Merge tag 'fallthrough-pseudo-keyword-5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull 'fallthrough' keyword conversion from Gustavo A. R. Silva:
 "A tree-wide patch that replaces tons (2484) of /* fall through */
  comments, and its variants, with the new pseudo-keyword macro
  fallthrough[1]. Also, remove unnecessary fall-through markings when it
  is the case.

  There are currently 1167 intances of this fallthrough pseudo-keyword
  macro in mainline (5.9-rc2), that have been introduced over the last
  couple of development cycles:

    $ git grep -nw 'fallthrough;' | wc -l
    1167

  The global adoption of the fallthrough pseudo-keyword is something
  certain to happen; so, better sooner than later. :) This will also
  save everybody's time and thousands of lines of unnecessarily
  repetitive changelog text.

  After applying this patch on top of 5.9-rc2, we'll have a total of
  3651 instances of this macro:

    $ git grep -nw 'fallthrough;' | wc -l
    3651

  This treewide patch doesn't address ALL fall-through markings in all
  subsystems at once because I have previously sent out patches for some
  of such subsystems separately, and I will follow up on them; however,
  this definitely contributes most of the work needed to replace all the
  fall-through markings with the fallthrough pseudo-keyword macro in the
  whole codebase.

  I have build-tested this patch on 10 different architectures: x86_64,
  i386, arm64, powerpc, s390, sparc64, sh, m68k, powerpc64 and alpha
  (allyesconfig for all of them). This is in linux-next already and
  kernel test robot has also helped me to successfully build-test early
  versions of this patch[2][3][4][5]"

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through
[2] https://lore.kernel.org/lkml/5f3cc99a.HgvOW3rH0mD0RmkM%25lkp@intel.com/
[3] https://lore.kernel.org/lkml/5f3dd1d2.l1axczH+t4hMBZ63%25lkp@intel.com/
[4] https://lore.kernel.org/lkml/5f3e977a.mwYHUIObbR4SHr0B%25lkp@intel.com/
[5] https://lore.kernel.org/lkml/5f3f9e1c.qsyb%2FaySkiXNpkO4%25lkp@intel.com/

* tag 'fallthrough-pseudo-keyword-5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  treewide: Use fallthrough pseudo-keyword

6 files changed, 35 insertions, 32 deletions

diff --git a/include/linux/compat.h b/include/linux/compat.h
index d38c4d7e83bd..b354ce58966e 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -429,11 +429,11 @@ put_compat_sigset(compat_sigset_t __user *compat, const sigset_t *set,
 	compat_sigset_t v;
 	switch (_NSIG_WORDS) {
 	case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3];
-		/* fall through */
+		fallthrough;
 	case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2];
-		/* fall through */
+		fallthrough;
 	case 2: v.sig[3] = (set->sig[1] >> 32); v.sig[2] = set->sig[1];
-		/* fall through */
+		fallthrough;
 	case 1: v.sig[1] = (set->sig[0] >> 32); v.sig[0] = set->sig[0];
 	}
 	return copy_to_user(compat, &v, size) ? -EFAULT : 0;
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 0a355b005bf4..ebfb7cfb65f1 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1200,7 +1200,7 @@ static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 		BPF_ANCILLARY(RANDOM);
 		BPF_ANCILLARY(VLAN_TPID);
 		}
-		/* Fallthrough. */
+		fallthrough;
 	default:
 		return ftest->code;
 	}
diff --git a/include/linux/jhash.h b/include/linux/jhash.h
index 19ddd43aee68..cfb62e9f37be 100644
--- a/include/linux/jhash.h
+++ b/include/linux/jhash.h
@@ -86,17 +86,17 @@ static inline u32 jhash(const void *key, u32 length, u32 initval)
 	}
 	/* Last block: affect all 32 bits of (c) */
 	switch (length) {
-	case 12: c += (u32)k[11]<<24;	/* fall through */
-	case 11: c += (u32)k[10]<<16;	/* fall through */
-	case 10: c += (u32)k[9]<<8;	/* fall through */
-	case 9:  c += k[8];		/* fall through */
-	case 8:  b += (u32)k[7]<<24;	/* fall through */
-	case 7:  b += (u32)k[6]<<16;	/* fall through */
-	case 6:  b += (u32)k[5]<<8;	/* fall through */
-	case 5:  b += k[4];		/* fall through */
-	case 4:  a += (u32)k[3]<<24;	/* fall through */
-	case 3:  a += (u32)k[2]<<16;	/* fall through */
-	case 2:  a += (u32)k[1]<<8;	/* fall through */
+	case 12: c += (u32)k[11]<<24;	fallthrough;
+	case 11: c += (u32)k[10]<<16;	fallthrough;
+	case 10: c += (u32)k[9]<<8;	fallthrough;
+	case 9:  c += k[8];		fallthrough;
+	case 8:  b += (u32)k[7]<<24;	fallthrough;
+	case 7:  b += (u32)k[6]<<16;	fallthrough;
+	case 6:  b += (u32)k[5]<<8;	fallthrough;
+	case 5:  b += k[4];		fallthrough;
+	case 4:  a += (u32)k[3]<<24;	fallthrough;
+	case 3:  a += (u32)k[2]<<16;	fallthrough;
+	case 2:  a += (u32)k[1]<<8;	fallthrough;
 	case 1:  a += k[0];
 		 __jhash_final(a, b, c);
 	case 0: /* Nothing left to add */
@@ -132,8 +132,8 @@ static inline u32 jhash2(const u32 *k, u32 length, u32 initval)
 
