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authorMatthew Wilcox (Oracle) <willy@infradead.org>2023-07-24 19:54:02 +0100
committerAndrew Morton <akpm@linux-foundation.org>2023-08-18 10:12:51 -0700
commit350f6bbca1de515cd7519a33661cefc93ea06054 (patch)
tree097b836f7ea8c5145eae8c2c37dcee42591d148a /net/ipv4
parent284e05920498788c5df1a7dd6424adb426498e1c (diff)
mm: allow per-VMA locks on file-backed VMAs
Remove the TCP layering violation by allowing per-VMA locks on all VMAs. The fault path will immediately fail in handle_mm_fault(). There may be a small performance reduction from this patch as a little unnecessary work will be done on each page fault. See later patches for the improvement. Link: https://lkml.kernel.org/r/20230724185410.1124082-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8ed52e1e3c99..b9d49803e77f 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1739,7 +1739,7 @@ void tcp_update_recv_tstamps(struct sk_buff *skb,
}
#ifdef CONFIG_MMU
-const struct vm_operations_struct tcp_vm_ops = {
+static const struct vm_operations_struct tcp_vm_ops = {
};
int tcp_mmap(struct file *file, struct socket *sock,
@@ -2042,13 +2042,10 @@ static struct vm_area_struct *find_tcp_vma(struct mm_struct *mm,
unsigned long address,
bool *mmap_locked)
{
- struct vm_area_struct *vma = NULL;
+ struct vm_area_struct *vma = lock_vma_under_rcu(mm, address);
-#ifdef CONFIG_PER_VMA_LOCK
- vma = lock_vma_under_rcu(mm, address);
-#endif
if (vma) {
- if (!vma_is_tcp(vma)) {
+ if (vma->vm_ops != &tcp_vm_ops) {
vma_end_read(vma);
return NULL;
}
@@ -2058,7 +2055,7 @@ static struct vm_area_struct *find_tcp_vma(struct mm_struct *mm,
mmap_read_lock(mm);
vma = vma_lookup(mm, address);
- if (!vma || !vma_is_tcp(vma)) {
+ if (!vma || vma->vm_ops != &tcp_vm_ops) {
mmap_read_unlock(mm);
return NULL;
}