From afe6949862f77bcc14fa16ad7938a04e84586d6a Mon Sep 17 00:00:00 2001 From: Tom Rix Date: Fri, 30 Apr 2021 08:50:31 -0700 Subject: [PATCH] afs: check function return 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 Signed-off-by: David Howells Reviewed-by: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20210430155031.3287870-1-trix@redhat.com Link: https://lore.kernel.org/r/CAB9dFdvHsLsw7CMnB+4cgciWDSqVjuij4mH3TaXnHQB8sz5rHw@mail.gmail.com/ [1] Link: https://lore.kernel.org/r/162609464716.3133237.10354897554363093252.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162610727640.3408253.8687445613469681311.stgit@warthog.procyon.org.uk/ # v2 --- 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, -- 2.34.1