[PATCH v2 0/5] simple sort swap function improvements

[PATCH v2 0/5] simple sort swap function improvements

[Andrey Abramov]

This is the logical continuation of the "lib/sort & lib/list_sort:
faster and smaller" series by George Spelvin (added to linux-next
recently).

Since Spectre mitigations have made indirect function calls more
expensive, and the previous patch series implements the default
simple byte copies without them, an "optimized" custom swap
function is now a waste of time as well as code.

Patches 1 to 4 replace trivial swap functions with the built-in
(which is now much faster) and are grouped by subsystem.
Being pure code deletion patches, they are sure to bring joy to
Linus's heart.

Having reviewed all call sites, only three non-trivial swap
functions remain:  arch/x86/kernel/unwind_orc.c,
kernel/jump_label.c and lib/extable.c.

Patch #5 takes the opportunity to clean up a long-standing
interface wart: the swap function's size parameter was an int,
which doesn't match the size_t element size passed to sort()
function itself.  So change it to size_t.

v1->v2: Only commit messages have changed to better explain
	the purpose of commits. (Thanks to George Spelvin and Greg KH)

Andrey Abramov (5):
  arch/arc: unwind.c: replace swap function with built-in one
  powerpc: module_[32|64].c: replace swap function with built-in one
  ocfs2: dir,refcounttree,xattr: replace swap functions with built-in
    one
  ubifs: find.c: replace swap function with built-in one
  Lib: sort.h: replace int size with size_t size in the swap function

 arch/arc/kernel/unwind.c        | 20 ++------------------
 arch/powerpc/kernel/module_32.c | 17 +----------------
 arch/powerpc/kernel/module_64.c | 17 +----------------
 arch/x86/kernel/unwind_orc.c    |  2 +-
 fs/ocfs2/dir.c                  | 13 +------------
 fs/ocfs2/refcounttree.c         | 13 +++----------
 fs/ocfs2/xattr.c                | 15 +++------------
 fs/ubifs/find.c                 |  9 +--------
 include/linux/sort.h            |  2 +-
 kernel/jump_label.c             |  2 +-
 lib/extable.c                   |  2 +-
 lib/sort.c                      |  6 +++---
 12 files changed, 19 insertions(+), 99 deletions(-)

-- 
2.21.0

[PATCH v2 0/5] simple sort swap function improvements

[Andrey Abramov]

This is the logical continuation of the "lib/sort & lib/list_sort:
faster and smaller" series by George Spelvin (added to linux-next
recently).

Since Spectre mitigations have made indirect function calls more
expensive, and the previous patch series implements the default
simple byte copies without them, an "optimized" custom swap
function is now a waste of time as well as code.

Patches 1 to 4 replace trivial swap functions with the built-in
(which is now much faster) and are grouped by subsystem.
Being pure code deletion patches, they are sure to bring joy to
Linus's heart.

Having reviewed all call sites, only three non-trivial swap
functions remain:  arch/x86/kernel/unwind_orc.c,
kernel/jump_label.c and lib/extable.c.

Patch #5 takes the opportunity to clean up a long-standing
interface wart: the swap function's size parameter was an int,
which doesn't match the size_t element size passed to sort()
function itself.  So change it to size_t.

v1->v2: Only commit messages have changed to better explain
	the purpose of commits. (Thanks to George Spelvin and Greg KH)

Andrey Abramov (5):
  arch/arc: unwind.c: replace swap function with built-in one
  powerpc: module_[32|64].c: replace swap function with built-in one
  ocfs2: dir,refcounttree,xattr: replace swap functions with built-in
    one
  ubifs: find.c: replace swap function with built-in one
  Lib: sort.h: replace int size with size_t size in the swap function

 arch/arc/kernel/unwind.c        | 20 ++------------------
 arch/powerpc/kernel/module_32.c | 17 +----------------
 arch/powerpc/kernel/module_64.c | 17 +----------------
 arch/x86/kernel/unwind_orc.c    |  2 +-
 fs/ocfs2/dir.c                  | 13 +------------
 fs/ocfs2/refcounttree.c         | 13 +++----------
 fs/ocfs2/xattr.c                | 15 +++------------
 fs/ubifs/find.c                 |  9 +--------
 include/linux/sort.h            |  2 +-
 kernel/jump_label.c             |  2 +-
 lib/extable.c                   |  2 +-
 lib/sort.c                      |  6 +++---
 12 files changed, 19 insertions(+), 99 deletions(-)

-- 
2.21.0

[PATCH v2 0/5] simple sort swap function improvements

[Andrey Abramov]

This is the logical continuation of the "lib/sort & lib/list_sort:
faster and smaller" series by George Spelvin (added to linux-next
recently).

Since Spectre mitigations have made indirect function calls more
expensive, and the previous patch series implements the default
simple byte copies without them, an "optimized" custom swap
function is now a waste of time as well as code.

Patches 1 to 4 replace trivial swap functions with the built-in
(which is now much faster) and are grouped by subsystem.
Being pure code deletion patches, they are sure to bring joy to
Linus's heart.

Having reviewed all call sites, only three non-trivial swap
functions remain:  arch/x86/kernel/unwind_orc.c,
kernel/jump_label.c and lib/extable.c.

Patch #5 takes the opportunity to clean up a long-standing
interface wart: the swap function's size parameter was an int,
which doesn't match the size_t element size passed to sort()
function itself.  So change it to size_t.

v1->v2: Only commit messages have changed to better explain
	the purpose of commits. (Thanks to George Spelvin and Greg KH)

Andrey Abramov (5):
  arch/arc: unwind.c: replace swap function with built-in one
  powerpc: module_[32|64].c: replace swap function with built-in one
  ocfs2: dir,refcounttree,xattr: replace swap functions with built-in
    one
  ubifs: find.c: replace swap function with built-in one
  Lib: sort.h: replace int size with size_t size in the swap function

 arch/arc/kernel/unwind.c        | 20 ++------------------
 arch/powerpc/kernel/module_32.c | 17 +----------------
 arch/powerpc/kernel/module_64.c | 17 +----------------
 arch/x86/kernel/unwind_orc.c    |  2 +-
 fs/ocfs2/dir.c                  | 13 +------------
 fs/ocfs2/refcounttree.c         | 13 +++----------
 fs/ocfs2/xattr.c                | 15 +++------------
 fs/ubifs/find.c                 |  9 +--------
 include/linux/sort.h            |  2 +-
 kernel/jump_label.c             |  2 +-
 lib/extable.c                   |  2 +-
 lib/sort.c                      |  6 +++---
 12 files changed, 19 insertions(+), 99 deletions(-)

-- 
2.21.0



______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v2 1/5] arch/arc: unwind.c: replace swap function with built-in one

[Andrey Abramov]

Replace swap_eh_frame_hdr_table_entries with built-in one, because
swap_eh_frame_hdr_table_entries does a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 arch/arc/kernel/unwind.c | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

diff --git a/arch/arc/kernel/unwind.c b/arch/arc/kernel/unwind.c
index 271e9fafa479..7610fe84afea 100644
--- a/arch/arc/kernel/unwind.c
+++ b/arch/arc/kernel/unwind.c
@@ -248,20 +248,6 @@ static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
 	return (e1->start > e2->start) - (e1->start < e2->start);
 }
 
-static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
-{
-	struct eh_frame_hdr_table_entry *e1 = p1;
-	struct eh_frame_hdr_table_entry *e2 = p2;
-	unsigned long v;
-
-	v = e1->start;
-	e1->start = e2->start;
-	e2->start = v;
-	v = e1->fde;
-	e1->fde = e2->fde;
-	e2->fde = v;
-}
-
 static void init_unwind_hdr(struct unwind_table *table,
 			    void *(*alloc) (unsigned long))
 {
@@ -354,10 +340,8 @@ static void init_unwind_hdr(struct unwind_table *table,
 	}
 	WARN_ON(n != header->fde_count);
 
-	sort(header->table,
-	     n,
-	     sizeof(*header->table),
-	     cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
+	sort(header->table, n,
+	     sizeof(*header->table), cmp_eh_frame_hdr_table_entries, NULL);
 
 	table->hdrsz = hdrSize;
 	smp_wmb();
-- 
2.21.0

[PATCH v2 1/5] arch/arc: unwind.c: replace swap function with built-in one

[Andrey Abramov]

Replace swap_eh_frame_hdr_table_entries with built-in one, because
swap_eh_frame_hdr_table_entries does a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub at yandex.ru>
Reviewed by: George Spelvin <lkml at sdf.org>
---
 arch/arc/kernel/unwind.c | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

diff --git a/arch/arc/kernel/unwind.c b/arch/arc/kernel/unwind.c
index 271e9fafa479..7610fe84afea 100644
--- a/arch/arc/kernel/unwind.c
+++ b/arch/arc/kernel/unwind.c
@@ -248,20 +248,6 @@ static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
 	return (e1->start > e2->start) - (e1->start < e2->start);
 }
 
-static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
-{
-	struct eh_frame_hdr_table_entry *e1 = p1;
-	struct eh_frame_hdr_table_entry *e2 = p2;
-	unsigned long v;
-
-	v = e1->start;
-	e1->start = e2->start;
-	e2->start = v;
-	v = e1->fde;
-	e1->fde = e2->fde;
-	e2->fde = v;
-}
-
 static void init_unwind_hdr(struct unwind_table *table,
 			    void *(*alloc) (unsigned long))
 {
@@ -354,10 +340,8 @@ static void init_unwind_hdr(struct unwind_table *table,
 	}
 	WARN_ON(n != header->fde_count);
 
-	sort(header->table,
-	     n,
-	     sizeof(*header->table),
-	     cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
+	sort(header->table, n,
+	     sizeof(*header->table), cmp_eh_frame_hdr_table_entries, NULL);
 
 	table->hdrsz = hdrSize;
 	smp_wmb();
-- 
2.21.0

[PATCH v2 1/5] arch/arc: unwind.c: replace swap function with built-in one

[Andrey Abramov]

