mirror of
https://github.com/torvalds/linux
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70688e4dd1
Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for the user mappings. This requires the get_xip_page API to be changed to an address based one. Improve the API layering a little bit too, while we're here. This is required in order to support XIP filesystems on memory that isn't backed with struct page (but memory with struct page is still supported too). Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Carsten Otte <cotte@de.ibm.com> Cc: Jared Hulbert <jaredeh@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
138 lines
2.9 KiB
C
138 lines
2.9 KiB
C
/*
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* mm/fadvise.c
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*
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* Copyright (C) 2002, Linus Torvalds
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*
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* 11Jan2003 akpm@digeo.com
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* Initial version.
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*/
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#include <linux/kernel.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <linux/backing-dev.h>
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#include <linux/pagevec.h>
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#include <linux/fadvise.h>
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#include <linux/writeback.h>
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#include <linux/syscalls.h>
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#include <asm/unistd.h>
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/*
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* POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
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* deactivate the pages and clear PG_Referenced.
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*/
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asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
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{
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struct file *file = fget(fd);
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struct address_space *mapping;
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struct backing_dev_info *bdi;
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loff_t endbyte; /* inclusive */
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pgoff_t start_index;
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pgoff_t end_index;
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unsigned long nrpages;
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int ret = 0;
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if (!file)
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return -EBADF;
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if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
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ret = -ESPIPE;
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goto out;
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}
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mapping = file->f_mapping;
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if (!mapping || len < 0) {
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ret = -EINVAL;
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goto out;
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}
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if (mapping->a_ops->get_xip_mem) {
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switch (advice) {
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case POSIX_FADV_NORMAL:
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case POSIX_FADV_RANDOM:
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case POSIX_FADV_SEQUENTIAL:
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case POSIX_FADV_WILLNEED:
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case POSIX_FADV_NOREUSE:
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case POSIX_FADV_DONTNEED:
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/* no bad return value, but ignore advice */
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break;
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default:
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ret = -EINVAL;
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}
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goto out;
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}
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/* Careful about overflows. Len == 0 means "as much as possible" */
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endbyte = offset + len;
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if (!len || endbyte < len)
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endbyte = -1;
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else
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endbyte--; /* inclusive */
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bdi = mapping->backing_dev_info;
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switch (advice) {
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case POSIX_FADV_NORMAL:
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file->f_ra.ra_pages = bdi->ra_pages;
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break;
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case POSIX_FADV_RANDOM:
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file->f_ra.ra_pages = 0;
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break;
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case POSIX_FADV_SEQUENTIAL:
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file->f_ra.ra_pages = bdi->ra_pages * 2;
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break;
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case POSIX_FADV_WILLNEED:
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if (!mapping->a_ops->readpage) {
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ret = -EINVAL;
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break;
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}
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/* First and last PARTIAL page! */
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start_index = offset >> PAGE_CACHE_SHIFT;
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end_index = endbyte >> PAGE_CACHE_SHIFT;
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/* Careful about overflow on the "+1" */
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nrpages = end_index - start_index + 1;
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if (!nrpages)
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nrpages = ~0UL;
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ret = force_page_cache_readahead(mapping, file,
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start_index,
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max_sane_readahead(nrpages));
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if (ret > 0)
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ret = 0;
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break;
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case POSIX_FADV_NOREUSE:
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break;
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case POSIX_FADV_DONTNEED:
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if (!bdi_write_congested(mapping->backing_dev_info))
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filemap_flush(mapping);
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/* First and last FULL page! */
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start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
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end_index = (endbyte >> PAGE_CACHE_SHIFT);
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if (end_index >= start_index)
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invalidate_mapping_pages(mapping, start_index,
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end_index);
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break;
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default:
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ret = -EINVAL;
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}
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out:
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fput(file);
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return ret;
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}
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#ifdef __ARCH_WANT_SYS_FADVISE64
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asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
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{
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return sys_fadvise64_64(fd, offset, len, advice);
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}
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#endif
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