fuse: use kmap_local_page()

Due to the introduction of kmap_local_*, the storage of slots used for
short-term mapping has changed from per-CPU to per-thread.  kmap_atomic()
disable preemption, while kmap_local_*() only disable migration.

There is no need to disable preemption in several kamp_atomic places used
in fuse.

Link: https://lwn.net/Articles/836144/
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/dev.c

@@ -756,15 +756,15 @@ static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 {
 	unsigned ncpy = min(*size, cs->len);
 	if (val) {
-		void *pgaddr = kmap_atomic(cs->pg);
+		void *pgaddr = kmap_local_page(cs->pg);
 		void *buf = pgaddr + cs->offset;
 
 		if (cs->write)
 			memcpy(buf, *val, ncpy);
 		else
 			memcpy(*val, buf, ncpy);
 
-		kunmap_atomic(pgaddr);
+		kunmap_local(pgaddr);
 		*val += ncpy;
 	}
 	*size -= ncpy;
@@ -949,10 +949,10 @@ static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 			}
 		}
 		if (page) {
-			void *mapaddr = kmap_atomic(page);
+			void *mapaddr = kmap_local_page(page);
 			void *buf = mapaddr + offset;
 			offset += fuse_copy_do(cs, &buf, &count);
-			kunmap_atomic(mapaddr);
+			kunmap_local(mapaddr);
 		} else
 			offset += fuse_copy_do(cs, NULL, &count);
 	}

fs/fuse/ioctl.c

@@ -286,11 +286,11 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 		    in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
 			goto out;
 
-		vaddr = kmap_atomic(ap.pages[0]);
+		vaddr = kmap_local_page(ap.pages[0]);
 		err = fuse_copy_ioctl_iovec(fm->fc, iov_page, vaddr,
 					    transferred, in_iovs + out_iovs,
 					    (flags & FUSE_IOCTL_COMPAT) != 0);
-		kunmap_atomic(vaddr);
+		kunmap_local(vaddr);
 		if (err)
 			goto out;
 

fs/fuse/readdir.c

@@ -76,11 +76,11 @@ static void fuse_add_dirent_to_cache(struct file *file,
 	    WARN_ON(fi->rdc.pos != pos))
 		goto unlock;
 
-	addr = kmap_atomic(page);
+	addr = kmap_local_page(page);
 	if (!offset)
 		clear_page(addr);
 	memcpy(addr + offset, dirent, reclen);
-	kunmap_atomic(addr);
+	kunmap_local(addr);
 	fi->rdc.size = (index << PAGE_SHIFT) + offset + reclen;
 	fi->rdc.pos = dirent->off;
 unlock: