FreeBSD/Linux Kernel Cross Reference
sys/compat/linuxkpi/common/src/linux_shmemfs.c

     /*-
      * Copyright (c) 2010 Isilon Systems, Inc.
      * Copyright (c) 2016 Matthew Macy (mmacy@mattmacy.io)
      * Copyright (c) 2017 Mellanox Technologies, Ltd.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice unmodified, this list of conditions, and the following
     *    disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/rwlock.h>
    
    #include <vm/vm.h>
    #include <vm/pmap.h>
    #include <vm/vm_object.h>
    #include <vm/vm_map.h>
    #include <vm/vm_page.h>
    #include <vm/vm_pager.h>
    
    #include <linux/fs.h>
    #include <linux/mm.h>
    #include <linux/shmem_fs.h>
    
    struct page *
    linux_shmem_read_mapping_page_gfp(vm_object_t obj, int pindex, gfp_t gfp)
    {
            vm_page_t page;
            int rv;
    
            if ((gfp & GFP_NOWAIT) != 0)
                    panic("GFP_NOWAIT is unimplemented");
    
            VM_OBJECT_WLOCK(obj);
            rv = vm_page_grab_valid(&page, obj, pindex, VM_ALLOC_NORMAL |
                VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
            VM_OBJECT_WUNLOCK(obj);
            if (rv != VM_PAGER_OK)
                    return (ERR_PTR(-EINVAL));
            return (page);
    }
    
    struct linux_file *
    linux_shmem_file_setup(const char *name, loff_t size, unsigned long flags)
    {
            struct fileobj {
                    struct linux_file file __aligned(sizeof(void *));
                    struct vnode vnode __aligned(sizeof(void *));
            };
            struct fileobj *fileobj;
            struct linux_file *filp;
            struct vnode *vp;
            int error;
    
            fileobj = kzalloc(sizeof(*fileobj), GFP_KERNEL);
            if (fileobj == NULL) {
                    error = -ENOMEM;
                    goto err_0;
            }
            filp = &fileobj->file;
            vp = &fileobj->vnode;
    
            filp->f_count = 1;
            filp->f_vnode = vp;
            filp->f_shmem = vm_pager_allocate(OBJT_SWAP, NULL, size,
                VM_PROT_READ | VM_PROT_WRITE, 0, curthread->td_ucred);
            if (filp->f_shmem == NULL) {
                    error = -ENOMEM;
                    goto err_1;
            }
            return (filp);
    err_1:
            kfree(filp);
    err_0:
            return (ERR_PTR(error));
    }
    
   static vm_ooffset_t
   linux_invalidate_mapping_pages_sub(vm_object_t obj, vm_pindex_t start,
       vm_pindex_t end, int flags)
   {
           int start_count, end_count;
   
           VM_OBJECT_WLOCK(obj);
           start_count = obj->resident_page_count;
           vm_object_page_remove(obj, start, end, flags);
           end_count = obj->resident_page_count;
           VM_OBJECT_WUNLOCK(obj);
           return (start_count - end_count);
   }
   
   unsigned long
   linux_invalidate_mapping_pages(vm_object_t obj, pgoff_t start, pgoff_t end)
   {
   
           return (linux_invalidate_mapping_pages_sub(obj, start, end, OBJPR_CLEANONLY));
   }
   
   void
   linux_shmem_truncate_range(vm_object_t obj, loff_t lstart, loff_t lend)
   {
           vm_pindex_t start = OFF_TO_IDX(lstart + PAGE_SIZE - 1);
           vm_pindex_t end = OFF_TO_IDX(lend + 1);
   
           (void) linux_invalidate_mapping_pages_sub(obj, start, end, 0);
   }

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