From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Mon, 21 Mar 2022 13:48:36 -0400
Subject: [PATCH] NFS: Avoid writeback threads getting stuck in mempool_alloc()
Git-commit: 0bae835b63c53f86cdc524f5962e39409585b22c
Patch-mainline: v5.18
References: git-fixes
In a low memory situation, allow the NFS writeback code to fail without
getting stuck in infinite loops in mempool_alloc().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: NeilBrown <neilb@suse.com>
---
fs/nfs/pagelist.c | 10 +++++-----
fs/nfs/write.c | 10 ++++++++--
2 files changed, 13 insertions(+), 7 deletions(-)
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -90,10 +90,10 @@ void nfs_set_pgio_error(struct nfs_pgio_
}
}
-static inline struct nfs_page *
-nfs_page_alloc(void)
+static inline struct nfs_page *nfs_page_alloc(void)
{
- struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL);
+ struct nfs_page *p =
+ kmem_cache_zalloc(nfs_page_cachep, nfs_io_gfp_mask());
if (p)
INIT_LIST_HEAD(&p->wb_list);
return p;
@@ -904,7 +904,7 @@ int nfs_generic_pgio(struct nfs_pageio_d
struct nfs_commit_info cinfo;
struct nfs_page_array *pg_array = &hdr->page_array;
unsigned int pagecount, pageused;
- gfp_t gfp_flags = GFP_KERNEL;
+ gfp_t gfp_flags = nfs_io_gfp_mask();
pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
pg_array->npages = pagecount;
@@ -991,7 +991,7 @@ nfs_pageio_alloc_mirrors(struct nfs_page
desc->pg_mirrors_dynamic = NULL;
if (mirror_count == 1)
return desc->pg_mirrors_static;
- ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_KERNEL);
+ ret = kmalloc_array(mirror_count, sizeof(*ret), nfs_io_gfp_mask());
if (ret != NULL) {
for (i = 0; i < mirror_count; i++)
nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -94,9 +94,15 @@ EXPORT_SYMBOL_GPL(nfs_commit_free);
static struct nfs_pgio_header *nfs_writehdr_alloc(void)
{
- struct nfs_pgio_header *p = mempool_alloc(nfs_wdata_mempool, GFP_KERNEL);
+ struct nfs_pgio_header *p;
- memset(p, 0, sizeof(*p));
+ p = kmem_cache_zalloc(nfs_wdata_cachep, nfs_io_gfp_mask());
+ if (!p) {
+ p = mempool_alloc(nfs_wdata_mempool, GFP_NOWAIT);
+ if (!p)
+ return NULL;
+ memset(p, 0, sizeof(*p));
+ }
p->rw_mode = FMODE_WRITE;
return p;
}