 	/* Handle the last 3 u32's */
 	switch (length) {
-	case 3: c += k[2];	/* fall through */
-	case 2: b += k[1];	/* fall through */
+	case 3: c += k[2];	fallthrough;
+	case 2: b += k[1];	fallthrough;
 	case 1: a += k[0];
 		__jhash_final(a, b, c);
 	case 0:	/* Nothing left to add */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1983e08f5906..97c83773b6f0 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -157,11 +157,14 @@ static inline void __mm_zero_struct_page(struct page *page)
 
 	switch (sizeof(struct page)) {
 	case 80:
-		_pp[9] = 0;	/* fallthrough */
+		_pp[9] = 0;
+		fallthrough;
 	case 72:
-		_pp[8] = 0;	/* fallthrough */
+		_pp[8] = 0;
+		fallthrough;
 	case 64:
-		_pp[7] = 0;	/* fallthrough */
+		_pp[7] = 0;
+		fallthrough;
 	case 56:
 		_pp[6] = 0;
 		_pp[5] = 0;
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 6bb1a3f0258c..7bbc0e9cf084 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -137,11 +137,11 @@ static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
 		b3 = b->sig[3]; b2 = b->sig[2];				\
 		r->sig[3] = op(a3, b3);					\
 		r->sig[2] = op(a2, b2);					\
-		/* fall through */					\
+		fallthrough;						\
 	case 2:								\
 		a1 = a->sig[1]; b1 = b->sig[1];				\
 		r->sig[1] = op(a1, b1);					\
-		/* fall through */					\
+		fallthrough;						\
 	case 1:								\
 		a0 = a->sig[0]; b0 = b->sig[0];				\
 		r->sig[0] = op(a0, b0);					\
@@ -171,9 +171,9 @@ static inline void name(sigset_t *set)					\
 	switch (_NSIG_WORDS) {						\
 	case 4:	set->sig[3] = op(set->sig[3]);				\
 		set->sig[2] = op(set->sig[2]);				\
-		/* fall through */					\
+		fallthrough;						\
 	case 2:	set->sig[1] = op(set->sig[1]);				\
-		/* fall through */					\
+		fallthrough;						\
 	case 1:	set->sig[0] = op(set->sig[0]);				\
 		    break;						\
 	default:							\
@@ -194,7 +194,7 @@ static inline void sigemptyset(sigset_t *set)
 		memset(set, 0, sizeof(sigset_t));
 		break;
 	case 2: set->sig[1] = 0;
-		/* fall through */
+		fallthrough;
 	case 1:	set->sig[0] = 0;
 		break;
 	}
@@ -207,7 +207,7 @@ static inline void sigfillset(sigset_t *set)
 		memset(set, -1, sizeof(sigset_t));
 		break;
 	case 2: set->sig[1] = -1;
-		/* fall through */
+		fallthrough;
 	case 1:	set->sig[0] = -1;
 		break;
 	}
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 46881d902124..ab57cf787c1f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3745,19 +3745,19 @@ static inline bool __skb_metadata_differs(const struct sk_buff *skb_a,
 #define __it(x, op) (x -= sizeof(u##op))
 #define __it_diff(a, b, op) (*(u##op *)__it(a, op)) ^ (*(u##op *)__it(b, op))
 	case 32: diffs |= __it_diff(a, b, 64);
-		 /* fall through */
+		fallthrough;
 	case 24: diffs |= __it_diff(a, b, 64);
-		 /* fall through */
+		fallthrough;
 	case 16: diffs |= __it_diff(a, b, 64);
-		 /* fall through */
+		fallthrough;
 	case  8: diffs |= __it_diff(a, b, 64);
 		break;
 	case 28: diffs |= __it_diff(a, b, 64);
-		 /* fall through */
+		fallthrough;
 	case 20: diffs |= __it_diff(a, b, 64);
-		 /* fall through */
+		fallthrough;
 	case 12: diffs |= __it_diff(a, b, 64);
-		 /* fall through */
+		fallthrough;
 	case  4: diffs |= __it_diff(a, b, 32);
 		break;
 	}