Replace swap_eh_frame_hdr_table_entries with built-in one, because
swap_eh_frame_hdr_table_entries does a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 arch/arc/kernel/unwind.c | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

diff --git a/arch/arc/kernel/unwind.c b/arch/arc/kernel/unwind.c
index 271e9fafa479..7610fe84afea 100644
--- a/arch/arc/kernel/unwind.c
+++ b/arch/arc/kernel/unwind.c
@@ -248,20 +248,6 @@ static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
 	return (e1->start > e2->start) - (e1->start < e2->start);
 }
 
-static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
-{
-	struct eh_frame_hdr_table_entry *e1 = p1;
-	struct eh_frame_hdr_table_entry *e2 = p2;
-	unsigned long v;
-
-	v = e1->start;
-	e1->start = e2->start;
-	e2->start = v;
-	v = e1->fde;
-	e1->fde = e2->fde;
-	e2->fde = v;
-}
-
 static void init_unwind_hdr(struct unwind_table *table,
 			    void *(*alloc) (unsigned long))
 {
@@ -354,10 +340,8 @@ static void init_unwind_hdr(struct unwind_table *table,
 	}
 	WARN_ON(n != header->fde_count);
 
-	sort(header->table,
-	     n,
-	     sizeof(*header->table),
-	     cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
+	sort(header->table, n,
+	     sizeof(*header->table), cmp_eh_frame_hdr_table_entries, NULL);
 
 	table->hdrsz = hdrSize;
 	smp_wmb();
-- 
2.21.0



______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 1/5] arch/arc: unwind.c: replace swap function with built-in one

[Vineet Gupta]

On 3/31/19 11:31 AM, Andrey Abramov wrote:
> Replace swap_eh_frame_hdr_table_entries with built-in one, because
> swap_eh_frame_hdr_table_entries does a simple byte to byte swap.
>
> Since Spectre mitigations have made indirect function calls more
> expensive, and the default simple byte copies swap is implemented
> without them, an "optimized" custom swap function is now
> a waste of time as well as code.
>
> Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
> Reviewed by: George Spelvin <lkml@sdf.org>
>

Acked-by: Vineet Gupta <vgupta@synopsys.com>

Thx,
-Vineet

[PATCH v2 1/5] arch/arc: unwind.c: replace swap function with built-in one

[Vineet Gupta]

On 3/31/19 11:31 AM, Andrey Abramov wrote:
> Replace swap_eh_frame_hdr_table_entries with built-in one, because
> swap_eh_frame_hdr_table_entries does a simple byte to byte swap.
>
> Since Spectre mitigations have made indirect function calls more
> expensive, and the default simple byte copies swap is implemented
> without them, an "optimized" custom swap function is now
> a waste of time as well as code.
>
> Signed-off-by: Andrey Abramov <st5pub at yandex.ru>
> Reviewed by: George Spelvin <lkml at sdf.org>
>

Acked-by: Vineet Gupta <vgupta at synopsys.com>

Thx,
-Vineet

Re: [PATCH v2 1/5] arch/arc: unwind.c: replace swap function with built-in one

[Vineet Gupta]

On 3/31/19 11:31 AM, Andrey Abramov wrote:
> Replace swap_eh_frame_hdr_table_entries with built-in one, because
> swap_eh_frame_hdr_table_entries does a simple byte to byte swap.
>
> Since Spectre mitigations have made indirect function calls more
> expensive, and the default simple byte copies swap is implemented
> without them, an "optimized" custom swap function is now
> a waste of time as well as code.
>
> Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
> Reviewed by: George Spelvin <lkml@sdf.org>
>

Acked-by: Vineet Gupta <vgupta@synopsys.com>

Thx,
-Vineet

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v2 2/5] powerpc: module_[32|64].c: replace swap function with built-in one

[Andrey Abramov]

Replace relaswap with built-in one, because relaswap
does a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 arch/powerpc/kernel/module_32.c | 17 +----------------
 arch/powerpc/kernel/module_64.c | 17 +----------------
 2 files changed, 2 insertions(+), 32 deletions(-)

diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
index 88d83771f462..c311e8575d10 100644
--- a/arch/powerpc/kernel/module_32.c
+++ b/arch/powerpc/kernel/module_32.c
@@ -79,21 +79,6 @@ static int relacmp(const void *_x, const void *_y)
 		return 0;
 }
 
-static void relaswap(void *_x, void *_y, int size)
-{
-	uint32_t *x, *y, tmp;
-	int i;
-
-	y = (uint32_t *)_x;
-	x = (uint32_t *)_y;
-
-	for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
-		tmp = x[i];
-		x[i] = y[i];
-		y[i] = tmp;
-	}
-}
-
 /* Get the potential trampolines size required of the init and
    non-init sections */
 static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
@@ -130,7 +115,7 @@ static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
 			 */
 			sort((void *)hdr + sechdrs[i].sh_offset,
 			     sechdrs[i].sh_size / sizeof(Elf32_Rela),
-			     sizeof(Elf32_Rela), relacmp, relaswap);
+			     sizeof(Elf32_Rela), relacmp, NULL);
 
 			ret += count_relocs((void *)hdr
 					     + sechdrs[i].sh_offset,
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 8661eea78503..0c833d7f36f1 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -231,21 +231,6 @@ static int relacmp(const void *_x, const void *_y)
 		return 0;
 }
 
-static void relaswap(void *_x, void *_y, int size)
-{
-	uint64_t *x, *y, tmp;
-	int i;
-
-	y = (uint64_t *)_x;
-	x = (uint64_t *)_y;
-
-	for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
-		tmp = x[i];
-		x[i] = y[i];
-		y[i] = tmp;
-	}
-}
-
 /* Get size of potential trampolines required. */
 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 				    const Elf64_Shdr *sechdrs)
@@ -269,7 +254,7 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 			 */
 			sort((void *)sechdrs[i].sh_addr,
 			     sechdrs[i].sh_size / sizeof(Elf64_Rela),
-			     sizeof(Elf64_Rela), relacmp, relaswap);
+			     sizeof(Elf64_Rela), relacmp, NULL);
 
 			relocs += count_relocs((void *)sechdrs[i].sh_addr,
 					       sechdrs[i].sh_size
-- 
2.21.0

[PATCH v2 2/5] powerpc: module_[32|64].c: replace swap function with built-in one

[Andrey Abramov]

Replace relaswap with built-in one, because relaswap
does a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub at yandex.ru>
Reviewed by: George Spelvin <lkml at sdf.org>
---
 arch/powerpc/kernel/module_32.c | 17 +----------------
 arch/powerpc/kernel/module_64.c | 17 +----------------
 2 files changed, 2 insertions(+), 32 deletions(-)

diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
index 88d83771f462..c311e8575d10 100644
--- a/arch/powerpc/kernel/module_32.c
+++ b/arch/powerpc/kernel/module_32.c
@@ -79,21 +79,6 @@ static int relacmp(const void *_x, const void *_y)
 		return 0;
 }
 
-static void relaswap(void *_x, void *_y, int size)
-{
-	uint32_t *x, *y, tmp;
-	int i;
-
-	y = (uint32_t *)_x;
-	x = (uint32_t *)_y;
-
-	for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
-		tmp = x[i];
-		x[i] = y[i];
-		y[i] = tmp;
-	}
-}
-
 /* Get the potential trampolines size required of the init and
    non-init sections */
 static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
@@ -130,7 +115,7 @@ static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
 			 */
 			sort((void *)hdr + sechdrs[i].sh_offset,
 			     sechdrs[i].sh_size / sizeof(Elf32_Rela),
-			     sizeof(Elf32_Rela), relacmp, relaswap);
+			     sizeof(Elf32_Rela), relacmp, NULL);
 
 			ret += count_relocs((void *)hdr
 					     + sechdrs[i].sh_offset,
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 8661eea78503..0c833d7f36f1 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -231,21 +231,6 @@ static int relacmp(const void *_x, const void *_y)
 		return 0;
 }
 
-static void relaswap(void *_x, void *_y, int size)
-{
-	uint64_t *x, *y, tmp;
-	int i;
-
-	y = (uint64_t *)_x;
-	x = (uint64_t *)_y;
-
-	for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
-		tmp = x[i];
-		x[i] = y[i];
-		y[i] = tmp;
-	}
-}
-
 /* Get size of potential trampolines required. */
 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 				    const Elf64_Shdr *sechdrs)
@@ -269,7 +254,7 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 			 */
 			sort((void *)sechdrs[i].sh_addr,
 			     sechdrs[i].sh_size / sizeof(Elf64_Rela),
-			     sizeof(Elf64_Rela), relacmp, relaswap);
+			     sizeof(Elf64_Rela), relacmp, NULL);
 
 			relocs += count_relocs((void *)sechdrs[i].sh_addr,
 					       sechdrs[i].sh_size
-- 
2.21.0

[PATCH v2 2/5] powerpc: module_[32|64].c: replace swap function with built-in one

[Andrey Abramov]

Replace relaswap with built-in one, because relaswap
does a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 arch/powerpc/kernel/module_32.c | 17 +----------------
 arch/powerpc/kernel/module_64.c | 17 +----------------
 2 files changed, 2 insertions(+), 32 deletions(-)

diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
index 88d83771f462..c311e8575d10 100644
--- a/arch/powerpc/kernel/module_32.c
+++ b/arch/powerpc/kernel/module_32.c
@@ -79,21 +79,6 @@ static int relacmp(const void *_x, const void *_y)
 		return 0;
 }
 
-static void relaswap(void *_x, void *_y, int size)
-{
-	uint32_t *x, *y, tmp;
-	int i;
-
-	y = (uint32_t *)_x;
-	x = (uint32_t *)_y;
-
-	for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
-		tmp = x[i];
-		x[i] = y[i];
-		y[i] = tmp;
-	}
-}
-
 /* Get the potential trampolines size required of the init and
    non-init sections */
 static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
@@ -130,7 +115,7 @@ static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
 			 */
 			sort((void *)hdr + sechdrs[i].sh_offset,
 			     sechdrs[i].sh_size / sizeof(Elf32_Rela),
-			     sizeof(Elf32_Rela), relacmp, relaswap);
+			     sizeof(Elf32_Rela), relacmp, NULL);
 
 			ret += count_relocs((void *)hdr
 					     + sechdrs[i].sh_offset,
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 8661eea78503..0c833d7f36f1 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -231,21 +231,6 @@ static int relacmp(const void *_x, const void *_y)
 		return 0;
 }
 
-static void relaswap(void *_x, void *_y, int size)
-{
-	uint64_t *x, *y, tmp;
-	int i;
-
-	y = (uint64_t *)_x;
-	x = (uint64_t *)_y;
-
-	for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
-		tmp = x[i];
-		x[i] = y[i];
-		y[i] = tmp;
-	}
-}
-
 /* Get size of potential trampolines required. */
 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 				    const Elf64_Shdr *sechdrs)
@@ -269,7 +254,7 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
 			 */
 			sort((void *)sechdrs[i].sh_addr,
 			     sechdrs[i].sh_size / sizeof(Elf64_Rela),
-			     sizeof(Elf64_Rela), relacmp, relaswap);
+			     sizeof(Elf64_Rela), relacmp, NULL);
 
 			relocs += count_relocs((void *)sechdrs[i].sh_addr,
 					       sechdrs[i].sh_size
-- 
2.21.0


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 2/5] powerpc: module_[32|64].c: replace swap function with built-in one

[Michael Ellerman]

Andrey Abramov <st5pub@yandex.ru> writes:
> Replace relaswap with built-in one, because relaswap
> does a simple byte to byte swap.

I replied to v1 with an ack, which stands, this is just a clarification.

> Since Spectre mitigations have made indirect function calls more
> expensive, and the default simple byte copies swap is implemented
> without them, an "optimized" custom swap function is now
> a waste of time as well as code.

Spectre mitigations don't necessarily slow down indirect function calls
on all arches or in all configurations on all arches, so that
justification is a bit dubious.

That's not really a problem for this patch, because the existing
overhead of the function call is probably already enough to rival the
cost of the 24 byte copy.

cheers

[PATCH v2 2/5] powerpc: module_[32|64].c: replace swap function with built-in one

[Michael Ellerman]

Andrey Abramov <st5pub at yandex.ru> writes:
> Replace relaswap with built-in one, because relaswap
> does a simple byte to byte swap.

I replied to v1 with an ack, which stands, this is just a clarification.

> Since Spectre mitigations have made indirect function calls more
> expensive, and the default simple byte copies swap is implemented
> without them, an "optimized" custom swap function is now
> a waste of time as well as code.

Spectre mitigations don't necessarily slow down indirect function calls
on all arches or in all configurations on all arches, so that
justification is a bit dubious.

That's not really a problem for this patch, because the existing
overhead of the function call is probably already enough to rival the
cost of the 24 byte copy.

cheers

Re: [PATCH v2 2/5] powerpc: module_[32|64].c: replace swap function with built-in one

[Michael Ellerman]

Andrey Abramov <st5pub@yandex.ru> writes:
> Replace relaswap with built-in one, because relaswap
> does a simple byte to byte swap.

I replied to v1 with an ack, which stands, this is just a clarification.

> Since Spectre mitigations have made indirect function calls more
> expensive, and the default simple byte copies swap is implemented
> without them, an "optimized" custom swap function is now
> a waste of time as well as code.

Spectre mitigations don't necessarily slow down indirect function calls
on all arches or in all configurations on all arches, so that
justification is a bit dubious.

That's not really a problem for this patch, because the existing
overhead of the function call is probably already enough to rival the
cost of the 24 byte copy.

cheers

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 2/5] powerpc: module_[32|64].c: replace swap function with built-in one

[Michael Ellerman]

Andrey Abramov <st5pub@yandex.ru> writes:
> Replace relaswap with built-in one, because relaswap
> does a simple byte to byte swap.

I replied to v1 with an ack, which stands, this is just a clarification.

> Since Spectre mitigations have made indirect function calls more
> expensive, and the default simple byte copies swap is implemented
> without them, an "optimized" custom swap function is now
> a waste of time as well as code.

Spectre mitigations don't necessarily slow down indirect function calls
on all arches or in all configurations on all arches, so that
justification is a bit dubious.

That's not really a problem for this patch, because the existing
overhead of the function call is probably already enough to rival the
cost of the 24 byte copy.

cheers

[PATCH v2 3/5] ocfs2: dir, refcounttree, xattr: replace swap functions with built-in one

[Andrey Abramov]

Replace dx_leaf_sort_swap, swap_refcount_rec and swap_xe functions
with built-in one, because they do only a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 fs/ocfs2/dir.c          | 13 +------------
 fs/ocfs2/refcounttree.c | 13 +++----------
 fs/ocfs2/xattr.c        | 15 +++------------
 3 files changed, 7 insertions(+), 34 deletions(-)

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index c121abbdfc7d..4b86b181df0a 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -3529,16 +3529,6 @@ static int dx_leaf_sort_cmp(const void *a, const void *b)
 	return 0;
 }
 
-static void dx_leaf_sort_swap(void *a, void *b, int size)
-{
-	struct ocfs2_dx_entry *entry1 = a;
-	struct ocfs2_dx_entry *entry2 = b;
-
-	BUG_ON(size != sizeof(*entry1));
-
-	swap(*entry1, *entry2);
-}
-
 static int ocfs2_dx_leaf_same_major(struct ocfs2_dx_leaf *dx_leaf)
 {
 	struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
@@ -3799,8 +3789,7 @@ static int ocfs2_dx_dir_rebalance(struct ocfs2_super *osb, struct inode *dir,
 	 * This block is changing anyway, so we can sort it in place.
 	 */
 	sort(dx_leaf->dl_list.de_entries, num_used,
-	     sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp,
-	     dx_leaf_sort_swap);
+	     sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp, NULL);
 
 	ocfs2_journal_dirty(handle, dx_leaf_bh);
 
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 1dc9a08e8bdc..7bbc94d23a0c 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -1400,13 +1400,6 @@ static int cmp_refcount_rec_by_cpos(const void *a, const void *b)
 	return 0;
 }
 
-static void swap_refcount_rec(void *a, void *b, int size)
-{
-	struct ocfs2_refcount_rec *l = a, *r = b;
-
-	swap(*l, *r);
-}
-
 /*
  * The refcount cpos are ordered by their 64bit cpos,
  * But we will use the low 32 bit to be the e_cpos in the b-tree.
@@ -1482,7 +1475,7 @@ static int ocfs2_divide_leaf_refcount_block(struct buffer_head *ref_leaf_bh,
 	 */
 	sort(&rl->rl_recs, le16_to_cpu(rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_low_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_low_cpos, NULL);
 
 	ret = ocfs2_find_refcount_split_pos(rl, &cpos, &split_index);
 	if (ret) {
@@ -1507,11 +1500,11 @@ static int ocfs2_divide_leaf_refcount_block(struct buffer_head *ref_leaf_bh,
 
 	sort(&rl->rl_recs, le16_to_cpu(rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_cpos, NULL);
 
 	sort(&new_rl->rl_recs, le16_to_cpu(new_rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_cpos, NULL);
 
 	*split_cpos = cpos;
 	return 0;
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 3a24ce3deb01..b3e6f42baf78 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -4175,15 +4175,6 @@ static int cmp_xe(const void *a, const void *b)
 	return 0;
 }
 
-static void swap_xe(void *a, void *b, int size)
-{
-	struct ocfs2_xattr_entry *l = a, *r = b, tmp;
-
-	tmp = *l;
-	memcpy(l, r, sizeof(struct ocfs2_xattr_entry));
-	memcpy(r, &tmp, sizeof(struct ocfs2_xattr_entry));
-}
-
 /*
  * When the ocfs2_xattr_block is filled up, new bucket will be created
  * and all the xattr entries will be moved to the new bucket.
@@ -4249,7 +4240,7 @@ static void ocfs2_cp_xattr_block_to_bucket(struct inode *inode,
 	trace_ocfs2_cp_xattr_block_to_bucket_end(offset, size, off_change);
 
 	sort(target + offset, count, sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe, swap_xe);
+	     cmp_xe, NULL);
 }
 
 /*
@@ -4444,7 +4435,7 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode,
 	 */
 	sort(entries, le16_to_cpu(xh->xh_count),
 	     sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe_offset, swap_xe);
+	     cmp_xe_offset, NULL);
 
 	/* Move all name/values to the end of the bucket. */
 	xe = xh->xh_entries;
@@ -4486,7 +4477,7 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode,
 	/* sort the entries by their name_hash. */
 	sort(entries, le16_to_cpu(xh->xh_count),
 	     sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe, swap_xe);
+	     cmp_xe, NULL);
 
 	buf = bucket_buf;
 	for (i = 0; i < bucket->bu_blocks; i++, buf += blocksize)
-- 
2.21.0

[PATCH v2 3/5] ocfs2: dir, refcounttree, xattr: replace swap functions with built-in one

[Andrey Abramov]

Replace dx_leaf_sort_swap, swap_refcount_rec and swap_xe functions
with built-in one, because they do only a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub at yandex.ru>
Reviewed by: George Spelvin <lkml at sdf.org>
---
 fs/ocfs2/dir.c          | 13 +------------
 fs/ocfs2/refcounttree.c | 13 +++----------
 fs/ocfs2/xattr.c        | 15 +++------------
 3 files changed, 7 insertions(+), 34 deletions(-)

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index c121abbdfc7d..4b86b181df0a 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -3529,16 +3529,6 @@ static int dx_leaf_sort_cmp(const void *a, const void *b)
 	return 0;
 }
 
