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authorLinus Torvalds <torvalds@linux-foundation.org>2012-12-13 21:11:15 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-13 21:11:15 (GMT)
commitf6e858a00af788bab0fd4c0b7f5cd788000edc18 (patch)
treef9403ca3671be9821dbf83e726e61dbe75fbca6b /mm/shmem.c
parent193c0d682525987db59ac3a24531a77e4947aa95 (diff)
parent98870901cce098bbe94d90d2c41d8d1fa8d94392 (diff)
downloadlinux-f6e858a00af788bab0fd4c0b7f5cd788000edc18.tar.xz
Merge branch 'akpm' (Andrew's patch-bomb)
Merge misc VM changes from Andrew Morton: "The rest of most-of-MM. The other MM bits await a slab merge. This patch includes the addition of a huge zero_page. Not a performance boost but it an save large amounts of physical memory in some situations. Also a bunch of Fujitsu engineers are working on memory hotplug. Which, as it turns out, was badly broken. About half of their patches are included here; the remainder are 3.8 material." However, this merge disables CONFIG_MOVABLE_NODE, which was totally broken. We don't add new features with "default y", nor do we add Kconfig questions that are incomprehensible to most people without any help text. Does the feature even make sense without compaction or memory hotplug? * akpm: (54 commits) mm/bootmem.c: remove unused wrapper function reserve_bootmem_generic() mm/memory.c: remove unused code from do_wp_page() asm-generic, mm: pgtable: consolidate zero page helpers mm/hugetlb.c: fix warning on freeing hwpoisoned hugepage hwpoison, hugetlbfs: fix RSS-counter warning hwpoison, hugetlbfs: fix "bad pmd" warning in unmapping hwpoisoned hugepage mm: protect against concurrent vma expansion memcg: do not check for mm in __mem_cgroup_count_vm_event tmpfs: support SEEK_DATA and SEEK_HOLE (reprise) mm: provide more accurate estimation of pages occupied by memmap fs/buffer.c: remove redundant initialization in alloc_page_buffers() fs/buffer.c: do not inline exported function writeback: fix a typo in comment mm: introduce new field "managed_pages" to struct zone mm, oom: remove statically defined arch functions of same name mm, oom: remove redundant sleep in pagefault oom handler mm, oom: cleanup pagefault oom handler memory_hotplug: allow online/offline memory to result movable node numa: add CONFIG_MOVABLE_NODE for movable-dedicated node mm, memcg: avoid unnecessary function call when memcg is disabled ...
Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c92
1 files changed, 91 insertions, 1 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 50c5b8f..03f9ba8 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1715,6 +1715,96 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
return error;
}
+/*
+ * llseek SEEK_DATA or SEEK_HOLE through the radix_tree.
+ */
+static pgoff_t shmem_seek_hole_data(struct address_space *mapping,
+ pgoff_t index, pgoff_t end, int origin)
+{
+ struct page *page;
+ struct pagevec pvec;
+ pgoff_t indices[PAGEVEC_SIZE];
+ bool done = false;
+ int i;
+
+ pagevec_init(&pvec, 0);
+ pvec.nr = 1; /* start small: we may be there already */
+ while (!done) {
+ pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
+ pvec.nr, pvec.pages, indices);
+ if (!pvec.nr) {
+ if (origin == SEEK_DATA)
+ index = end;
+ break;
+ }
+ for (i = 0; i < pvec.nr; i++, index++) {
+ if (index < indices[i]) {
+ if (origin == SEEK_HOLE) {
+ done = true;
+ break;
+ }
+ index = indices[i];
+ }
+ page = pvec.pages[i];
+ if (page && !radix_tree_exceptional_entry(page)) {
+ if (!PageUptodate(page))
+ page = NULL;
+ }
+ if (index >= end ||
+ (page && origin == SEEK_DATA) ||
+ (!page && origin == SEEK_HOLE)) {
+ done = true;
+ break;
+ }
+ }
+ shmem_deswap_pagevec(&pvec);
+ pagevec_release(&pvec);
+ pvec.nr = PAGEVEC_SIZE;
+ cond_resched();
+ }
+ return index;
+}
+
+static loff_t shmem_file_llseek(struct file *file, loff_t offset, int origin)
+{
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ pgoff_t start, end;
+ loff_t new_offset;
+
+ if (origin != SEEK_DATA && origin != SEEK_HOLE)
+ return generic_file_llseek_size(file, offset, origin,
+ MAX_LFS_FILESIZE, i_size_read(inode));
+ mutex_lock(&inode->i_mutex);
+ /* We're holding i_mutex so we can access i_size directly */
+
+ if (offset < 0)
+ offset = -EINVAL;
+ else if (offset >= inode->i_size)
+ offset = -ENXIO;
+ else {
+ start = offset >> PAGE_CACHE_SHIFT;
+ end = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ new_offset = shmem_seek_hole_data(mapping, start, end, origin);
+ new_offset <<= PAGE_CACHE_SHIFT;
+ if (new_offset > offset) {
+ if (new_offset < inode->i_size)
+ offset = new_offset;
+ else if (origin == SEEK_DATA)
+ offset = -ENXIO;
+ else
+ offset = inode->i_size;
+ }
+ }
+
+ if (offset >= 0 && offset != file->f_pos) {
+ file->f_pos = offset;
+ file->f_version = 0;
+ }
+ mutex_unlock(&inode->i_mutex);
+ return offset;
+}
+
static long shmem_fallocate(struct file *file, int mode, loff_t offset,
loff_t len)
{
@@ -2586,7 +2676,7 @@ static const struct address_space_operations shmem_aops = {
static const struct file_operations shmem_file_operations = {
.mmap = shmem_mmap,
#ifdef CONFIG_TMPFS
- .llseek = generic_file_llseek,
+ .llseek = shmem_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = shmem_file_aio_read,