lkml.org 
[lkml]   [2021]   [Jul]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v2 2/4] afs: check function return
On Mon, Jul 12, 2021 at 1:28 PM David Howells <dhowells@redhat.com> wrote:
>
> From: Tom Rix <trix@redhat.com>
>
> Static analysis reports this problem
>
> write.c:773:29: warning: Assigned value is garbage or undefined
> mapping->writeback_index = next;
> ^ ~~~~
> The call to afs_writepages_region() can return without setting
> next. So check the function return before using next.
>
> Changes:
> ver #2:
> - Need to fix the range_cyclic case also[1].
>
> Fixes: e87b03f5830e ("afs: Prepare for use of THPs")
> Signed-off-by: Tom Rix <trix@redhat.com>
> Signed-off-by: David Howells <dhowells@redhat.com>
> Link: https://lore.kernel.org/r/20210430155031.3287870-1-trix@redhat.com
> Link: https://lore.kernel.org/r/162609464716.3133237.10354897554363093252.stgit@warthog.procyon.org.uk/ # v1
> Link: https://lore.kernel.org/r/CAB9dFdvHsLsw7CMnB+4cgciWDSqVjuij4mH3TaXnHQB8sz5rHw@mail.gmail.com/ [1]
> ---
>
> fs/afs/write.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/fs/afs/write.c b/fs/afs/write.c
> index 3104b62c2082..1ed62e0ccfe5 100644
> --- a/fs/afs/write.c
> +++ b/fs/afs/write.c
> @@ -771,13 +771,19 @@ int afs_writepages(struct address_space *mapping,
> if (wbc->range_cyclic) {
> start = mapping->writeback_index * PAGE_SIZE;
> ret = afs_writepages_region(mapping, wbc, start, LLONG_MAX, &next);
> - if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
> - ret = afs_writepages_region(mapping, wbc, 0, start,
> - &next);
> - mapping->writeback_index = next / PAGE_SIZE;
> + if (ret == 0) {
> + mapping->writeback_index = next / PAGE_SIZE;
> + if (start > 0 && wbc->nr_to_write > 0) {
> + ret = afs_writepages_region(mapping, wbc, 0,
> + start, &next);
> + if (ret == 0)
> + mapping->writeback_index =
> + next / PAGE_SIZE;
> + }
> + }
> } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
> ret = afs_writepages_region(mapping, wbc, 0, LLONG_MAX, &next);
> - if (wbc->nr_to_write > 0)
> + if (wbc->nr_to_write > 0 && ret == 0)
> mapping->writeback_index = next;
> } else {
> ret = afs_writepages_region(mapping, wbc,
>
>

Reviewed-by: Marc Dionne <marc.dionne@auristor.com>

Marc

\
 
 \ /
  Last update: 2021-07-21 15:00    [W:0.082 / U:0.860 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site