-static void dx_leaf_sort_swap(void *a, void *b, int size)
-{
-	struct ocfs2_dx_entry *entry1 = a;
-	struct ocfs2_dx_entry *entry2 = b;
-
-	BUG_ON(size != sizeof(*entry1));
-
-	swap(*entry1, *entry2);
-}
-
 static int ocfs2_dx_leaf_same_major(struct ocfs2_dx_leaf *dx_leaf)
 {
 	struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
@@ -3799,8 +3789,7 @@ static int ocfs2_dx_dir_rebalance(struct ocfs2_super *osb, struct inode *dir,
 	 * This block is changing anyway, so we can sort it in place.
 	 */
 	sort(dx_leaf->dl_list.de_entries, num_used,
-	     sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp,
-	     dx_leaf_sort_swap);
+	     sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp, NULL);
 
 	ocfs2_journal_dirty(handle, dx_leaf_bh);
 
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 1dc9a08e8bdc..7bbc94d23a0c 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -1400,13 +1400,6 @@ static int cmp_refcount_rec_by_cpos(const void *a, const void *b)
 	return 0;
 }
 
-static void swap_refcount_rec(void *a, void *b, int size)
-{
-	struct ocfs2_refcount_rec *l = a, *r = b;
-
-	swap(*l, *r);
-}
-
 /*
  * The refcount cpos are ordered by their 64bit cpos,
  * But we will use the low 32 bit to be the e_cpos in the b-tree.
@@ -1482,7 +1475,7 @@ static int ocfs2_divide_leaf_refcount_block(struct buffer_head *ref_leaf_bh,
 	 */
 	sort(&rl->rl_recs, le16_to_cpu(rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_low_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_low_cpos, NULL);
 
 	ret = ocfs2_find_refcount_split_pos(rl, &cpos, &split_index);
 	if (ret) {
@@ -1507,11 +1500,11 @@ static int ocfs2_divide_leaf_refcount_block(struct buffer_head *ref_leaf_bh,
 
 	sort(&rl->rl_recs, le16_to_cpu(rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_cpos, NULL);
 
 	sort(&new_rl->rl_recs, le16_to_cpu(new_rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_cpos, NULL);
 
 	*split_cpos = cpos;
 	return 0;
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 3a24ce3deb01..b3e6f42baf78 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -4175,15 +4175,6 @@ static int cmp_xe(const void *a, const void *b)
 	return 0;
 }
 
-static void swap_xe(void *a, void *b, int size)
-{
-	struct ocfs2_xattr_entry *l = a, *r = b, tmp;
-
-	tmp = *l;
-	memcpy(l, r, sizeof(struct ocfs2_xattr_entry));
-	memcpy(r, &tmp, sizeof(struct ocfs2_xattr_entry));
-}
-
 /*
  * When the ocfs2_xattr_block is filled up, new bucket will be created
  * and all the xattr entries will be moved to the new bucket.
@@ -4249,7 +4240,7 @@ static void ocfs2_cp_xattr_block_to_bucket(struct inode *inode,
 	trace_ocfs2_cp_xattr_block_to_bucket_end(offset, size, off_change);
 
 	sort(target + offset, count, sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe, swap_xe);
+	     cmp_xe, NULL);
 }
 
 /*
@@ -4444,7 +4435,7 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode,
 	 */
 	sort(entries, le16_to_cpu(xh->xh_count),
 	     sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe_offset, swap_xe);
+	     cmp_xe_offset, NULL);
 
 	/* Move all name/values to the end of the bucket. */
 	xe = xh->xh_entries;
@@ -4486,7 +4477,7 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode,
 	/* sort the entries by their name_hash. */
 	sort(entries, le16_to_cpu(xh->xh_count),
 	     sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe, swap_xe);
+	     cmp_xe, NULL);
 
 	buf = bucket_buf;
 	for (i = 0; i < bucket->bu_blocks; i++, buf += blocksize)
-- 
2.21.0

[PATCH v2 3/5] ocfs2: dir, refcounttree, xattr: replace swap functions with built-in one

[Andrey Abramov]

Replace dx_leaf_sort_swap, swap_refcount_rec and swap_xe functions
with built-in one, because they do only a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 fs/ocfs2/dir.c          | 13 +------------
 fs/ocfs2/refcounttree.c | 13 +++----------
 fs/ocfs2/xattr.c        | 15 +++------------
 3 files changed, 7 insertions(+), 34 deletions(-)

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index c121abbdfc7d..4b86b181df0a 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -3529,16 +3529,6 @@ static int dx_leaf_sort_cmp(const void *a, const void *b)
 	return 0;
 }
 
-static void dx_leaf_sort_swap(void *a, void *b, int size)
-{
-	struct ocfs2_dx_entry *entry1 = a;
-	struct ocfs2_dx_entry *entry2 = b;
-
-	BUG_ON(size != sizeof(*entry1));
-
-	swap(*entry1, *entry2);
-}
-
 static int ocfs2_dx_leaf_same_major(struct ocfs2_dx_leaf *dx_leaf)
 {
 	struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
@@ -3799,8 +3789,7 @@ static int ocfs2_dx_dir_rebalance(struct ocfs2_super *osb, struct inode *dir,
 	 * This block is changing anyway, so we can sort it in place.
 	 */
 	sort(dx_leaf->dl_list.de_entries, num_used,
-	     sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp,
-	     dx_leaf_sort_swap);
+	     sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp, NULL);
 
 	ocfs2_journal_dirty(handle, dx_leaf_bh);
 
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 1dc9a08e8bdc..7bbc94d23a0c 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -1400,13 +1400,6 @@ static int cmp_refcount_rec_by_cpos(const void *a, const void *b)
 	return 0;
 }
 
-static void swap_refcount_rec(void *a, void *b, int size)
-{
-	struct ocfs2_refcount_rec *l = a, *r = b;
-
-	swap(*l, *r);
-}
-
 /*
  * The refcount cpos are ordered by their 64bit cpos,
  * But we will use the low 32 bit to be the e_cpos in the b-tree.
@@ -1482,7 +1475,7 @@ static int ocfs2_divide_leaf_refcount_block(struct buffer_head *ref_leaf_bh,
 	 */
 	sort(&rl->rl_recs, le16_to_cpu(rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_low_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_low_cpos, NULL);
 
 	ret = ocfs2_find_refcount_split_pos(rl, &cpos, &split_index);
 	if (ret) {
@@ -1507,11 +1500,11 @@ static int ocfs2_divide_leaf_refcount_block(struct buffer_head *ref_leaf_bh,
 
 	sort(&rl->rl_recs, le16_to_cpu(rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_cpos, NULL);
 
 	sort(&new_rl->rl_recs, le16_to_cpu(new_rl->rl_used),
 	     sizeof(struct ocfs2_refcount_rec),
-	     cmp_refcount_rec_by_cpos, swap_refcount_rec);
+	     cmp_refcount_rec_by_cpos, NULL);
 
 	*split_cpos = cpos;
 	return 0;
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 3a24ce3deb01..b3e6f42baf78 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -4175,15 +4175,6 @@ static int cmp_xe(const void *a, const void *b)
 	return 0;
 }
 
-static void swap_xe(void *a, void *b, int size)
-{
-	struct ocfs2_xattr_entry *l = a, *r = b, tmp;
-
-	tmp = *l;
-	memcpy(l, r, sizeof(struct ocfs2_xattr_entry));
-	memcpy(r, &tmp, sizeof(struct ocfs2_xattr_entry));
-}
-
 /*
  * When the ocfs2_xattr_block is filled up, new bucket will be created
  * and all the xattr entries will be moved to the new bucket.
@@ -4249,7 +4240,7 @@ static void ocfs2_cp_xattr_block_to_bucket(struct inode *inode,
 	trace_ocfs2_cp_xattr_block_to_bucket_end(offset, size, off_change);
 
 	sort(target + offset, count, sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe, swap_xe);
+	     cmp_xe, NULL);
 }
 
 /*
@@ -4444,7 +4435,7 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode,
 	 */
 	sort(entries, le16_to_cpu(xh->xh_count),
 	     sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe_offset, swap_xe);
+	     cmp_xe_offset, NULL);
 
 	/* Move all name/values to the end of the bucket. */
 	xe = xh->xh_entries;
@@ -4486,7 +4477,7 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode,
 	/* sort the entries by their name_hash. */
 	sort(entries, le16_to_cpu(xh->xh_count),
 	     sizeof(struct ocfs2_xattr_entry),
-	     cmp_xe, swap_xe);
+	     cmp_xe, NULL);
 
 	buf = bucket_buf;
 	for (i = 0; i < bucket->bu_blocks; i++, buf += blocksize)
-- 
2.21.0


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v2 4/5] ubifs: find.c: replace swap function with built-in one

[Andrey Abramov]

Replace swap_dirty_idx function with built-in one,
because swap_dirty_idx does only a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 fs/ubifs/find.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/fs/ubifs/find.c b/fs/ubifs/find.c
index f9646835b026..5deaae7fcead 100644
--- a/fs/ubifs/find.c
+++ b/fs/ubifs/find.c
@@ -747,12 +747,6 @@ static int cmp_dirty_idx(const struct ubifs_lprops **a,
 	return lpa->dirty + lpa->free - lpb->dirty - lpb->free;
 }
 
-static void swap_dirty_idx(struct ubifs_lprops **a, struct ubifs_lprops **b,
-			   int size)
-{
-	swap(*a, *b);
-}
-
 /**
  * ubifs_save_dirty_idx_lnums - save an array of the most dirty index LEB nos.
  * @c: the UBIFS file-system description object
@@ -772,8 +766,7 @@ int ubifs_save_dirty_idx_lnums(struct ubifs_info *c)
 	       sizeof(void *) * c->dirty_idx.cnt);
 	/* Sort it so that the dirtiest is now at the end */
 	sort(c->dirty_idx.arr, c->dirty_idx.cnt, sizeof(void *),
-	     (int (*)(const void *, const void *))cmp_dirty_idx,
-	     (void (*)(void *, void *, int))swap_dirty_idx);
+	     (int (*)(const void *, const void *))cmp_dirty_idx, NULL);
 	dbg_find("found %d dirty index LEBs", c->dirty_idx.cnt);
 	if (c->dirty_idx.cnt)
 		dbg_find("dirtiest index LEB is %d with dirty %d and free %d",
-- 
2.21.0

