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xen/blkback: Move the check for misaligned I/O once more.

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The commit 976222e05e

    xen/blkback: Move the check for misaligned I/O higher.

moved it a bit to high. The preq->vbdev was not set, so the
check for misaligned I/O would cause a NULL pointer derefence.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Konrad Rzeszutek Wilk 2011-04-18 11:34:55 -04:00
parent 9f3aedf573
commit e93504933e
1 changed files with 11 additions and 6 deletions
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17
drivers/xen/blkback/blkback.c
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@ -514,6 +514,7 @@ static void dispatch_rw_block_io(struct blkif_st *blkif,
pending_req->operation = req->operation;
pending_req->status = BLKIF_RSP_OKAY;
pending_req->nr_pages = nseg;
for (i = 0; i < nseg; i++) {
seg[i].nsec = req->u.rw.seg[i].last_sect -
req->u.rw.seg[i].first_sect + 1;
@ -522,12 +523,6 @@ static void dispatch_rw_block_io(struct blkif_st *blkif,
goto fail_response;
preq.nr_sects += seg[i].nsec;
if (((int)preq.sector_number|(int)seg[i].nsec) &
((bdev_logical_block_size(preq.bdev) >> 9) - 1)) {
DPRINTK("Misaligned I/O request from domain %d",
blkif->domid);
goto fail_response;
}
}
if (vbd_translate(&preq, blkif, operation) != 0) {
@ -537,6 +532,16 @@ static void dispatch_rw_block_io(struct blkif_st *blkif,
preq.sector_number + preq.nr_sects, preq.dev);
goto fail_response;
}
/* This check _MUST_ be done after vbd_translate as the preq.bdev
* is set there. */
for (i = 0; i < nseg; i++) {
if (((int)preq.sector_number|(int)seg[i].nsec) &
((bdev_logical_block_size(preq.bdev) >> 9) - 1)) {
DPRINTK("Misaligned I/O request from domain %d",
blkif->domid);
goto fail_response;
}
}
/* If we have failed at this point, we need to undo the M2P override,
* set gnttab_set_unmap_op on all of the grant references and perform
* the hypercall to unmap the grants - that is all done in