treewide: Remove uninitialized_var() usage

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>

6 files changed, 6 insertions, 6 deletions

diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 81ffc59d05c9..4312007d2d34 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -306,7 +306,7 @@ static void do_region(int op, int op_flags, unsigned region,
 	struct request_queue *q = bdev_get_queue(where->bdev);
 	unsigned short logical_block_size = queue_logical_block_size(q);
 	sector_t num_sectors;
-	unsigned int uninitialized_var(special_cmd_max_sectors);
+	unsigned int special_cmd_max_sectors;
 
 	/*
 	 * Reject unsupported discard and write same requests.
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 489935d5f22d..056d891a32a9 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1844,7 +1844,7 @@ static int ctl_ioctl(struct file *file, uint command, struct dm_ioctl __user *us
 	int ioctl_flags;
 	int param_flags;
 	unsigned int cmd;
-	struct dm_ioctl *uninitialized_var(param);
+	struct dm_ioctl *param;
 	ioctl_fn fn = NULL;
 	size_t input_param_size;
 	struct dm_ioctl param_kernel;
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 963d3774c93e..247089c2be25 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -613,7 +613,7 @@ static int persistent_read_metadata(struct dm_exception_store *store,
 						    chunk_t old, chunk_t new),
 				    void *callback_context)
 {
-	int r, uninitialized_var(new_snapshot);
+	int r, new_snapshot;
 	struct pstore *ps = get_info(store);
 
 	/*
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 8277b959e00b..89d7cda07640 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -642,7 +642,7 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table,
 	 */
 	unsigned short remaining = 0;
 
-	struct dm_target *uninitialized_var(ti);
+	struct dm_target *ti;
 	struct queue_limits ti_limits;
 	unsigned i;
 
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 30505d70f423..ec83edff25bf 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1752,7 +1752,7 @@ static void writecache_writeback(struct work_struct *work)
 {
 	struct dm_writecache *wc = container_of(work, struct dm_writecache, writeback_work);
 	struct blk_plug plug;
-	struct wc_entry *f, *uninitialized_var(g), *e = NULL;
+	struct wc_entry *f, *g, *e = NULL;
 	struct rb_node *node, *next_node;
 	struct list_head skipped;
 	struct writeback_list wbl;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ab8067f9ce8c..401b366af076 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2601,7 +2601,7 @@ static void raid5_end_write_request(struct bio *bi)
 	struct stripe_head *sh = bi->bi_private;
 	struct r5conf *conf = sh->raid_conf;
 	int disks = sh->disks, i;
-	struct md_rdev *uninitialized_var(rdev);
+	struct md_rdev *rdev;
 	sector_t first_bad;
 	int bad_sectors;
 	int replacement = 0;