[PATCH 5.16 144/285] NFS: Avoid writeback threads getting stuck in mempool_alloc()

Greg Kroah-Hartman
2022-04-12T08:37:59Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit 0bae835b63c53f86cdc524f5962e39409585b22c ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfs/pagelist.c | 10 +++++-----
fs/nfs/write.c | 10 ++++++++--
2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 815d63080245..9157dd19b8b4 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -90,10 +90,10 @@ void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
}
}

-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;
@@ -892,7 +892,7 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
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;
@@ -979,7 +979,7 @@ nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
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);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 8eb7466182ac..fdaca2a55f36 100644
--- 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;
}
--
2.35.1