From: Catalin Marinas <catalin.marinas@arm.com>
To: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
"Darrick J. Wong" <djwong@kernel.org>,
Paul Mackerras <paulus@ozlabs.org>, Jan Kara <jack@suse.cz>,
Matthew Wilcox <willy@infradead.org>,
cluster-devel@redhat.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com,
kvm-ppc@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v8 05/17] iov_iter: Introduce fault_in_iov_iter_writeable
Date: Wed, 20 Oct 2021 17:25:24 +0100 [thread overview]
Message-ID: <YXBC9LRwhgFCHqJA@arm.com> (raw)
In-Reply-To: <20211019134204.3382645-6-agruenba@redhat.com>
On Tue, Oct 19, 2021 at 03:41:52PM +0200, Andreas Gruenbacher wrote:
> diff --git a/mm/gup.c b/mm/gup.c
> index a7efb027d6cf..614b8536b3b6 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1691,6 +1691,69 @@ size_t fault_in_writeable(char __user *uaddr, size_t size)
> }
> EXPORT_SYMBOL(fault_in_writeable);
>
> +/*
> + * fault_in_safe_writeable - fault in an address range for writing
> + * @uaddr: start of address range
> + * @size: length of address range
> + *
> + * Faults in an address range using get_user_pages, i.e., without triggering
> + * hardware page faults. This is primarily useful when we already know that
> + * some or all of the pages in the address range aren't in memory.
> + *
> + * Other than fault_in_writeable(), this function is non-destructive.
> + *
> + * Note that we don't pin or otherwise hold the pages referenced that we fault
> + * in. There's no guarantee that they'll stay in memory for any duration of
> + * time.
> + *
> + * Returns the number of bytes not faulted in, like copy_to_user() and
> + * copy_from_user().
> + */
> +size_t fault_in_safe_writeable(const char __user *uaddr, size_t size)
> +{
> + unsigned long start = (unsigned long)uaddr;
> + unsigned long end, nstart, nend;
> + struct mm_struct *mm = current->mm;
> + struct vm_area_struct *vma = NULL;
For arm64 tagged addresses we need the diff below, otherwise the
subsequent find_vma() will fail:
diff --git a/mm/gup.c b/mm/gup.c
index f5f362cb4640..2c51e9748a6a 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1713,7 +1713,7 @@ EXPORT_SYMBOL(fault_in_writeable);
*/
size_t fault_in_safe_writeable(const char __user *uaddr, size_t size)
{
- unsigned long start = (unsigned long)uaddr;
+ unsigned long start = (unsigned long)untagged_addr(uaddr);
unsigned long end, nstart, nend;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma = NULL;
--
Catalin
next prev parent reply other threads:[~2021-10-20 16:25 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 13:41 [PATCH v8 00/17] gfs2: Fix mmap + page fault deadlocks Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 01/17] iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 02/17] powerpc/kvm: Fix kvm_use_magic_page Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 03/17] gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable} Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 04/17] iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 05/17] iov_iter: Introduce fault_in_iov_iter_writeable Andreas Gruenbacher
2021-10-20 16:25 ` Catalin Marinas [this message]
2021-10-19 13:41 ` [PATCH v8 06/17] gfs2: Add wrapper for iomap_file_buffered_write Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 07/17] gfs2: Clean up function may_grant Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 08/17] gfs2: Introduce flag for glock holder auto-demotion Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 09/17] gfs2: Move the inode glock locking to gfs2_file_buffered_write Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 10/17] gfs2: Eliminate ip->i_gh Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 11/17] gfs2: Fix mmap + page fault deadlocks for buffered I/O Andreas Gruenbacher
2021-10-19 13:41 ` [PATCH v8 12/17] iomap: Fix iomap_dio_rw return value for user copies Andreas Gruenbacher
2021-10-19 13:42 ` [PATCH v8 13/17] iomap: Support partial direct I/O on user copy failures Andreas Gruenbacher
2021-10-19 13:42 ` [PATCH v8 14/17] iomap: Add done_before argument to iomap_dio_rw Andreas Gruenbacher
2021-10-19 15:51 ` Darrick J. Wong
2021-10-19 19:30 ` Andreas Gruenbacher
2021-10-20 1:57 ` Darrick J. Wong
2021-10-19 13:42 ` [PATCH v8 15/17] gup: Introduce FOLL_NOFAULT flag to disable page faults Andreas Gruenbacher
2021-10-19 13:42 ` [PATCH v8 16/17] iov_iter: Introduce nofault " Andreas Gruenbacher
2021-10-19 13:42 ` [PATCH v8 17/17] gfs2: Fix mmap + page fault deadlocks for direct I/O Andreas Gruenbacher
2021-10-19 15:40 ` [PATCH v8 00/17] gfs2: Fix mmap + page fault deadlocks Linus Torvalds
2021-10-19 16:00 ` Bob Peterson
2021-10-20 16:36 ` Catalin Marinas
2021-10-20 20:11 ` Linus Torvalds
2021-10-20 22:44 ` Catalin Marinas
2021-10-21 6:19 ` Linus Torvalds
2021-10-22 18:06 ` Catalin Marinas
2021-10-22 19:22 ` Linus Torvalds
2021-10-25 19:00 ` Andreas Gruenbacher
2021-10-26 18:24 ` Catalin Marinas
2021-10-26 18:50 ` Linus Torvalds
2021-10-26 19:18 ` Linus Torvalds
2021-10-27 19:13 ` Catalin Marinas
2021-10-27 21:14 ` Linus Torvalds
2021-10-28 21:20 ` Catalin Marinas
2021-10-28 21:40 ` Catalin Marinas
2021-10-28 22:15 ` Andreas Grünbacher
2021-10-29 12:50 ` Catalin Marinas
2021-10-28 22:32 ` Linus Torvalds
2021-10-29 17:50 ` Catalin Marinas
2021-10-29 18:47 ` Linus Torvalds
2021-10-25 18:24 ` Andreas Gruenbacher
2021-10-26 5:12 ` Theodore Ts'o
2021-10-26 9:44 ` Andreas Gruenbacher
2021-10-27 21:21 ` Andreas Gruenbacher
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