+ disk.desc[idx[1]].flags = VRING_DESC_F_WRITE; // device writes b->data
+ disk.desc[idx[1]].flags |= VRING_DESC_F_NEXT;
+ disk.desc[idx[1]].next = idx[2];
- info[idx[0]].status = 0;
- desc[idx[2]].addr = (uint64) &info[idx[0]].status;
- desc[idx[2]].len = 1;
- desc[idx[2]].flags = VRING_DESC_F_WRITE; // device writes the status
- desc[idx[2]].next = 0;
+ disk.info[idx[0]].status = 0;
+ disk.desc[idx[2]].addr = (uint64) &disk.info[idx[0]].status;
+ disk.desc[idx[2]].len = 1;
+ disk.desc[idx[2]].flags = VRING_DESC_F_WRITE; // device writes the status
+ disk.desc[idx[2]].next = 0;
// record struct buf for virtio_disk_intr().
b->disk = 1;
- info[idx[0]].b = b;
+ disk.info[idx[0]].b = b;
// avail[0] is flags
// avail[1] tells the device how far to look in avail[2...].
// avail[2...] are desc[] indices the device should process.
// we only tell device the first index in our chain of descriptors.
- avail[2 + (avail[1] % NUM)] = idx[0];
+ disk.avail[2 + (disk.avail[1] % NUM)] = idx[0];
__sync_synchronize();
- avail[1] = avail[1] + 1;
+ disk.avail[1] = disk.avail[1] + 1;
*R(VIRTIO_MMIO_QUEUE_NOTIFY) = 0; // value is queue number
// Wait for virtio_disk_intr() to say request has finished.
while(b->disk == 1) {
- sleep(b, &vdisk_lock);
+ sleep(b, &disk.vdisk_lock);
}
- info[idx[0]].b = 0;
+ disk.info[idx[0]].b = 0;
free_chain(idx[0]);
- release(&vdisk_lock);
+ release(&disk.vdisk_lock);
}
void
virtio_disk_intr()
{
- acquire(&vdisk_lock);
+ acquire(&disk.vdisk_lock);
- while((used_idx % NUM) != (used->id % NUM)){
- int id = used->elems[used_idx].id;
+ while((disk.used_idx % NUM) != (disk.used->id % NUM)){
+ int id = disk.used->elems[disk.used_idx].id;
- if(info[id].status != 0)
+ if(disk.info[id].status != 0)
panic("virtio_disk_intr status");
- info[id].b->disk = 0; // disk is done with buf
- wakeup(info[id].b);
+ disk.info[id].b->disk = 0; // disk is done with buf
+ wakeup(disk.info[id].b);
- used_idx = (used_idx + 1) % NUM;
+ disk.used_idx = (disk.used_idx + 1) % NUM;
}
- release(&vdisk_lock);
+ release(&disk.vdisk_lock);
}