From 0cbc72a1781250f373327dd7e306e33859a42154 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 11 Nov 2016 18:28:50 -0700 Subject: aoe: fix crash in page count manipulation 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. Reported-by: Tested-by: Don Koch Tested-by: Tested-by: Don Koch Signed-off-by: Jens Axboe --- drivers/block/aoe/aoecmd.c | 41 ----------------------------------------- 1 file changed, 41 deletions(-) (limited to 'drivers/block/aoe') diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c index ab19adb07a12..3c606c09fd5a 100644 --- a/drivers/block/aoe/aoecmd.c +++ b/drivers/block/aoe/aoecmd.c @@ -853,45 +853,6 @@ rqbiocnt(struct request *r) return n; } -/* This can be removed if we are certain that no users of the block - * layer will ever use zero-count pages in bios. Otherwise we have to - * protect against the put_page sometimes done by the network layer. - * - * See http://oss.sgi.com/archives/xfs/2007-01/msg00594.html for - * discussion. - * - * We cannot use get_page in the workaround, because it insists on a - * positive page count as a precondition. So we use _refcount directly. - */ -static void -bio_pageinc(struct bio *bio) -{ - struct bio_vec bv; - struct page *page; - struct bvec_iter iter; - - bio_for_each_segment(bv, bio, iter) { - /* Non-zero page count for non-head members of - * compound pages is no longer allowed by the kernel. - */ - page = compound_head(bv.bv_page); - page_ref_inc(page); - } -} - -static void -bio_pagedec(struct bio *bio) -{ - struct page *page; - struct bio_vec bv; - struct bvec_iter iter; - - bio_for_each_segment(bv, bio, iter) { - page = compound_head(bv.bv_page); - page_ref_dec(page); - } -} - static void bufinit(struct buf *buf, struct request *rq, struct bio *bio) { @@ -899,7 +860,6 @@ bufinit(struct buf *buf, struct request *rq, struct bio *bio) buf->rq = rq; buf->bio = bio; buf->iter = bio->bi_iter; - bio_pageinc(bio); } static struct buf * @@ -1127,7 +1087,6 @@ aoe_end_buf(struct aoedev *d, struct buf *buf) if (buf == d->ip.buf) d->ip.buf = NULL; rq = buf->rq; - bio_pagedec(buf->bio); mempool_free(buf, d->bufpool); n = (unsigned long) rq->special; rq->special = (void *) --n; -- cgit v1.2.3