[PATCH v3 6/6] Revert "fanotify: disable readahead if we have pre-content watches"

[Amir Goldstein <amir73il@gmail.com>]

This reverts commit fac84846a28c0950d4433118b3dffd44306df62d.
---
 mm/filemap.c   | 12 ------------
 mm/readahead.c | 14 --------------
 2 files changed, 26 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index ff5fcdd961364..6d616bb9001eb 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3197,14 +3197,6 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf)
 	unsigned long vm_flags = vmf->vma->vm_flags;
 	unsigned int mmap_miss;
 
-	/*
-	 * If we have pre-content watches we need to disable readahead to make
-	 * sure that we don't populate our mapping with 0 filled pages that we
-	 * never emitted an event for.
-	 */
-	if (unlikely(FMODE_FSNOTIFY_HSM(file->f_mode)))
-		return fpin;
-
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	/* Use the readahead code, even if readahead is disabled */
 	if ((vm_flags & VM_HUGEPAGE) && HPAGE_PMD_ORDER <= MAX_PAGECACHE_ORDER) {
@@ -3273,10 +3265,6 @@ static struct file *do_async_mmap_readahead(struct vm_fault *vmf,
 	struct file *fpin = NULL;
 	unsigned int mmap_miss;
 
-	/* See comment in do_sync_mmap_readahead. */
-	if (unlikely(FMODE_FSNOTIFY_HSM(file->f_mode)))
-		return fpin;
-
 	/* If we don't want any read-ahead, don't bother */
 	if (vmf->vma->vm_flags & VM_RAND_READ || !ra->ra_pages)
 		return fpin;
diff --git a/mm/readahead.c b/mm/readahead.c
index 220155a5c9646..6a4e96b69702b 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -128,7 +128,6 @@
 #include <linux/blk-cgroup.h>
 #include <linux/fadvise.h>
 #include <linux/sched/mm.h>
-#include <linux/fsnotify.h>
 
 #include "internal.h"
 
@@ -558,15 +557,6 @@ void page_cache_sync_ra(struct readahead_control *ractl,
 	unsigned long max_pages, contig_count;
 	pgoff_t prev_index, miss;
 
-	/*
-	 * If we have pre-content watches we need to disable readahead to make
-	 * sure that we don't find 0 filled pages in cache that we never emitted
-	 * events for. Filesystems supporting HSM must make sure to not call
-	 * this function with ractl->file unset for files handled by HSM.
-	 */
-	if (ractl->file && unlikely(FMODE_FSNOTIFY_HSM(ractl->file->f_mode)))
-		return;
-
 	/*
 	 * Even if readahead is disabled, issue this request as readahead
 	 * as we'll need it to satisfy the requested range. The forced
@@ -645,10 +635,6 @@ void page_cache_async_ra(struct readahead_control *ractl,
 	if (!ra->ra_pages)
 		return;
 
-	/* See the comment in page_cache_sync_ra. */
-	if (ractl->file && unlikely(FMODE_FSNOTIFY_HSM(ractl->file->f_mode)))
-		return;
-
 	/*
 	 * Same bit is used for PG_readahead and PG_reclaim.
 	 */
-- 
2.34.1