diff options
| author | Bart Van Assche <bart.vanassche@wdc.com> | 2018-01-19 11:00:54 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-01-19 12:31:03 -0700 |
| commit | 8c7a8d1c4b9c30a2be3b31a2e6af1cefd45574eb (patch) | |
| tree | 0a539f04d39495479b9a4965ace69aad45c01cf9 /lib | |
| parent | 9b9c63f71bddf3dc897aaaa46c0593abc3e09932 (diff) | |
lib/scatterlist: Fix chaining support in sgl_alloc_order()
This patch avoids that workloads with large block sizes (megabytes)
can trigger the following call stack with the ib_srpt driver (that
driver is the only driver that chains scatterlists allocated by
sgl_alloc_order()):
BUG: Bad page state in process kworker/0:1H pfn:2423a78
page:fffffb03d08e9e00 count:-3 mapcount:0 mapping: (null) index:0x0
flags: 0x57ffffc0000000()
raw: 0057ffffc0000000 0000000000000000 0000000000000000 fffffffdffffffff
raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000
page dumped because: nonzero _count
CPU: 0 PID: 733 Comm: kworker/0:1H Tainted: G I 4.15.0-rc7.bart+ #1
Hardware name: HP ProLiant DL380 G7, BIOS P67 08/16/2015
Workqueue: ib-comp-wq ib_cq_poll_work [ib_core]
Call Trace:
dump_stack+0x5c/0x83
bad_page+0xf5/0x10f
get_page_from_freelist+0xa46/0x11b0
__alloc_pages_nodemask+0x103/0x290
sgl_alloc_order+0x101/0x180
target_alloc_sgl+0x2c/0x40 [target_core_mod]
srpt_alloc_rw_ctxs+0x173/0x2d0 [ib_srpt]
srpt_handle_new_iu+0x61e/0x7f0 [ib_srpt]
__ib_process_cq+0x55/0xa0 [ib_core]
ib_cq_poll_work+0x1b/0x60 [ib_core]
process_one_work+0x141/0x340
worker_thread+0x47/0x3e0
kthread+0xf5/0x130
ret_from_fork+0x1f/0x30
Fixes: e80a0af4759a ("lib/scatterlist: Introduce sgl_alloc() and sgl_free()")
Reported-by: Laurence Oberman <loberman@redhat.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/scatterlist.c | 32 |
1 files changed, 27 insertions, 5 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 9afc9b432083..53728d391d3a 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -512,7 +512,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length, if (!sgl) return NULL; - sg_init_table(sgl, nent); + sg_init_table(sgl, nalloc); sg = sgl; while (length) { elem_len = min_t(u64, length, PAGE_SIZE << order); @@ -526,7 +526,7 @@ struct scatterlist *sgl_alloc_order(unsigned long long length, length -= elem_len; sg = sg_next(sg); } - WARN_ON_ONCE(sg); + WARN_ONCE(length, "length = %lld\n", length); if (nent_p) *nent_p = nent; return sgl; @@ -549,22 +549,44 @@ struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, EXPORT_SYMBOL(sgl_alloc); /** - * sgl_free_order - free a scatterlist and its pages + * sgl_free_n_order - free a scatterlist and its pages * @sgl: Scatterlist with one or more elements + * @nents: Maximum number of elements to free * @order: Second argument for __free_pages() + * + * Notes: + * - If several scatterlists have been chained and each chain element is + * freed separately then it's essential to set nents correctly to avoid that a + * page would get freed twice. + * - All pages in a chained scatterlist can be freed at once by setting @nents + * to a high number. */ -void sgl_free_order(struct scatterlist *sgl, int order) +void sgl_free_n_order(struct scatterlist *sgl, int nents, int order) { struct scatterlist *sg; struct page *page; + int i; - for (sg = sgl; sg; sg = sg_next(sg)) { + for_each_sg(sgl, sg, nents, i) { + if (!sg) + break; page = sg_page(sg); if (page) __free_pages(page, order); } kfree(sgl); } +EXPORT_SYMBOL(sgl_free_n_order); + +/** + * sgl_free_order - free a scatterlist and its pages + * @sgl: Scatterlist with one or more elements + * @order: Second argument for __free_pages() + */ +void sgl_free_order(struct scatterlist *sgl, int order) +{ + sgl_free_n_order(sgl, INT_MAX, order); +} EXPORT_SYMBOL(sgl_free_order); /** |