[PATCH v2 4/5] ubifs: find.c: replace swap function with built-in one

[Andrey Abramov]

Replace swap_dirty_idx function with built-in one,
because swap_dirty_idx does only a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub at yandex.ru>
Reviewed by: George Spelvin <lkml at sdf.org>
---
 fs/ubifs/find.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/fs/ubifs/find.c b/fs/ubifs/find.c
index f9646835b026..5deaae7fcead 100644
--- a/fs/ubifs/find.c
+++ b/fs/ubifs/find.c
@@ -747,12 +747,6 @@ static int cmp_dirty_idx(const struct ubifs_lprops **a,
 	return lpa->dirty + lpa->free - lpb->dirty - lpb->free;
 }
 
-static void swap_dirty_idx(struct ubifs_lprops **a, struct ubifs_lprops **b,
-			   int size)
-{
-	swap(*a, *b);
-}
-
 /**
  * ubifs_save_dirty_idx_lnums - save an array of the most dirty index LEB nos.
  * @c: the UBIFS file-system description object
@@ -772,8 +766,7 @@ int ubifs_save_dirty_idx_lnums(struct ubifs_info *c)
 	       sizeof(void *) * c->dirty_idx.cnt);
 	/* Sort it so that the dirtiest is now at the end */
 	sort(c->dirty_idx.arr, c->dirty_idx.cnt, sizeof(void *),
-	     (int (*)(const void *, const void *))cmp_dirty_idx,
-	     (void (*)(void *, void *, int))swap_dirty_idx);
+	     (int (*)(const void *, const void *))cmp_dirty_idx, NULL);
 	dbg_find("found %d dirty index LEBs", c->dirty_idx.cnt);
 	if (c->dirty_idx.cnt)
 		dbg_find("dirtiest index LEB is %d with dirty %d and free %d",
-- 
2.21.0

[PATCH v2 4/5] ubifs: find.c: replace swap function with built-in one

[Andrey Abramov]

Replace swap_dirty_idx function with built-in one,
because swap_dirty_idx does only a simple byte to byte swap.

Since Spectre mitigations have made indirect function calls more
expensive, and the default simple byte copies swap is implemented
without them, an "optimized" custom swap function is now
a waste of time as well as code.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 fs/ubifs/find.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/fs/ubifs/find.c b/fs/ubifs/find.c
index f9646835b026..5deaae7fcead 100644
--- a/fs/ubifs/find.c
+++ b/fs/ubifs/find.c
@@ -747,12 +747,6 @@ static int cmp_dirty_idx(const struct ubifs_lprops **a,
 	return lpa->dirty + lpa->free - lpb->dirty - lpb->free;
 }
 
-static void swap_dirty_idx(struct ubifs_lprops **a, struct ubifs_lprops **b,
-			   int size)
-{
-	swap(*a, *b);
-}
-
 /**
  * ubifs_save_dirty_idx_lnums - save an array of the most dirty index LEB nos.
  * @c: the UBIFS file-system description object
@@ -772,8 +766,7 @@ int ubifs_save_dirty_idx_lnums(struct ubifs_info *c)
 	       sizeof(void *) * c->dirty_idx.cnt);
 	/* Sort it so that the dirtiest is now at the end */
 	sort(c->dirty_idx.arr, c->dirty_idx.cnt, sizeof(void *),
-	     (int (*)(const void *, const void *))cmp_dirty_idx,
-	     (void (*)(void *, void *, int))swap_dirty_idx);
+	     (int (*)(const void *, const void *))cmp_dirty_idx, NULL);
 	dbg_find("found %d dirty index LEBs", c->dirty_idx.cnt);
 	if (c->dirty_idx.cnt)
 		dbg_find("dirtiest index LEB is %d with dirty %d and free %d",
-- 
2.21.0



______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andrey Abramov]

Replace int type with size_t type of the size argument
in the swap function, also affect all its dependencies.

It's always been weird that sort() takes a size_t element size,
but passes an int size to (*swap)(). Not a bug because we don't
sort objects >2GB large, but it's ugly.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 arch/x86/kernel/unwind_orc.c | 2 +-
 include/linux/sort.h         | 2 +-
 kernel/jump_label.c          | 2 +-
 lib/extable.c                | 2 +-
 lib/sort.c                   | 6 +++---
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 89be1be1790c..1078c287198c 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -176,7 +176,7 @@ static struct orc_entry *orc_find(unsigned long ip)
 	return orc_ftrace_find(ip);
 }
 
-static void orc_sort_swap(void *_a, void *_b, int size)
+static void orc_sort_swap(void *_a, void *_b, size_t size)
 {
 	struct orc_entry *orc_a, *orc_b;
 	struct orc_entry orc_tmp;
diff --git a/include/linux/sort.h b/include/linux/sort.h
index 2b99a5dd073d..aea39d552ff7 100644
--- a/include/linux/sort.h
+++ b/include/linux/sort.h
@@ -6,6 +6,6 @@
 
 void sort(void *base, size_t num, size_t size,
 	  int (*cmp)(const void *, const void *),
-	  void (*swap)(void *, void *, int));
+	  void (*swap)(void *, void *, size_t));
 
 #endif
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index bad96b476eb6..340b788571fb 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -45,7 +45,7 @@ static int jump_label_cmp(const void *a, const void *b)
 	return 0;
 }
 
-static void jump_label_swap(void *a, void *b, int size)
+static void jump_label_swap(void *a, void *b, size_t size)
 {
 	long delta = (unsigned long)a - (unsigned long)b;
 	struct jump_entry *jea = a;
diff --git a/lib/extable.c b/lib/extable.c
index f54996fdd0b8..db2888342cd7 100644
--- a/lib/extable.c
+++ b/lib/extable.c
@@ -28,7 +28,7 @@ static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
 #ifndef ARCH_HAS_RELATIVE_EXTABLE
 #define swap_ex		NULL
 #else
-static void swap_ex(void *a, void *b, int size)
+static void swap_ex(void *a, void *b, size_t size)
 {
 	struct exception_table_entry *x = a, *y = b, tmp;
 	int delta = b - a;
diff --git a/lib/sort.c b/lib/sort.c
index 50855ea8c262..60fbbc29104a 100644
--- a/lib/sort.c
+++ b/lib/sort.c
@@ -114,7 +114,7 @@ static void swap_bytes(void *a, void *b, size_t n)
 	} while (n);
 }
 
-typedef void (*swap_func_t)(void *a, void *b, int size);
+typedef void (*swap_func_t)(void *a, void *b, size_t size);
 
 /*
  * The values are arbitrary as long as they can't be confused with
@@ -138,7 +138,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
 	else if (swap_func == SWAP_BYTES)
 		swap_bytes(a, b, size);
 	else
-		swap_func(a, b, (int)size);
+		swap_func(a, b, size);
 }
 
 /**
@@ -187,7 +187,7 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
  */
 void sort(void *base, size_t num, size_t size,
 	  int (*cmp_func)(const void *, const void *),
-	  void (*swap_func)(void *, void *, int size))
+	  void (*swap_func)(void *, void *, size_t size))
 {
 	/* pre-scale counters for performance */
 	size_t n = num * size, a = (num/2) * size;
-- 
2.21.0

[PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andrey Abramov]

Replace int type with size_t type of the size argument
in the swap function, also affect all its dependencies.

It's always been weird that sort() takes a size_t element size,
but passes an int size to (*swap)(). Not a bug because we don't
sort objects >2GB large, but it's ugly.

Signed-off-by: Andrey Abramov <st5pub at yandex.ru>
Reviewed by: George Spelvin <lkml at sdf.org>
---
 arch/x86/kernel/unwind_orc.c | 2 +-
 include/linux/sort.h         | 2 +-
 kernel/jump_label.c          | 2 +-
 lib/extable.c                | 2 +-
 lib/sort.c                   | 6 +++---
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 89be1be1790c..1078c287198c 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -176,7 +176,7 @@ static struct orc_entry *orc_find(unsigned long ip)
 	return orc_ftrace_find(ip);
 }
 
-static void orc_sort_swap(void *_a, void *_b, int size)
+static void orc_sort_swap(void *_a, void *_b, size_t size)
 {
 	struct orc_entry *orc_a, *orc_b;
 	struct orc_entry orc_tmp;
diff --git a/include/linux/sort.h b/include/linux/sort.h
index 2b99a5dd073d..aea39d552ff7 100644
--- a/include/linux/sort.h
+++ b/include/linux/sort.h
@@ -6,6 +6,6 @@
 
 void sort(void *base, size_t num, size_t size,
 	  int (*cmp)(const void *, const void *),
-	  void (*swap)(void *, void *, int));
+	  void (*swap)(void *, void *, size_t));
 
 #endif
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index bad96b476eb6..340b788571fb 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -45,7 +45,7 @@ static int jump_label_cmp(const void *a, const void *b)
 	return 0;
 }
 
-static void jump_label_swap(void *a, void *b, int size)
+static void jump_label_swap(void *a, void *b, size_t size)
 {
 	long delta = (unsigned long)a - (unsigned long)b;
 	struct jump_entry *jea = a;
diff --git a/lib/extable.c b/lib/extable.c
index f54996fdd0b8..db2888342cd7 100644
--- a/lib/extable.c
+++ b/lib/extable.c
@@ -28,7 +28,7 @@ static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
 #ifndef ARCH_HAS_RELATIVE_EXTABLE
 #define swap_ex		NULL
 #else
-static void swap_ex(void *a, void *b, int size)
+static void swap_ex(void *a, void *b, size_t size)
 {
 	struct exception_table_entry *x = a, *y = b, tmp;
 	int delta = b - a;
diff --git a/lib/sort.c b/lib/sort.c
index 50855ea8c262..60fbbc29104a 100644
--- a/lib/sort.c
+++ b/lib/sort.c
@@ -114,7 +114,7 @@ static void swap_bytes(void *a, void *b, size_t n)
 	} while (n);
 }
 
-typedef void (*swap_func_t)(void *a, void *b, int size);
+typedef void (*swap_func_t)(void *a, void *b, size_t size);
 
 /*
  * The values are arbitrary as long as they can't be confused with
@@ -138,7 +138,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
 	else if (swap_func == SWAP_BYTES)
 		swap_bytes(a, b, size);
 	else
-		swap_func(a, b, (int)size);
+		swap_func(a, b, size);
 }
 
 /**
@@ -187,7 +187,7 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
  */
 void sort(void *base, size_t num, size_t size,
 	  int (*cmp_func)(const void *, const void *),
-	  void (*swap_func)(void *, void *, int size))
+	  void (*swap_func)(void *, void *, size_t size))
 {
 	/* pre-scale counters for performance */
 	size_t n = num * size, a = (num/2) * size;
-- 
2.21.0

[PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andrey Abramov]

Replace int type with size_t type of the size argument
in the swap function, also affect all its dependencies.

