* BUG in blkback? on bio generation
@ 2008-12-25 7:48 Y. D.
0 siblings, 0 replies; 2+ messages in thread
From: Y. D. @ 2008-12-25 7:48 UTC (permalink / raw)
To: xen-devel
Hi,
Merry Christmas.
I am reading code in blkback.c, while I find that the bio generation might be really bad.
The bio_add_page() returns length of added bio vector, so if it fails it returns 0.
Therefore, should not bio_add_page() be negated in the while() loop condition??
for (i = 0; i < nseg; i++) {
if (((int)preq.sector_number|(int)seg[i].nsec) &
((bdev_hardsect_size(preq.bdev) >> 9) - 1)) {
DPRINTK("Misaligned I/O request from domain %d",
blkif->domid);
goto fail_put_bio;
}
while ((bio == NULL) ||
-------->(bio_add_page(bio,
virt_to_page(vaddr(pending_req, i)),
seg[i].nsec << 9,
seg[i].buf & ~PAGE_MASK) == 0)) {
bio = biolist[nbio++] = bio_alloc(GFP_KERNEL, nseg-i);
if (unlikely(bio == NULL))
goto fail_put_bio;
bio->bi_bdev = preq.bdev;
bio->bi_private = pending_req;
bio->bi_end_io = end_block_io_op;
bio->bi_sector = preq.sector_number;
}
preq.sector_number += seg[i].nsec;
}
Cheers,
Shawn
^ permalink raw reply [flat|nested] 2+ messages in thread* BUG in blkback? on bio generation
@ 2008-12-25 7:44 Y. D.
0 siblings, 0 replies; 2+ messages in thread
From: Y. D. @ 2008-12-25 7:44 UTC (permalink / raw)
To: xen-devel; +Cc: Keir Fraser
Hi,
Merry Christmas.
I am reading code in blkback.c, while I find that the bio generation might be really bad.
The bio_add_page() returns length of added bio vector, so if it fails it returns 0.
Therefore, should not bio_add_page() be negated in the while() loop condition??
for (i = 0; i < nseg; i++) {
if (((int)preq.sector_number|(int)seg[i].nsec) &
((bdev_hardsect_size(preq.bdev) >> 9) - 1)) {
DPRINTK("Misaligned I/O request from domain %d",
blkif->domid);
goto fail_put_bio;
}
while ((bio == NULL) ||
-------->(bio_add_page(bio,
virt_to_page(vaddr(pending_req, i)),
seg[i].nsec << 9,
seg[i].buf & ~PAGE_MASK) == 0)) {
bio = biolist[nbio++] = bio_alloc(GFP_KERNEL, nseg-i);
if (unlikely(bio == NULL))
goto fail_put_bio;
bio->bi_bdev = preq.bdev;
bio->bi_private = pending_req;
bio->bi_end_io = end_block_io_op;
bio->bi_sector = preq.sector_number;
}
preq.sector_number += seg[i].nsec;
}
Cheers,
Shawn
^ permalink raw reply [flat|nested] 2+ messages in thread
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