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122 lines
4.5 KiB
122 lines
4.5 KiB
From ef0d243bfeaf1da8854c26f89536dc1b69c56602 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
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<marmarek@invisiblethingslab.com>
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Date: Wed, 16 Dec 2015 05:51:10 +0100
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Subject: [PATCH 12/13] xen-blkfront: make local copy of response before using
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it
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Organization: Invisible Things Lab
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Cc: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
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Data on the shared page can be changed at any time by the backend. Make
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a local copy, which is no longer controlled by the backend. And only
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then access it.
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This is part of XSA155.
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CC: stable@vger.kernel.org
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Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
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---
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drivers/block/xen-blkfront.c | 34 +++++++++++++++++-----------------
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1 file changed, 17 insertions(+), 17 deletions(-)
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diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
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index 2fee2ee..5d7eb04 100644
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--- a/drivers/block/xen-blkfront.c
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+++ b/drivers/block/xen-blkfront.c
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@@ -1296,7 +1296,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
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static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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{
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struct request *req;
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- struct blkif_response *bret;
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+ struct blkif_response bret;
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RING_IDX i, rp;
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unsigned long flags;
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struct blkfront_info *info = (struct blkfront_info *)dev_id;
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@@ -1316,8 +1316,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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for (i = info->ring.rsp_cons; i != rp; i++) {
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unsigned long id;
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- bret = RING_GET_RESPONSE(&info->ring, i);
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- id = bret->id;
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+ RING_COPY_RESPONSE(&info->ring, i, &bret);
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+ id = bret.id;
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/*
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* The backend has messed up and given us an id that we would
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* never have given to it (we stamp it up to BLK_RING_SIZE -
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@@ -1325,29 +1325,29 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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*/
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if (id >= BLK_RING_SIZE) {
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WARN(1, "%s: response to %s has incorrect id (%ld)\n",
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- info->gd->disk_name, op_name(bret->operation), id);
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+ info->gd->disk_name, op_name(bret.operation), id);
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/* We can't safely get the 'struct request' as
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* the id is busted. */
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continue;
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}
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req = info->shadow[id].request;
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- if (bret->operation != BLKIF_OP_DISCARD)
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- blkif_completion(&info->shadow[id], info, bret);
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+ if (bret.operation != BLKIF_OP_DISCARD)
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+ blkif_completion(&info->shadow[id], info, &bret);
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if (add_id_to_freelist(info, id)) {
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WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
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- info->gd->disk_name, op_name(bret->operation), id);
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+ info->gd->disk_name, op_name(bret.operation), id);
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continue;
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}
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- error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
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- switch (bret->operation) {
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+ error = (bret.status == BLKIF_RSP_OKAY) ? 0 : -EIO;
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+ switch (bret.operation) {
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case BLKIF_OP_DISCARD:
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- if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
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+ if (unlikely(bret.status == BLKIF_RSP_EOPNOTSUPP)) {
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struct request_queue *rq = info->rq;
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printk(KERN_WARNING "blkfront: %s: %s op failed\n",
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- info->gd->disk_name, op_name(bret->operation));
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+ info->gd->disk_name, op_name(bret.operation));
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error = -EOPNOTSUPP;
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info->feature_discard = 0;
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info->feature_secdiscard = 0;
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@@ -1358,15 +1358,15 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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break;
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case BLKIF_OP_FLUSH_DISKCACHE:
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case BLKIF_OP_WRITE_BARRIER:
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- if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
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+ if (unlikely(bret.status == BLKIF_RSP_EOPNOTSUPP)) {
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printk(KERN_WARNING "blkfront: %s: %s op failed\n",
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- info->gd->disk_name, op_name(bret->operation));
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+ info->gd->disk_name, op_name(bret.operation));
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error = -EOPNOTSUPP;
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}
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- if (unlikely(bret->status == BLKIF_RSP_ERROR &&
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+ if (unlikely(bret.status == BLKIF_RSP_ERROR &&
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info->shadow[id].req.u.rw.nr_segments == 0)) {
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printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
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- info->gd->disk_name, op_name(bret->operation));
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+ info->gd->disk_name, op_name(bret.operation));
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error = -EOPNOTSUPP;
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}
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if (unlikely(error)) {
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@@ -1378,9 +1378,9 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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/* fall through */
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case BLKIF_OP_READ:
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case BLKIF_OP_WRITE:
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- if (unlikely(bret->status != BLKIF_RSP_OKAY))
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+ if (unlikely(bret.status != BLKIF_RSP_OKAY))
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dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
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- "request: %x\n", bret->status);
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+ "request: %x\n", bret.status);
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__blk_end_request_all(req, error);
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break;
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--
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2.1.0
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