2 files changed, 26 insertions, 1 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 11ccde65c4cf..bfa7d20e6646 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -621,6 +621,7 @@ enum sock_flags {
         SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
         SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
         SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
+        SOCK_MEMALLOC, /* VM depends on this socket for swapping */
         SOCK_TIMESTAMPING_TX_HARDWARE,  /* %SOF_TIMESTAMPING_TX_HARDWARE */
         SOCK_TIMESTAMPING_TX_SOFTWARE,  /* %SOF_TIMESTAMPING_TX_SOFTWARE */
         SOCK_TIMESTAMPING_RX_HARDWARE,  /* %SOF_TIMESTAMPING_RX_HARDWARE */
@@ -660,7 +661,7 @@ static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
 
 static inline gfp_t sk_gfp_atomic(struct sock *sk, gfp_t gfp_mask)
 {
-        return GFP_ATOMIC;
+        return GFP_ATOMIC | (sk->sk_allocation & __GFP_MEMALLOC);
 }
 
 static inline void sk_acceptq_removed(struct sock *sk)
@@ -803,6 +804,8 @@ extern int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
 extern void sk_stream_wait_close(struct sock *sk, long timeo_p);
 extern int sk_stream_error(struct sock *sk, int flags, int err);
 extern void sk_stream_kill_queues(struct sock *sk);
+extern void sk_set_memalloc(struct sock *sk);
+extern void sk_clear_memalloc(struct sock *sk);
 
 extern int sk_wait_data(struct sock *sk, long *timeo);
 
diff --git a/net/core/sock.c b/net/core/sock.c
index a67b06280e4c..3617f652f6b0 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -271,6 +271,28 @@ __u32 sysctl_rmem_default __read_mostly = SK_RMEM_MAX;
 int sysctl_optmem_max __read_mostly = sizeof(unsigned long)*(2*UIO_MAXIOV+512);
 EXPORT_SYMBOL(sysctl_optmem_max);
 
+/**
+ * sk_set_memalloc - sets %SOCK_MEMALLOC
+ * @sk: socket to set it on
+ *
+ * Set %SOCK_MEMALLOC on a socket for access to emergency reserves.
+ * It's the responsibility of the admin to adjust min_free_kbytes
+ * to meet the requirements
+ */
+void sk_set_memalloc(struct sock *sk)
+{
+        sock_set_flag(sk, SOCK_MEMALLOC);
+        sk->sk_allocation |= __GFP_MEMALLOC;
+}
+EXPORT_SYMBOL_GPL(sk_set_memalloc);
+
+void sk_clear_memalloc(struct sock *sk)
+{
+        sock_reset_flag(sk, SOCK_MEMALLOC);
+        sk->sk_allocation &= ~__GFP_MEMALLOC;
+}
+EXPORT_SYMBOL_GPL(sk_clear_memalloc);
+
 #if defined(CONFIG_CGROUPS)
 #if !defined(CONFIG_NET_CLS_CGROUP)
 int net_cls_subsys_id = -1;