[Xen-changelog] Fixes for blkif save/restore. A 'dd if=/dev/sda1 of=/dev/null'

[Xen patchbot -unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 1643f6110469db41ecb4859f2f88f0c3948edd9a
# Parent  9e0b6fbab872914c07f837e0d53142f3cb9cfee5
Fixes for blkif save/restore. A 'dd if=/dev/sda1 of=/dev/null'
seems to lock up the domU kernel on restore still (can be
pinged but not ssh'ed). This still needs investigation.

Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>

diff -r 9e0b6fbab872 -r 1643f6110469 
linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
--- a/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c      Wed Sep 28 
16:02:17 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c      Wed Sep 28 
16:25:08 2005
@@ -57,10 +57,7 @@
 
 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \
     (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLKIF_RING_SIZE)
-#define GRANTREF_INVALID (1<<15)
 #define GRANT_INVALID_REF      (0xFFFF)
-
-static int recovery = 0; /* Recovery in progress: protected by blkif_io_lock */
 
 static void kick_pending_request_queues(struct blkfront_info *info);
 
@@ -82,18 +79,6 @@
        info->shadow[id].req.id  = info->shadow_free;
        info->shadow[id].request = 0;
        info->shadow_free = id;
-}
-
-static inline void pickle_request(struct blk_shadow *s, blkif_request_t *r)
-{
-
-       s->req = *r;
-}
-
-static inline void unpickle_request(blkif_request_t *r, struct blk_shadow *s)
-{
-
-       *r = s->req;
 }
 
 static inline void flush_requests(struct blkfront_info *info)
@@ -235,7 +220,7 @@
                                rq_data_dir(req) );
 
                        info->shadow[id].frame[ring_req->nr_segments] =
-                               buffer_mfn;
+                               mfn_to_pfn(buffer_mfn);
 
                        ring_req->frame_and_sects[ring_req->nr_segments] =
                                blkif_fas_from_gref(ref, fsect, lsect);
@@ -247,7 +232,7 @@
        info->ring.req_prod_pvt++;
 
        /* Keep a private copy so we can reissue requests when recovering. */
-       pickle_request(&info->shadow[id], ring_req);
+       info->shadow[id].req = *ring_req;
 
        gnttab_free_grant_references(gref_head);
 
@@ -312,7 +297,7 @@
 
        spin_lock_irqsave(&blkif_io_lock, flags);
 
-       if (unlikely(info->connected != BLKIF_STATE_CONNECTED || recovery)) {
+       if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
                spin_unlock_irqrestore(&blkif_io_lock, flags);
                return IRQ_HANDLED;
        }
@@ -401,36 +386,30 @@
                if (copy[i].request == 0)
                        continue;
 
-               /* Grab a request slot and unpickle shadow state into it. */
+               /* Grab a request slot and copy shadow state into it. */
                req = RING_GET_REQUEST(
                        &info->ring, info->ring.req_prod_pvt);
-               unpickle_request(req, &copy[i]);
+               *req = copy[i].req;
 
                /* We get a new request id, and must reset the shadow state. */
                req->id = GET_ID_FROM_FREELIST(info);
                memcpy(&info->shadow[req->id], &copy[i], sizeof(copy[i]));
 
                /* Rewrite any grant references invalidated by susp/resume. */
-               for (j = 0; j < req->nr_segments; j++) {
-                       if ( req->frame_and_sects[j] & GRANTREF_INVALID )
-                               gnttab_grant_foreign_access_ref(
-                                       blkif_gref_from_fas(
-                                               req->frame_and_sects[j]),
-                                       info->backend_id,
-                                       info->shadow[req->id].frame[j],
-                                       rq_data_dir(
-                                               (struct request *)
-                                               info->shadow[req->id].request));
-                       req->frame_and_sects[j] &= ~GRANTREF_INVALID;
-               }
+               for (j = 0; j < req->nr_segments; j++)
+                       gnttab_grant_foreign_access_ref(
+                               blkif_gref_from_fas(req->frame_and_sects[j]),
+                               info->backend_id,
+                               pfn_to_mfn(info->shadow[req->id].frame[j]),
+                               rq_data_dir(
+                                       (struct request *)
+                                       info->shadow[req->id].request));
                info->shadow[req->id].req = *req;
 
                info->ring.req_prod_pvt++;
        }
 
        kfree(copy);
-
-       recovery = 0;
 
        /* info->ring->req_prod will be set when we flush_requests().*/
        wmb();
@@ -438,7 +417,7 @@
        /* Kicks things back into life. */
        flush_requests(info);
 
-       /* Now safe to left other people use the interface. */
+       /* Now safe to let other people use the interface. */
        info->connected = BLKIF_STATE_CONNECTED;
 }
 
@@ -701,7 +680,6 @@
        kfree(info->backend);
        info->backend = NULL;
 
-       recovery = 1;
        blkif_free(info);
 
        return 0;
diff -r 9e0b6fbab872 -r 1643f6110469 
linux-2.6-xen-sparse/drivers/xen/netback/common.h
--- a/linux-2.6-xen-sparse/drivers/xen/netback/common.h Wed Sep 28 16:02:17 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/netback/common.h Wed Sep 28 16:25:08 2005
@@ -21,8 +21,6 @@
 #include <asm-xen/xen-public/grant_table.h>
 #include <asm-xen/gnttab.h>
 #include <asm-xen/driver_util.h>
-
-#define GRANT_INVALID_REF (0xFFFF)
 
 #if 0
 #define ASSERT(_p) \
diff -r 9e0b6fbab872 -r 1643f6110469 
linux-2.6-xen-sparse/drivers/xen/netback/netback.c
--- a/linux-2.6-xen-sparse/drivers/xen/netback/netback.c        Wed Sep 28 
16:02:17 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/netback/netback.c        Wed Sep 28 
16:25:08 2005
@@ -434,7 +434,6 @@
                gop->host_addr    = MMAP_VADDR(pending_idx);
                gop->dev_bus_addr = 0;
                gop->handle       = grant_tx_ref[pending_idx];
-               grant_tx_ref[pending_idx] = GRANT_INVALID_REF;
                gop++;
        }
        BUG_ON(HYPERVISOR_grant_table_op(

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