It's always been weird that sort() takes a size_t element size,
but passes an int size to (*swap)(). Not a bug because we don't
sort objects >2GB large, but it's ugly.

Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
Reviewed by: George Spelvin <lkml@sdf.org>
---
 arch/x86/kernel/unwind_orc.c | 2 +-
 include/linux/sort.h         | 2 +-
 kernel/jump_label.c          | 2 +-
 lib/extable.c                | 2 +-
 lib/sort.c                   | 6 +++---
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 89be1be1790c..1078c287198c 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -176,7 +176,7 @@ static struct orc_entry *orc_find(unsigned long ip)
 	return orc_ftrace_find(ip);
 }
 
-static void orc_sort_swap(void *_a, void *_b, int size)
+static void orc_sort_swap(void *_a, void *_b, size_t size)
 {
 	struct orc_entry *orc_a, *orc_b;
 	struct orc_entry orc_tmp;
diff --git a/include/linux/sort.h b/include/linux/sort.h
index 2b99a5dd073d..aea39d552ff7 100644
--- a/include/linux/sort.h
+++ b/include/linux/sort.h
@@ -6,6 +6,6 @@
 
 void sort(void *base, size_t num, size_t size,
 	  int (*cmp)(const void *, const void *),
-	  void (*swap)(void *, void *, int));
+	  void (*swap)(void *, void *, size_t));
 
 #endif
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index bad96b476eb6..340b788571fb 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -45,7 +45,7 @@ static int jump_label_cmp(const void *a, const void *b)
 	return 0;
 }
 
-static void jump_label_swap(void *a, void *b, int size)
+static void jump_label_swap(void *a, void *b, size_t size)
 {
 	long delta = (unsigned long)a - (unsigned long)b;
 	struct jump_entry *jea = a;
diff --git a/lib/extable.c b/lib/extable.c
index f54996fdd0b8..db2888342cd7 100644
--- a/lib/extable.c
+++ b/lib/extable.c
@@ -28,7 +28,7 @@ static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
 #ifndef ARCH_HAS_RELATIVE_EXTABLE
 #define swap_ex		NULL
 #else
-static void swap_ex(void *a, void *b, int size)
+static void swap_ex(void *a, void *b, size_t size)
 {
 	struct exception_table_entry *x = a, *y = b, tmp;
 	int delta = b - a;
diff --git a/lib/sort.c b/lib/sort.c
index 50855ea8c262..60fbbc29104a 100644
--- a/lib/sort.c
+++ b/lib/sort.c
@@ -114,7 +114,7 @@ static void swap_bytes(void *a, void *b, size_t n)
 	} while (n);
 }
 
-typedef void (*swap_func_t)(void *a, void *b, int size);
+typedef void (*swap_func_t)(void *a, void *b, size_t size);
 
 /*
  * The values are arbitrary as long as they can't be confused with
@@ -138,7 +138,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
 	else if (swap_func == SWAP_BYTES)
 		swap_bytes(a, b, size);
 	else
-		swap_func(a, b, (int)size);
+		swap_func(a, b, size);
 }
 
 /**
@@ -187,7 +187,7 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
  */
 void sort(void *base, size_t num, size_t size,
 	  int (*cmp_func)(const void *, const void *),
-	  void (*swap_func)(void *, void *, int size))
+	  void (*swap_func)(void *, void *, size_t size))
 {
 	/* pre-scale counters for performance */
 	size_t n = num * size, a = (num/2) * size;
-- 
2.21.0



______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andy Shevchenko]

On Sun, Mar 31, 2019 at 09:52:50PM +0300, Andrey Abramov wrote:
> Replace int type with size_t type of the size argument
> in the swap function, also affect all its dependencies.
> 
> It's always been weird that sort() takes a size_t element size,
> but passes an int size to (*swap)(). Not a bug because we don't
> sort objects >2GB large, but it's ugly.

Hmm... If (*swap)() is called recursively it means the change might increase
stack usage on 64-bit platforms.

Am I missing something?

> 
> Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
> Reviewed by: George Spelvin <lkml@sdf.org>
> ---
>  arch/x86/kernel/unwind_orc.c | 2 +-
>  include/linux/sort.h         | 2 +-
>  kernel/jump_label.c          | 2 +-
>  lib/extable.c                | 2 +-
>  lib/sort.c                   | 6 +++---
>  5 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
> index 89be1be1790c..1078c287198c 100644
> --- a/arch/x86/kernel/unwind_orc.c
> +++ b/arch/x86/kernel/unwind_orc.c
> @@ -176,7 +176,7 @@ static struct orc_entry *orc_find(unsigned long ip)
>  	return orc_ftrace_find(ip);
>  }
>  
> -static void orc_sort_swap(void *_a, void *_b, int size)
> +static void orc_sort_swap(void *_a, void *_b, size_t size)
>  {
>  	struct orc_entry *orc_a, *orc_b;
>  	struct orc_entry orc_tmp;
> diff --git a/include/linux/sort.h b/include/linux/sort.h
> index 2b99a5dd073d..aea39d552ff7 100644
> --- a/include/linux/sort.h
> +++ b/include/linux/sort.h
> @@ -6,6 +6,6 @@
>  
>  void sort(void *base, size_t num, size_t size,
>  	  int (*cmp)(const void *, const void *),
> -	  void (*swap)(void *, void *, int));
> +	  void (*swap)(void *, void *, size_t));
>  
>  #endif
> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
> index bad96b476eb6..340b788571fb 100644
> --- a/kernel/jump_label.c
> +++ b/kernel/jump_label.c
> @@ -45,7 +45,7 @@ static int jump_label_cmp(const void *a, const void *b)
>  	return 0;
>  }
>  
> -static void jump_label_swap(void *a, void *b, int size)
> +static void jump_label_swap(void *a, void *b, size_t size)
>  {
>  	long delta = (unsigned long)a - (unsigned long)b;
>  	struct jump_entry *jea = a;
> diff --git a/lib/extable.c b/lib/extable.c
> index f54996fdd0b8..db2888342cd7 100644
> --- a/lib/extable.c
> +++ b/lib/extable.c
> @@ -28,7 +28,7 @@ static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
>  #ifndef ARCH_HAS_RELATIVE_EXTABLE
>  #define swap_ex		NULL
>  #else
> -static void swap_ex(void *a, void *b, int size)
> +static void swap_ex(void *a, void *b, size_t size)
>  {
>  	struct exception_table_entry *x = a, *y = b, tmp;
>  	int delta = b - a;
> diff --git a/lib/sort.c b/lib/sort.c
> index 50855ea8c262..60fbbc29104a 100644
> --- a/lib/sort.c
> +++ b/lib/sort.c
> @@ -114,7 +114,7 @@ static void swap_bytes(void *a, void *b, size_t n)
>  	} while (n);
>  }
>  
> -typedef void (*swap_func_t)(void *a, void *b, int size);
> +typedef void (*swap_func_t)(void *a, void *b, size_t size);
>  
>  /*
>   * The values are arbitrary as long as they can't be confused with
> @@ -138,7 +138,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
>  	else if (swap_func == SWAP_BYTES)
>  		swap_bytes(a, b, size);
>  	else
> -		swap_func(a, b, (int)size);
> +		swap_func(a, b, size);
>  }
>  
>  /**
> @@ -187,7 +187,7 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
>   */
>  void sort(void *base, size_t num, size_t size,
>  	  int (*cmp_func)(const void *, const void *),
> -	  void (*swap_func)(void *, void *, int size))
> +	  void (*swap_func)(void *, void *, size_t size))
>  {
>  	/* pre-scale counters for performance */
>  	size_t n = num * size, a = (num/2) * size;
> -- 
> 2.21.0
> 
> 

-- 
With Best Regards,
Andy Shevchenko

[PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andy Shevchenko]

On Sun, Mar 31, 2019@09:52:50PM +0300, Andrey Abramov wrote:
> Replace int type with size_t type of the size argument
> in the swap function, also affect all its dependencies.
> 
> It's always been weird that sort() takes a size_t element size,
> but passes an int size to (*swap)(). Not a bug because we don't
> sort objects >2GB large, but it's ugly.

Hmm... If (*swap)() is called recursively it means the change might increase
stack usage on 64-bit platforms.

Am I missing something?

