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>

4 files changed, 8 insertions, 8 deletions

diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
index 896d74cb5081..1b10717c9321 100644
--- a/arch/x86/kernel/quirks.c
+++ b/arch/x86/kernel/quirks.c
@@ -95,7 +95,7 @@ static void ich_force_hpet_resume(void)
 static void ich_force_enable_hpet(struct pci_dev *dev)
 {
 	u32 val;
-	u32 uninitialized_var(rcba);
+	u32 rcba;
 	int err = 0;
 
 	if (hpet_address || force_hpet_address)
@@ -185,7 +185,7 @@ static void hpet_print_force_info(void)
 static void old_ich_force_hpet_resume(void)
 {
 	u32 val;
-	u32 uninitialized_var(gen_cntl);
+	u32 gen_cntl;
 
 	if (!force_hpet_address || !cached_dev)
 		return;
@@ -207,7 +207,7 @@ static void old_ich_force_hpet_resume(void)
 static void old_ich_force_enable_hpet(struct pci_dev *dev)
 {
 	u32 val;
-	u32 uninitialized_var(gen_cntl);
+	u32 gen_cntl;
 
 	if (hpet_address || force_hpet_address)
 		return;
@@ -298,7 +298,7 @@ static void vt8237_force_hpet_resume(void)
 
 static void vt8237_force_enable_hpet(struct pci_dev *dev)
 {
-	u32 uninitialized_var(val);
+	u32 val;
 
 	if (hpet_address || force_hpet_address)
 		return;
@@ -429,7 +429,7 @@ static void nvidia_force_hpet_resume(void)
 
 static void nvidia_force_enable_hpet(struct pci_dev *dev)
 {
-	u32 uninitialized_var(val);
+	u32 val;
 
 	if (hpet_address || force_hpet_address)
 		return;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 76817d13c86e..deafcced65d2 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1986,7 +1986,7 @@ static int kvm_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
 			 unsigned long data)
 {
 	u64 *sptep;
-	struct rmap_iterator uninitialized_var(iter);
+	struct rmap_iterator iter;
 	int young = 0;
 
 	for_each_rmap_spte(rmap_head, &iter, sptep)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index bd70ece1ef8b..275564a0ebdb 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -314,7 +314,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
 {
 	int ret;
 	pt_element_t pte;
-	pt_element_t __user *uninitialized_var(ptep_user);
+	pt_element_t __user *ptep_user;
 	gfn_t table_gfn;
 	u64 pt_access, pte_access;
 	unsigned index, accessed_dirty, pte_pkey;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3b92db412335..598d5be960c9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9927,7 +9927,7 @@ void kvm_arch_sync_events(struct kvm *kvm)
 int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size)
 {
 	int i, r;
-	unsigned long hva, uninitialized_var(old_npages);
+	unsigned long hva, old_npages;
 	struct kvm_memslots *slots = kvm_memslots(kvm);
 	struct kvm_memory_slot *slot;