cregit-Linux how code gets into the kernel

Release 4.10 fs/romfs/mmap-nommu.c

Directory: fs/romfs
/* NOMMU mmap support for RomFS on MTD devices
 * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.

#include <linux/mm.h>
#include <linux/mtd/super.h>
#include "internal.h"

 * try to determine where a shared mapping can be made
 * - only supported for NOMMU at the moment (MMU can't doesn't copy private
 *   mappings)
 * - attempts to map through to the underlying MTD device

static unsigned long romfs_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct inode *inode = file->f_mapping->host; struct mtd_info *mtd = inode->i_sb->s_mtd; unsigned long isize, offset, maxpages, lpages; int ret; if (!mtd) return (unsigned long) -ENOSYS; /* the mapping mustn't extend beyond the EOF */ lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; isize = i_size_read(inode); offset = pgoff << PAGE_SHIFT; maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT; if ((pgoff >= maxpages) || (maxpages - pgoff < lpages)) return (unsigned long) -EINVAL; if (addr != 0) return (unsigned long) -EINVAL; if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT)) return (unsigned long) -EINVAL; offset += ROMFS_I(inode)->i_dataoffset; if (offset >= mtd->size) return (unsigned long) -EINVAL; /* the mapping mustn't extend beyond the EOF */ if ((offset + len) > mtd->size) len = mtd->size - offset; ret = mtd_get_unmapped_area(mtd, len, offset, flags); if (ret == -EOPNOTSUPP) ret = -ENOSYS; return (unsigned long) ret; }


david howellsdavid howells16664.84%120.00%
bob liubob liu4015.62%120.00%
artem bityutskiyartem bityutskiy2810.94%240.00%
greg ungerergreg ungerer228.59%120.00%

/* * permit a R/O mapping to be made directly through onto an MTD device if * possible */
static int romfs_mmap(struct file *file, struct vm_area_struct *vma) { return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS; }


david howellsdavid howells32100.00%1100.00%

static unsigned romfs_mmap_capabilities(struct file *file) { struct mtd_info *mtd = file_inode(file)->i_sb->s_mtd; if (!mtd) return NOMMU_MAP_COPY; return mtd_mmap_capabilities(mtd); }


christoph hellwigchristoph hellwig39100.00%1100.00%

const struct file_operations romfs_ro_fops = { .llseek = generic_file_llseek, .read_iter = generic_file_read_iter, .splice_read = generic_file_splice_read, .mmap = romfs_mmap, .get_unmapped_area = romfs_get_unmapped_area, .mmap_capabilities = romfs_mmap_capabilities, };

Overall Contributors

david howellsdavid howells24063.83%114.29%
christoph hellwigchristoph hellwig4411.70%114.29%
bob liubob liu4010.64%114.29%
artem bityutskiyartem bityutskiy287.45%228.57%
greg ungerergreg ungerer225.85%114.29%
al viroal viro20.53%114.29%
Directory: fs/romfs
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