> 
> Signed-off-by: Andrey Abramov <st5pub at yandex.ru>
> Reviewed by: George Spelvin <lkml at sdf.org>
> ---
>  arch/x86/kernel/unwind_orc.c | 2 +-
>  include/linux/sort.h         | 2 +-
>  kernel/jump_label.c          | 2 +-
>  lib/extable.c                | 2 +-
>  lib/sort.c                   | 6 +++---
>  5 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
> index 89be1be1790c..1078c287198c 100644
> --- a/arch/x86/kernel/unwind_orc.c
> +++ b/arch/x86/kernel/unwind_orc.c
> @@ -176,7 +176,7 @@ static struct orc_entry *orc_find(unsigned long ip)
>  	return orc_ftrace_find(ip);
>  }
>  
> -static void orc_sort_swap(void *_a, void *_b, int size)
> +static void orc_sort_swap(void *_a, void *_b, size_t size)
>  {
>  	struct orc_entry *orc_a, *orc_b;
>  	struct orc_entry orc_tmp;
> diff --git a/include/linux/sort.h b/include/linux/sort.h
> index 2b99a5dd073d..aea39d552ff7 100644
> --- a/include/linux/sort.h
> +++ b/include/linux/sort.h
> @@ -6,6 +6,6 @@
>  
>  void sort(void *base, size_t num, size_t size,
>  	  int (*cmp)(const void *, const void *),
> -	  void (*swap)(void *, void *, int));
> +	  void (*swap)(void *, void *, size_t));
>  
>  #endif
> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
> index bad96b476eb6..340b788571fb 100644
> --- a/kernel/jump_label.c
> +++ b/kernel/jump_label.c
> @@ -45,7 +45,7 @@ static int jump_label_cmp(const void *a, const void *b)
>  	return 0;
>  }
>  
> -static void jump_label_swap(void *a, void *b, int size)
> +static void jump_label_swap(void *a, void *b, size_t size)
>  {
>  	long delta = (unsigned long)a - (unsigned long)b;
>  	struct jump_entry *jea = a;
> diff --git a/lib/extable.c b/lib/extable.c
> index f54996fdd0b8..db2888342cd7 100644
> --- a/lib/extable.c
> +++ b/lib/extable.c
> @@ -28,7 +28,7 @@ static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
>  #ifndef ARCH_HAS_RELATIVE_EXTABLE
>  #define swap_ex		NULL
>  #else
> -static void swap_ex(void *a, void *b, int size)
> +static void swap_ex(void *a, void *b, size_t size)
>  {
>  	struct exception_table_entry *x = a, *y = b, tmp;
>  	int delta = b - a;
> diff --git a/lib/sort.c b/lib/sort.c
> index 50855ea8c262..60fbbc29104a 100644
> --- a/lib/sort.c
> +++ b/lib/sort.c
> @@ -114,7 +114,7 @@ static void swap_bytes(void *a, void *b, size_t n)
>  	} while (n);
>  }
>  
> -typedef void (*swap_func_t)(void *a, void *b, int size);
> +typedef void (*swap_func_t)(void *a, void *b, size_t size);
>  
>  /*
>   * The values are arbitrary as long as they can't be confused with
> @@ -138,7 +138,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
>  	else if (swap_func == SWAP_BYTES)
>  		swap_bytes(a, b, size);
>  	else
> -		swap_func(a, b, (int)size);
> +		swap_func(a, b, size);
>  }
>  
>  /**
> @@ -187,7 +187,7 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
>   */
>  void sort(void *base, size_t num, size_t size,
>  	  int (*cmp_func)(const void *, const void *),
> -	  void (*swap_func)(void *, void *, int size))
> +	  void (*swap_func)(void *, void *, size_t size))
>  {
>  	/* pre-scale counters for performance */
>  	size_t n = num * size, a = (num/2) * size;
> -- 
> 2.21.0
> 
> 

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andy Shevchenko]

On Sun, Mar 31, 2019 at 09:52:50PM +0300, Andrey Abramov wrote:
> Replace int type with size_t type of the size argument
> in the swap function, also affect all its dependencies.
> 
> It's always been weird that sort() takes a size_t element size,
> but passes an int size to (*swap)(). Not a bug because we don't
> sort objects >2GB large, but it's ugly.

Hmm... If (*swap)() is called recursively it means the change might increase
stack usage on 64-bit platforms.

Am I missing something?

> 
> Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
> Reviewed by: George Spelvin <lkml@sdf.org>
> ---
>  arch/x86/kernel/unwind_orc.c | 2 +-
>  include/linux/sort.h         | 2 +-
>  kernel/jump_label.c          | 2 +-
>  lib/extable.c                | 2 +-
>  lib/sort.c                   | 6 +++---
>  5 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
> index 89be1be1790c..1078c287198c 100644
> --- a/arch/x86/kernel/unwind_orc.c
> +++ b/arch/x86/kernel/unwind_orc.c
> @@ -176,7 +176,7 @@ static struct orc_entry *orc_find(unsigned long ip)
>  	return orc_ftrace_find(ip);
>  }
>  
> -static void orc_sort_swap(void *_a, void *_b, int size)
> +static void orc_sort_swap(void *_a, void *_b, size_t size)
>  {
>  	struct orc_entry *orc_a, *orc_b;
>  	struct orc_entry orc_tmp;
> diff --git a/include/linux/sort.h b/include/linux/sort.h
> index 2b99a5dd073d..aea39d552ff7 100644
> --- a/include/linux/sort.h
> +++ b/include/linux/sort.h
> @@ -6,6 +6,6 @@
>  
>  void sort(void *base, size_t num, size_t size,
>  	  int (*cmp)(const void *, const void *),
> -	  void (*swap)(void *, void *, int));
> +	  void (*swap)(void *, void *, size_t));
>  
>  #endif
> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
> index bad96b476eb6..340b788571fb 100644
> --- a/kernel/jump_label.c
> +++ b/kernel/jump_label.c
> @@ -45,7 +45,7 @@ static int jump_label_cmp(const void *a, const void *b)
>  	return 0;
>  }
>  
> -static void jump_label_swap(void *a, void *b, int size)
> +static void jump_label_swap(void *a, void *b, size_t size)
>  {
>  	long delta = (unsigned long)a - (unsigned long)b;
>  	struct jump_entry *jea = a;
> diff --git a/lib/extable.c b/lib/extable.c
> index f54996fdd0b8..db2888342cd7 100644
> --- a/lib/extable.c
> +++ b/lib/extable.c
> @@ -28,7 +28,7 @@ static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
>  #ifndef ARCH_HAS_RELATIVE_EXTABLE
>  #define swap_ex		NULL
>  #else
> -static void swap_ex(void *a, void *b, int size)
> +static void swap_ex(void *a, void *b, size_t size)
>  {
>  	struct exception_table_entry *x = a, *y = b, tmp;
>  	int delta = b - a;
> diff --git a/lib/sort.c b/lib/sort.c
> index 50855ea8c262..60fbbc29104a 100644
> --- a/lib/sort.c
> +++ b/lib/sort.c
> @@ -114,7 +114,7 @@ static void swap_bytes(void *a, void *b, size_t n)
>  	} while (n);
>  }
>  
> -typedef void (*swap_func_t)(void *a, void *b, int size);
> +typedef void (*swap_func_t)(void *a, void *b, size_t size);
>  
>  /*
>   * The values are arbitrary as long as they can't be confused with
> @@ -138,7 +138,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
>  	else if (swap_func == SWAP_BYTES)
>  		swap_bytes(a, b, size);
>  	else
> -		swap_func(a, b, (int)size);
> +		swap_func(a, b, size);
>  }
>  
>  /**
> @@ -187,7 +187,7 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
>   */
>  void sort(void *base, size_t num, size_t size,
>  	  int (*cmp_func)(const void *, const void *),
> -	  void (*swap_func)(void *, void *, int size))
> +	  void (*swap_func)(void *, void *, size_t size))
>  {
>  	/* pre-scale counters for performance */
>  	size_t n = num * size, a = (num/2) * size;
> -- 
> 2.21.0
> 
> 

-- 
With Best Regards,
Andy Shevchenko



______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andy Shevchenko]

On Sun, Mar 31, 2019 at 09:52:50PM +0300, Andrey Abramov wrote:
> Replace int type with size_t type of the size argument
> in the swap function, also affect all its dependencies.
> 
> It's always been weird that sort() takes a size_t element size,
> but passes an int size to (*swap)(). Not a bug because we don't
> sort objects >2GB large, but it's ugly.

Hmm... If (*swap)() is called recursively it means the change might increase
stack usage on 64-bit platforms.

Am I missing something?

> 
> Signed-off-by: Andrey Abramov <st5pub@yandex.ru>
> Reviewed by: George Spelvin <lkml@sdf.org>
> ---
>  arch/x86/kernel/unwind_orc.c | 2 +-
>  include/linux/sort.h         | 2 +-
>  kernel/jump_label.c          | 2 +-
>  lib/extable.c                | 2 +-
>  lib/sort.c                   | 6 +++---
>  5 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
> index 89be1be1790c..1078c287198c 100644
> --- a/arch/x86/kernel/unwind_orc.c
> +++ b/arch/x86/kernel/unwind_orc.c
> @@ -176,7 +176,7 @@ static struct orc_entry *orc_find(unsigned long ip)
>  	return orc_ftrace_find(ip);
>  }
>  
> -static void orc_sort_swap(void *_a, void *_b, int size)
> +static void orc_sort_swap(void *_a, void *_b, size_t size)
>  {
>  	struct orc_entry *orc_a, *orc_b;
>  	struct orc_entry orc_tmp;
> diff --git a/include/linux/sort.h b/include/linux/sort.h
> index 2b99a5dd073d..aea39d552ff7 100644
> --- a/include/linux/sort.h
> +++ b/include/linux/sort.h
> @@ -6,6 +6,6 @@
>  
>  void sort(void *base, size_t num, size_t size,
>  	  int (*cmp)(const void *, const void *),
> -	  void (*swap)(void *, void *, int));
> +	  void (*swap)(void *, void *, size_t));
>  
>  #endif
> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
> index bad96b476eb6..340b788571fb 100644
> --- a/kernel/jump_label.c
> +++ b/kernel/jump_label.c
> @@ -45,7 +45,7 @@ static int jump_label_cmp(const void *a, const void *b)
>  	return 0;
>  }
>  
> -static void jump_label_swap(void *a, void *b, int size)
> +static void jump_label_swap(void *a, void *b, size_t size)
>  {
>  	long delta = (unsigned long)a - (unsigned long)b;
>  	struct jump_entry *jea = a;
> diff --git a/lib/extable.c b/lib/extable.c
> index f54996fdd0b8..db2888342cd7 100644
> --- a/lib/extable.c
> +++ b/lib/extable.c
> @@ -28,7 +28,7 @@ static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
>  #ifndef ARCH_HAS_RELATIVE_EXTABLE
>  #define swap_ex		NULL
>  #else
> -static void swap_ex(void *a, void *b, int size)
> +static void swap_ex(void *a, void *b, size_t size)
>  {
>  	struct exception_table_entry *x = a, *y = b, tmp;
>  	int delta = b - a;
> diff --git a/lib/sort.c b/lib/sort.c
> index 50855ea8c262..60fbbc29104a 100644
> --- a/lib/sort.c
> +++ b/lib/sort.c
> @@ -114,7 +114,7 @@ static void swap_bytes(void *a, void *b, size_t n)
>  	} while (n);
>  }
>  
> -typedef void (*swap_func_t)(void *a, void *b, int size);
> +typedef void (*swap_func_t)(void *a, void *b, size_t size);
>  
>  /*
>   * The values are arbitrary as long as they can't be confused with
> @@ -138,7 +138,7 @@ static void do_swap(void *a, void *b, size_t size, swap_func_t swap_func)
>  	else if (swap_func == SWAP_BYTES)
>  		swap_bytes(a, b, size);
>  	else
> -		swap_func(a, b, (int)size);
> +		swap_func(a, b, size);
>  }
>  
>  /**
> @@ -187,7 +187,7 @@ static size_t parent(size_t i, unsigned int lsbit, size_t size)
>   */
>  void sort(void *base, size_t num, size_t size,
>  	  int (*cmp_func)(const void *, const void *),
> -	  void (*swap_func)(void *, void *, int size))
> +	  void (*swap_func)(void *, void *, size_t size))
>  {
>  	/* pre-scale counters for performance */
>  	size_t n = num * size, a = (num/2) * size;
> -- 
> 2.21.0
> 
> 

