[Devel] [PATCH RHEL8 COMMIT] net/sock: teach sock_kmalloc() to call kvmalloc() when possible

[Konstantin Khorenko]

The commit is pushed to "branch-rh8-4.18.0-240.1.1.vz8.5.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-240.1.1.vz8.5.34
------>
commit 3b77a0fd64177e3f8b7ba3f8c11e94a776378925
Author: Konstantin Khorenko <khorenko at virtuozzo.com>
Date:   Wed Jun 2 13:26:01 2021 +0300

    net/sock: teach sock_kmalloc() to call kvmalloc() when possible
    
    sock_setsockopt()
     sk_attach_filter()
      sock_kmalloc()
    
    Memory size to be allocated depends on the number of rules provided by
    userspace, but not more than net.core.optmem_max (20480 by default),
    which still allows to allocate 3rd order pages via kmalloc() =>
    it's better to substitute it with kvmalloc().
    
    But sock_kmalloc() can be called with GFP_ATOMIC from some places,
    so we cannot unconditionally call kvmalloc() instead of kmalloc().
    
    Hopefully sk_attach_filter() calls sock_kmalloc() with GFP_KERNEL,
    so kvmalloc() can be used there.
    
    => use kvmalloc_check() which calls kvmalloc() if it's allowed
    by provided flags.
    
    https://jira.sw.ru/browse/PSBM-82593
    
    Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
    
    Ughh, but ok.
    Reviewed-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
    
    (cherry picked from vz7 commit 29b736c18d06 ("net/sock: teach sock_kmalloc() to
    call kvmalloc() when possible"))
    
    VZ 8 rebase part https://jira.sw.ru/browse/PSBM-127798
    
    Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn at virtuozzo.com>
---
 net/core/sock.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index 18b8908d200a..03ad9fbb2906 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2107,7 +2107,7 @@ void *sock_kmalloc(struct sock *sk, int size, gfp_t priority)
 		 * might sleep.
 		 */
 		atomic_add(size, &sk->sk_omem_alloc);
-		mem = kmalloc(size, priority);
+		mem = kvmalloc_check(size, priority);
 		if (mem)
 			return mem;
 		atomic_sub(size, &sk->sk_omem_alloc);
@@ -2126,9 +2126,9 @@ static inline void __sock_kfree_s(struct sock *sk, void *mem, int size,
 	if (WARN_ON_ONCE(!mem))
 		return;
 	if (nullify)
-		kzfree(mem);
-	else
-		kfree(mem);
+		memset(mem, 0, size);
+
+	kvfree(mem);
 	atomic_sub(size, &sk->sk_omem_alloc);
 }