Re: [PATCH 3/3] btrfs: Avoid live-lock in search_ioctl() on hardware with sub-page faults
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2021-11-29 15:46:05
Also in:
linux-arm-kernel, linux-fsdevel, lkml
On Sat, Nov 27, 2021 at 07:05:39PM +0100, Andreas Gruenbacher wrote:
quoted hunk ↗ jump to hunk
Maybe you want to add this though:--- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c@@ -2202,3 +2202,3 @@ static noinline int search_ioctl(struct inode *inode, unsigned long sk_offset = 0; - char __user *fault_in_addr; + char __user *fault_in_addr, *end;@@ -2230,6 +2230,6 @@ static noinline int search_ioctl(struct inode *inode, fault_in_addr = ubuf; + end = ubuf + *buf_size; while (1) { ret = -EFAULT; - if (fault_in_writeable(fault_in_addr, - *buf_size - (fault_in_addr - ubuf))) + if (fault_in_writeable(fault_in_addr, end - fault_in_addr)) break;
It looks like *buf_size is updated inside copy_to_sk(), so I'll move the end update inside the loop. -- Catalin