aoeblk contains some mysterious code, that wants to elevate the bio vec page counts while it's under IO. That is not needed, it's fragile, and it's causing kernel oopses for some.
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| @@ -853,45 +853,6 @@ rqbiocnt(struct request *r) · 852 unmodified lines | |||
| 853 | return n; | 853 | return n; |
| 854 | } | 854 | } |
| 855 | 855 | ||
| 856 | /* This can be removed if we are certain that no users of the block | ||
| 857 | * layer will ever use zero-count pages in bios. Otherwise we have to | ||
| 858 | * protect against the put_page sometimes done by the network layer. | ||
| 859 | * | ||
| 860 | * See http://oss.sgi.com/archives/xfs/2007-01/msg00594.html for | ||
| 861 | * discussion. | ||
| 862 | * | ||
| 863 | * We cannot use get_page in the workaround, because it insists on a | ||
| 864 | * positive page count as a precondition. So we use _refcount directly. | ||
| 865 | */ | ||
| 866 | static void | ||
| 867 | bio_pageinc(struct bio *bio) | ||
| 868 | { | ||
| 869 | struct bio_vec bv; | ||
| 870 | struct page *page; | ||
| 871 | struct bvec_iter iter; | ||
| 872 | |||
| 873 | bio_for_each_segment(bv, bio, iter) { | ||
| 874 | /* Non-zero page count for non-head members of | ||
| 875 | * compound pages is no longer allowed by the kernel. | ||
| 876 | */ | ||
| 877 | page = compound_head(bv.bv_page); | ||
| 878 | page_ref_inc(page); | ||
| 879 | } | ||
| 880 | } | ||
| 881 | |||
| 882 | static void | ||
| 883 | bio_pagedec(struct bio *bio) | ||
| 884 | { | ||
| 885 | struct page *page; | ||
| 886 | struct bio_vec bv; | ||
| 887 | struct bvec_iter iter; | ||
| 888 | |||
| 889 | bio_for_each_segment(bv, bio, iter) { | ||
| 890 | page = compound_head(bv.bv_page); | ||
| 891 | page_ref_dec(page); | ||
| 892 | } | ||
| 893 | } | ||
| 894 | |||
| 895 | static void | 856 | static void |
| 896 | bufinit(struct buf *buf, struct request *rq, struct bio *bio) | 857 | bufinit(struct buf *buf, struct request *rq, struct bio *bio) |
| 897 | { | 858 | { |
| @@ -899,7 +860,6 @@ bufinit(struct buf *buf, struct request *rq, struct bio *bio) · 1 unmodified line | |||
| 899 | buf->rq = rq; | 860 | buf->rq = rq; |
| 900 | buf->bio = bio; | 861 | buf->bio = bio; |
| 901 | buf->iter = bio->bi_iter; | 862 | buf->iter = bio->bi_iter; |
| 902 | bio_pageinc(bio); | ||
| 903 | } | 863 | } |
| 904 | 864 | ||
| 905 | static struct buf * | 865 | static struct buf * |
| @@ -1127,7 +1087,6 @@ aoe_end_buf(struct aoedev *d, struct buf *buf) · 221 unmodified lines | |||
| 1127 | if (buf == d->ip.buf) | 1087 | if (buf == d->ip.buf) |
| 1128 | d->ip.buf = NULL; | 1088 | d->ip.buf = NULL; |
| 1129 | rq = buf->rq; | 1089 | rq = buf->rq; |
| 1130 | bio_pagedec(buf->bio); | ||
| 1131 | mempool_free(buf, d->bufpool); | 1090 | mempool_free(buf, d->bufpool); |
| 1132 | n = (unsigned long) rq->special; | 1091 | n = (unsigned long) rq->special; |
| 1133 | rq->special = (void *) --n; | 1092 | rq->special = (void *) --n; |