1 /* $NetBSD: shmem_fs.h,v 1.5 2022/08/20 23:49:31 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #ifndef _LINUX_SHMEM_FS_H_ 33 #define _LINUX_SHMEM_FS_H_ 34 35 #include <sys/types.h> 36 #include <sys/param.h> 37 38 #include <sys/rwlock.h> 39 40 #include <lib/libkern/libkern.h> 41 42 #include <uvm/uvm_extern.h> 43 #include <uvm/uvm_object.h> 44 45 #include <linux/err.h> 46 #include <linux/gfp.h> 47 #include <linux/mm_types.h> 48 49 static inline struct page * 50 shmem_read_mapping_page_gfp(struct uvm_object *uobj, voff_t i, gfp_t gfp) 51 { 52 struct vm_page *vm_page; 53 int error; 54 55 error = uvm_obj_wirepages(uobj, i*PAGE_SIZE, (i + 1)*PAGE_SIZE, NULL); 56 if (error) 57 return ERR_PTR(-error); /* XXX errno NetBSD->Linux */ 58 59 rw_enter(uobj->vmobjlock, RW_READER); 60 vm_page = uvm_pagelookup(uobj, i*PAGE_SIZE); 61 rw_exit(uobj->vmobjlock); 62 63 KASSERT(vm_page); 64 return container_of(vm_page, struct page, p_vmp); 65 } 66 67 static inline struct page * 68 shmem_read_mapping_page(struct uvm_object *uobj, voff_t i) 69 { 70 return shmem_read_mapping_page_gfp(uobj, i, GFP_KERNEL); 71 } 72 73 static inline void 74 shmem_truncate_range(struct uvm_object *uobj, voff_t start, voff_t end) 75 { 76 int flags = PGO_FREE; 77 78 if (start == 0 && end == -1) { 79 flags |= PGO_ALLPAGES; 80 } else { 81 KASSERT(0 <= start); 82 KASSERT(start <= end); 83 } 84 85 rw_enter(uobj->vmobjlock, RW_WRITER); 86 (*uobj->pgops->pgo_put)(uobj, start, end, flags); 87 } 88 89 #endif /* _LINUX_SHMEM_FS_H_ */ 90