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 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -535,13 +535,13 @@ static void fuse_copy_finish(struct fuse_copy_state *cs)
                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 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
 
                        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 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
                        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 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
                        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;