summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--include/linux/shmem_fs.h1
-rw-r--r--mm/khugepaged.c2
-rw-r--r--mm/shmem.c29
3 files changed, 19 insertions, 13 deletions
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index bfc5899d18e0..a3f4502ec8a9 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -94,6 +94,7 @@ extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
/* Flag allocation requirements to shmem_getpage */
enum sgp_type {
SGP_READ, /* don't exceed i_size, don't allocate page */
+ SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
SGP_CACHE, /* don't exceed i_size, may allocate page */
SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index b0412be08fa2..045cc579f724 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1721,7 +1721,7 @@ static void collapse_file(struct mm_struct *mm,
xas_unlock_irq(&xas);
/* swap in or instantiate fallocated page */
if (shmem_getpage(mapping->host, index, &page,
- SGP_NOHUGE)) {
+ SGP_NOALLOC)) {
result = SCAN_FAIL;
goto xa_unlocked;
}
diff --git a/mm/shmem.c b/mm/shmem.c
index 2df6a5370cd7..867cb404090a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1854,26 +1854,31 @@ repeat:
return error;
}
- if (page)
+ if (page) {
hindex = page->index;
- if (page && sgp == SGP_WRITE)
- mark_page_accessed(page);
-
- /* fallocated page? */
- if (page && !PageUptodate(page)) {
+ if (sgp == SGP_WRITE)
+ mark_page_accessed(page);
+ if (PageUptodate(page))
+ goto out;
+ /* fallocated page */
if (sgp != SGP_READ)
goto clear;
unlock_page(page);
put_page(page);
- page = NULL;
- hindex = index;
}
- if (page || sgp == SGP_READ)
- goto out;
/*
- * Fast cache lookup did not find it:
- * bring it back from swap or allocate.
+ * SGP_READ: succeed on hole, with NULL page, letting caller zero.
+ * SGP_NOALLOC: fail on hole, with NULL page, letting caller fail.
+ */
+ *pagep = NULL;
+ if (sgp == SGP_READ)
+ return 0;
+ if (sgp == SGP_NOALLOC)
+ return -ENOENT;
+
+ /*
+ * Fast cache lookup and swap lookup did not find it: allocate.
*/
if (vma && userfaultfd_missing(vma)) {