From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0B8392EEE61 for ; Wed, 7 Oct 2026 00:51:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791334272; cv=none; b=rPiN8ZAjrirwEnhU3mZeBky+gUZT/j3vs3zzqhZEVRfx1HTV3qU4Ms7RTWEjliOHzUe1bqdNQfCb2piUXAvWHa/3BJhi3HdeOAE1bUG5bcWTzb95YlfTTIH31DffMrOFbsJ8z63M+DPqzZE7qaspzEnOFMj91HN52CtyKwCVb0A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791334272; c=relaxed/simple; bh=4OKh7efvuOhRJHCzqRvQAe77iZMBgoy2GbVeBqqvXXw=; h=Date:To:From:Subject:Message-Id; b=cq+NYJATkFr+UFAc9Ai7/Fng38IOE7SXNzbeGveGcAca8W1Y6UCJyVbrxu7fiH5Im586teP+FbqIGOEwl9mfQnuttm1NlcPS2LL9v6GIOnidf0vx4ZGgHj+5izr+Xf7orUGywS/1Jbt+X5ku71EQIELGv3k2l69KgAxOgGYZC3U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=nJawqAwX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="nJawqAwX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D91291F0089C; Wed, 7 Oct 2026 00:51:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1791334270; bh=4u9YPWMlcaWTOQORj/dRAbYDrnnRXSwF2ik4wtiipo4=; h=Date:To:From:Subject; b=nJawqAwXtY3BhzGDLw52DZG/IO44ZwHzhWBBF5EQbiMPijRRJPxPGmu9lC0KIPW86 CRyxwkiKtckbhfz5seNT/wpYCUlwBrZg1nWiCsOUokji3+U9O8iD76e0mJnkzkFeUJ 8dhDWn63jtTpB2NEKFUd20n1u1o54SWH1HnEAkTs= Date: Tue, 06 Oct 2026 17:51:10 -0700 To: mm-commits@vger.kernel.org,vbabka@kernel.org,tkjos@android.com,syzbot@syzkaller.appspotmail.com,surenb@google.com,shakeel.butt@linux.dev,ljs@kernel.org,liam@infradead.org,gregkh@linuxfoundation.org,dsahern@kernel.org,david@kernel.org,davem@davemloft.net,cmllamas@google.com,christian@brauner.io,arve@android.com,aliceryhl@google.com,dave.hansen@linux.intel.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] tcp-remove-mmap_lock-fallback-path.patch removed from -mm tree Message-Id: <20261007005110.D91291F0089C@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: tcp: remove mmap_lock fallback path has been removed from the -mm tree. Its filename was tcp-remove-mmap_lock-fallback-path.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Dave Hansen Subject: tcp: remove mmap_lock fallback path Date: Mon, 31 Aug 2026 13:30:56 -0700 Previously, the per-VMA locking could fail in the face of writers which necessitates a fallback to mmap_lock. The new vma_start_read_unlocked() will wait for writers instead of failing. Use the new helper. Wait for writers. Remove the fallback to mmap_lock. The fallback removal does not affect NOMMU case because TCP_ZEROCOPY is gated on CONFIG_MMU. This really is a nice cleanup. It removes the need to pass the lock state back and forth to find_tcp_vma(). Link: https://lore.kernel.org/20260831203056.838265-6-surenb@google.com Signed-off-by: Dave Hansen Signed-off-by: Suren Baghdasaryan Signed-off-by: Andrew Morton Acked-by: Lorenzo Stoakes Acked-by: Vlastimil Babka (SUSE) Tested-by: syzbot@syzkaller.appspotmail.com Cc: Liam R. Howlett Cc: Shakeel Butt Cc: Greg Kroah-Hartman Cc: Arve Hjønnevåg Cc: Todd Kjos Cc: Christian Brauner Cc: Carlos Llamas Cc: Alice Ryhl Cc: David S. Miller Cc: David Ahern Cc: David Hildenbrand (Arm) --- net/ipv4/tcp.c | 31 +++++++++---------------------- 1 file changed, 9 insertions(+), 22 deletions(-) --- a/net/ipv4/tcp.c~tcp-remove-mmap_lock-fallback-path +++ a/net/ipv4/tcp.c @@ -2167,27 +2167,18 @@ static void tcp_zc_finalize_rx_tstamp(st } static struct vm_area_struct *find_tcp_vma(struct mm_struct *mm, - unsigned long address, - bool *mmap_locked) + unsigned long address) { - struct vm_area_struct *vma = lock_vma_under_rcu(mm, address); + struct vm_area_struct *vma = vma_start_read_unlocked(mm, address); - if (vma) { - if (vma->vm_ops != &tcp_vm_ops) { - vma_end_read(vma); - return NULL; - } - *mmap_locked = false; - return vma; - } + if (!vma) + return NULL; - mmap_read_lock(mm); - vma = vma_lookup(mm, address); - if (!vma || vma->vm_ops != &tcp_vm_ops) { - mmap_read_unlock(mm); + if (vma->vm_ops != &tcp_vm_ops) { + vma_end_read(vma); return NULL; } - *mmap_locked = true; + return vma; } @@ -2208,7 +2199,6 @@ static int tcp_zerocopy_receive(struct s u32 seq = tp->copied_seq; u32 total_bytes_to_map; int inq = tcp_inq(sk); - bool mmap_locked; int ret; zc->copybuf_len = 0; @@ -2233,7 +2223,7 @@ static int tcp_zerocopy_receive(struct s return 0; } - vma = find_tcp_vma(current->mm, address, &mmap_locked); + vma = find_tcp_vma(current->mm, address); if (!vma) return -EINVAL; @@ -2315,10 +2305,7 @@ static int tcp_zerocopy_receive(struct s zc, total_bytes_to_map); } out: - if (mmap_locked) - mmap_read_unlock(current->mm); - else - vma_end_read(vma); + vma_end_read(vma); /* Try to copy straggler data. */ if (!ret) copylen = tcp_zc_handle_leftover(zc, sk, skb, &seq, copybuf_len, tss); _ Patches currently in -mm which might be from dave.hansen@linux.intel.com are