Revert 4fb5ef089b28 ("tmpfs: support SEEK_DATA and SEEK_HOLE").
I believe it's correct, and it's been nice to have from rc1 to rc6;
but as the original commit said:
I don't know who actually uses SEEK_DATA or SEEK_HOLE, and whether it
would be of any use to them on tmpfs. This code adds 92 lines and 752
bytes on x86_64 - is that bloat or worthwhile?
Nobody asked for it, so I conclude that it's bloat: let's revert tmpfs
to the dumb generic support for v3.5. We can always reinstate it later
if useful, and anyone needing it in a hurry can just get it out of git.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Andreas Dilger <adilger@xxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Marco Stornelli <marco.stornelli@xxxxxxxxx>
Cc: Jeff liu <jeff.liu@xxxxxxxxxx>
Cc: Chris Mason <chris.mason@xxxxxxxxxxxx>
---
But if someone protests at this reversion, of course we can drop it.
mm/shmem.c | 94 ---------------------------------------------------
1 file changed, 1 insertion(+), 93 deletions(-)
--- 3.5-rc6/mm/shmem.c 2012-07-07 18:20:40.635328642 -0700
+++ linux/mm/shmem.c 2012-07-07 19:20:02.986950655 -0700
@@ -1692,98 +1692,6 @@ static ssize_t shmem_file_splice_read(st
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;
- struct inode *inode;
- 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);
- mapping = file->f_mapping;
- inode = mapping->host;
- 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)
{
@@ -2787,7 +2695,7 @@ static const struct address_space_operat
static const struct file_operations shmem_file_operations = {
.mmap = shmem_mmap,
#ifdef CONFIG_TMPFS
- .llseek = shmem_file_llseek,
+ .llseek = generic_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = shmem_file_aio_read,
--
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