Evolution-X-Devices/kernel_xiaomi_sm8150
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Revert "BACKPORT: FROMLIST: mm: implement speculative handling in filemap_fault()"

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This reverts commit 9debe341d5.

Change-Id: I3197cb64766cd5e102794d24c946bb88a8e73652
Signed-off-by: Alexander Winkowski <dereference23@outlook.com>
This commit is contained in:
Alexander Winkowski
2024-01-12 04:59:40 +00:00
committed by basamaryan
parent 873a2dc3e7
commit 440e1675ca
1 changed files with 1 additions and 44 deletions
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45
mm/filemap.c
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@@ -2474,9 +2474,7 @@ static struct file *do_async_mmap_readahead(struct vm_fault *vmf,
* it in the page cache, and handles the special cases reasonably without
* having a lot of duplicated code.
*
* If FAULT_FLAG_SPECULATIVE is set, this function runs with elevated vma
* refcount and with mmap lock not held.
* Otherwise, vma->vm_mm->mmap_sem must be held on entry.
* vma->vm_mm->mmap_sem must be held on entry.
*
* If our return value has VM_FAULT_RETRY set, it's because
* lock_page_or_retry() returned 0.
@@ -2501,47 +2499,6 @@ int filemap_fault(struct vm_fault *vmf)
struct page *page;
int ret = 0;
if (vmf->flags & FAULT_FLAG_SPECULATIVE) {
page = find_get_page(mapping, offset);
if (unlikely(!page) || unlikely(PageReadahead(page)))
return VM_FAULT_RETRY;
if (!trylock_page(page))
return VM_FAULT_RETRY;
if (unlikely(compound_head(page)->mapping != mapping))
goto page_unlock;
VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page);
if (unlikely(!PageUptodate(page)))
goto page_unlock;
max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
if (unlikely(offset >= max_off))
goto page_unlock;
/*
* Update readahead mmap_miss statistic.
*
* Note that we are not sure if finish_fault() will
* manage to complete the transaction. If it fails,
* we'll come back to filemap_fault() non-speculative
* case which will update mmap_miss a second time.
* This is not ideal, we would prefer to guarantee the
* update will happen exactly once.
*/
if (!(vmf->vma->vm_flags & VM_RAND_READ) && ra->ra_pages) {
unsigned int mmap_miss = READ_ONCE(ra->mmap_miss);
if (mmap_miss)
WRITE_ONCE(ra->mmap_miss, --mmap_miss);
}
vmf->page = page;
return VM_FAULT_LOCKED;
page_unlock:
unlock_page(page);
return VM_FAULT_RETRY;
}
max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
if (unlikely(offset >= max_off))
return VM_FAULT_SIGBUS;