106 lines
3.2 KiB
Plaintext
106 lines
3.2 KiB
Plaintext
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From: kwolf@suse.de
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Subject: blktap: Write Barriers
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Patch-mainline: obsolete
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--- head-2010-04-29.orig/drivers/xen/blktap/blktap.c 2010-04-29 09:52:39.000000000 +0200
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+++ head-2010-04-29/drivers/xen/blktap/blktap.c 2010-04-29 10:16:10.000000000 +0200
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@@ -1388,6 +1388,9 @@ static int do_block_io_op(blkif_t *blkif
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dispatch_rw_block_io(blkif, &req, pending_req);
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break;
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+ case BLKIF_OP_WRITE_BARRIER:
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+ /* TODO Some counter? */
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+ /* Fall through */
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case BLKIF_OP_WRITE:
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blkif->st_wr_req++;
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dispatch_rw_block_io(blkif, &req, pending_req);
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@@ -1419,7 +1422,7 @@ static void dispatch_rw_block_io(blkif_t
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pending_req_t *pending_req)
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{
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extern void ll_rw_block(int rw, int nr, struct buffer_head * bhs[]);
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- int op, operation = (req->operation == BLKIF_OP_WRITE) ? WRITE : READ;
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+ int op, operation;
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struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST*2];
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unsigned int nseg;
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int ret, i, nr_sects = 0;
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@@ -1431,6 +1434,21 @@ static void dispatch_rw_block_io(blkif_t
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struct mm_struct *mm;
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struct vm_area_struct *vma = NULL;
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+ switch (req->operation) {
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+ case BLKIF_OP_READ:
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+ operation = READ;
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+ break;
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+ case BLKIF_OP_WRITE:
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+ operation = WRITE;
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+ break;
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+ case BLKIF_OP_WRITE_BARRIER:
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+ operation = WRITE_BARRIER;
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+ break;
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+ default:
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+ operation = 0; /* make gcc happy */
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+ BUG();
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+ }
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+
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if (blkif->dev_num < 0 || blkif->dev_num >= MAX_TAP_DEV)
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goto fail_response;
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@@ -1470,7 +1488,7 @@ static void dispatch_rw_block_io(blkif_t
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pending_req->blkif = blkif;
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pending_req->id = req->id;
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- pending_req->operation = operation;
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+ pending_req->operation = req->operation;
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pending_req->status = BLKIF_RSP_OKAY;
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pending_req->nr_pages = nseg;
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op = 0;
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@@ -1487,7 +1505,7 @@ static void dispatch_rw_block_io(blkif_t
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kvaddr = idx_to_kaddr(mmap_idx, pending_idx, i);
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flags = GNTMAP_host_map;
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- if (operation == WRITE)
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+ if (operation != READ)
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flags |= GNTMAP_readonly;
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gnttab_set_map_op(&map[op], kvaddr, flags,
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req->seg[i].gref, blkif->domid);
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@@ -1504,7 +1522,7 @@ static void dispatch_rw_block_io(blkif_t
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flags = GNTMAP_host_map | GNTMAP_application_map
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| GNTMAP_contains_pte;
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- if (operation == WRITE)
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+ if (operation != READ)
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flags |= GNTMAP_readonly;
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gnttab_set_map_op(&map[op], ptep, flags,
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req->seg[i].gref, blkif->domid);
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--- head-2010-04-29.orig/drivers/xen/blktap/xenbus.c 2010-04-29 10:15:31.000000000 +0200
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+++ head-2010-04-29/drivers/xen/blktap/xenbus.c 2010-04-29 10:16:08.000000000 +0200
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@@ -402,7 +402,28 @@ static void connect(struct backend_info
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int err;
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struct xenbus_device *dev = be->dev;
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+ struct xenbus_transaction xbt;
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+ /* Write feature-barrier to xenstore */
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+again:
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+ err = xenbus_transaction_start(&xbt);
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+ if (err) {
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+ xenbus_dev_fatal(dev, err, "starting transaction");
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+ return;
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+ }
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+
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+ err = xenbus_printf(xbt, dev->nodename, "feature-barrier", "1");
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+ if (err) {
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+ xenbus_dev_fatal(dev, err, "writing feature-barrier");
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+ xenbus_transaction_end(xbt, 1);
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+ return;
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+ }
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+
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+ err = xenbus_transaction_end(xbt, 0);
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+ if (err == -EAGAIN)
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+ goto again;
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+
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+ /* Switch state */
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err = xenbus_switch_state(dev, XenbusStateConnected);
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if (err)
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xenbus_dev_fatal(dev, err, "switching to Connected state",
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