Hi Mike, On Sat, Dec 19, 2020 at 11:12 AM Mike Galbraith <efa...@gmx.de> wrote: > > (mailer partially munged formatting? resend) > > mm/zswap: fix zswap_frontswap_load() vs zsmalloc::map/unmap() might_sleep() > splat > > zsmalloc map/unmap methods use preemption disabling bit spinlocks. Take the > mutex outside of pool map/unmap methods in zswap_frontswap_load() as is done > in zswap_frontswap_store().
oh wait... So is zsmalloc taking a spin lock in its map callback and releasing it only in unmap? In this case, I would rather keep zswap as is, mark zsmalloc as RT unsafe and have zsmalloc maintainer fix it. Best regards, Vitaly > Signed-off-by: Mike Galbraith <efa...@gmx.de> > Fixes: 1ec3b5fe6eec "mm/zswap: move to use crypto_acomp API for hardware > acceleration" > --- > mm/zswap.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -1258,20 +1258,20 @@ static int zswap_frontswap_load(unsigned > > /* decompress */ > dlen = PAGE_SIZE; > + acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); > + mutex_lock(acomp_ctx->mutex); > src = zpool_map_handle(entry->pool->zpool, entry->handle, > ZPOOL_MM_RO); > if (zpool_evictable(entry->pool->zpool)) > src += sizeof(struct zswap_header); > > - acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); > - mutex_lock(acomp_ctx->mutex); > sg_init_one(&input, src, entry->length); > sg_init_table(&output, 1); > sg_set_page(&output, page, PAGE_SIZE, 0); > acomp_request_set_params(acomp_ctx->req, &input, &output, > entry->length, dlen); > ret = crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), > &acomp_ctx->wait); > - mutex_unlock(acomp_ctx->mutex); > > zpool_unmap_handle(entry->pool->zpool, entry->handle); > + mutex_unlock(acomp_ctx->mutex); > BUG_ON(ret); > > freeentry: >
