fuse: don't use atomic kmap
Don't use atomic kmap for mapping userspace buffers in device
read/write/splice.
This is necessary because the next patch (adding store notify)
requires that caller of fuse_copy_page() may sleep between
invocations. The simplest way to ensure this is to change the atomic
kmaps to non-atomic ones.
Thankfully architectures where kmap() is not a no-op are going out of
fashion, so we can ignore the (probably negligible) performance impact
of this change.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 9424796..7eb80d3 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -535,13 +535,13 @@
if (!cs->write) {
buf->ops->unmap(cs->pipe, buf, cs->mapaddr);
} else {
- kunmap_atomic(cs->mapaddr, KM_USER0);
+ kunmap(buf->page);
buf->len = PAGE_SIZE - cs->len;
}
cs->currbuf = NULL;
cs->mapaddr = NULL;
} else if (cs->mapaddr) {
- kunmap_atomic(cs->mapaddr, KM_USER0);
+ kunmap(cs->pg);
if (cs->write) {
flush_dcache_page(cs->pg);
set_page_dirty_lock(cs->pg);
@@ -572,7 +572,7 @@
BUG_ON(!cs->nr_segs);
cs->currbuf = buf;
- cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
+ cs->mapaddr = buf->ops->map(cs->pipe, buf, 0);
cs->len = buf->len;
cs->buf = cs->mapaddr + buf->offset;
cs->pipebufs++;
@@ -592,7 +592,7 @@
buf->len = 0;
cs->currbuf = buf;
- cs->mapaddr = kmap_atomic(page, KM_USER0);
+ cs->mapaddr = kmap(page);
cs->buf = cs->mapaddr;
cs->len = PAGE_SIZE;
cs->pipebufs++;
@@ -611,7 +611,7 @@
return err;
BUG_ON(err != 1);
offset = cs->addr % PAGE_SIZE;
- cs->mapaddr = kmap_atomic(cs->pg, KM_USER0);
+ cs->mapaddr = kmap(cs->pg);
cs->buf = cs->mapaddr + offset;
cs->len = min(PAGE_SIZE - offset, cs->seglen);
cs->seglen -= cs->len;