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[George Spelvin]

On Mon, 1 Apr 2019 at 12:35:55 +0300, Andy Shevchenko wrote:
> Hmm... If (*swap)() is called recursively it means the change might increase
> stack usage on 64-bit platforms.
> 
> Am I missing something?

Under what conceivable circumstance would someone write a recursive
(*swap)() function?

You're technically right, but the precondition is more fantastical
than "if the U.K.'s parliament get their shit together before the
12th", so I have a hard time worrying about it.

But you did make me think of something: the whole reason swap()
takes a size argument is for the benefit of the (no longer existing)
generic swap functions.  All of the custom swap functions ignore
it.

So how about *deleting* the parameter instead?  That simplifies
everything.

[PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[George Spelvin]

On Mon, 1 Apr 2019@12:35:55 +0300, Andy Shevchenko wrote:
> Hmm... If (*swap)() is called recursively it means the change might increase
> stack usage on 64-bit platforms.
> 
> Am I missing something?

Under what conceivable circumstance would someone write a recursive
(*swap)() function?

You're technically right, but the precondition is more fantastical
than "if the U.K.'s parliament get their shit together before the
12th", so I have a hard time worrying about it.

But you did make me think of something: the whole reason swap()
takes a size argument is for the benefit of the (no longer existing)
generic swap functions.  All of the custom swap functions ignore
it.

So how about *deleting* the parameter instead?  That simplifies
everything.

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[George Spelvin]

On Mon, 1 Apr 2019 at 12:35:55 +0300, Andy Shevchenko wrote:
> Hmm... If (*swap)() is called recursively it means the change might increase
> stack usage on 64-bit platforms.
> 
> Am I missing something?

Under what conceivable circumstance would someone write a recursive
(*swap)() function?

You're technically right, but the precondition is more fantastical
than "if the U.K.'s parliament get their shit together before the
12th", so I have a hard time worrying about it.

But you did make me think of something: the whole reason swap()
takes a size argument is for the benefit of the (no longer existing)
generic swap functions.  All of the custom swap functions ignore
it.

So how about *deleting* the parameter instead?  That simplifies
everything.

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[George Spelvin]

On Mon, 1 Apr 2019 at 12:35:55 +0300, Andy Shevchenko wrote:
> Hmm... If (*swap)() is called recursively it means the change might increase
> stack usage on 64-bit platforms.
> 
> Am I missing something?

Under what conceivable circumstance would someone write a recursive
(*swap)() function?

You're technically right, but the precondition is more fantastical
than "if the U.K.'s parliament get their shit together before the
12th", so I have a hard time worrying about it.

But you did make me think of something: the whole reason swap()
takes a size argument is for the benefit of the (no longer existing)
generic swap functions.  All of the custom swap functions ignore
it.

So how about *deleting* the parameter instead?  That simplifies
everything.

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andy Shevchenko]

On Mon, Apr 01, 2019 at 09:56:07AM +0000, George Spelvin wrote:
> On Mon, 1 Apr 2019 at 12:35:55 +0300, Andy Shevchenko wrote:
> > Hmm... If (*swap)() is called recursively it means the change might increase
> > stack usage on 64-bit platforms.
> > 
> > Am I missing something?
> 
> Under what conceivable circumstance would someone write a recursive
> (*swap)() function?
> 
> You're technically right, but the precondition is more fantastical
> than "if the U.K.'s parliament get their shit together before the
> 12th", so I have a hard time worrying about it.
> 
> But you did make me think of something: the whole reason swap()
> takes a size argument is for the benefit of the (no longer existing)
> generic swap functions.  All of the custom swap functions ignore
> it.
> 
> So how about *deleting* the parameter instead?  That simplifies
> everything.

I like this idea!

-- 
With Best Regards,
Andy Shevchenko

[PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andy Shevchenko]

On Mon, Apr 01, 2019@09:56:07AM +0000, George Spelvin wrote:
> On Mon, 1 Apr 2019@12:35:55 +0300, Andy Shevchenko wrote:
> > Hmm... If (*swap)() is called recursively it means the change might increase
> > stack usage on 64-bit platforms.
> > 
> > Am I missing something?
> 
> Under what conceivable circumstance would someone write a recursive
> (*swap)() function?
> 
> You're technically right, but the precondition is more fantastical
> than "if the U.K.'s parliament get their shit together before the
> 12th", so I have a hard time worrying about it.
> 
> But you did make me think of something: the whole reason swap()
> takes a size argument is for the benefit of the (no longer existing)
> generic swap functions.  All of the custom swap functions ignore
> it.
> 
> So how about *deleting* the parameter instead?  That simplifies
> everything.

I like this idea!

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andy Shevchenko]

On Mon, Apr 01, 2019 at 09:56:07AM +0000, George Spelvin wrote:
> On Mon, 1 Apr 2019 at 12:35:55 +0300, Andy Shevchenko wrote:
> > Hmm... If (*swap)() is called recursively it means the change might increase
> > stack usage on 64-bit platforms.
> > 
> > Am I missing something?
> 
> Under what conceivable circumstance would someone write a recursive
> (*swap)() function?
> 
> You're technically right, but the precondition is more fantastical
> than "if the U.K.'s parliament get their shit together before the
> 12th", so I have a hard time worrying about it.
> 
> But you did make me think of something: the whole reason swap()
> takes a size argument is for the benefit of the (no longer existing)
> generic swap functions.  All of the custom swap functions ignore
> it.
> 
> So how about *deleting* the parameter instead?  That simplifies
> everything.

I like this idea!

-- 
With Best Regards,
Andy Shevchenko



______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 5/5] Lib: sort.h: replace int size with size_t size in the swap function

[Andy Shevchenko]

On Mon, Apr 01, 2019 at 09:56:07AM +0000, George Spelvin wrote:
> On Mon, 1 Apr 2019 at 12:35:55 +0300, Andy Shevchenko wrote:
> > Hmm... If (*swap)() is called recursively it means the change might increase
> > stack usage on 64-bit platforms.
> > 
> > Am I missing something?
> 
> Under what conceivable circumstance would someone write a recursive
> (*swap)() function?
> 
> You're technically right, but the precondition is more fantastical
> than "if the U.K.'s parliament get their shit together before the
> 12th", so I have a hard time worrying about it.
> 
> But you did make me think of something: the whole reason swap()
> takes a size argument is for the benefit of the (no longer existing)
> generic swap functions.  All of the custom swap functions ignore
> it.
> 
> So how about *deleting* the parameter instead?  That simplifies
> everything.

I like this idea!

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 0/5] simple sort swap function improvements

[Andy Shevchenko]

On Sun, Mar 31, 2019 at 09:28:03PM +0300, Andrey Abramov wrote:
> This is the logical continuation of the "lib/sort & lib/list_sort:
> faster and smaller" series by George Spelvin (added to linux-next
> recently).
> 
> Since Spectre mitigations have made indirect function calls more
> expensive, and the previous patch series implements the default
> simple byte copies without them, an "optimized" custom swap
> function is now a waste of time as well as code.
> 
> Patches 1 to 4 replace trivial swap functions with the built-in
> (which is now much faster) and are grouped by subsystem.
> Being pure code deletion patches, they are sure to bring joy to
> Linus's heart.
> 
> Having reviewed all call sites, only three non-trivial swap
> functions remain:  arch/x86/kernel/unwind_orc.c,
> kernel/jump_label.c and lib/extable.c.
> 
> Patch #5 takes the opportunity to clean up a long-standing
> interface wart: the swap function's size parameter was an int,
> which doesn't match the size_t element size passed to sort()
> function itself.  So change it to size_t.
> 
> v1->v2: Only commit messages have changed to better explain
> 	the purpose of commits. (Thanks to George Spelvin and Greg KH)


Thanks for an update.

Hint:
scripts/get_maintainer.pl --git --git-min-percent=67 ...

(Note 67% magic value)

> 
> Andrey Abramov (5):
>   arch/arc: unwind.c: replace swap function with built-in one
>   powerpc: module_[32|64].c: replace swap function with built-in one
>   ocfs2: dir,refcounttree,xattr: replace swap functions with built-in
>     one
>   ubifs: find.c: replace swap function with built-in one
>   Lib: sort.h: replace int size with size_t size in the swap function
> 
>  arch/arc/kernel/unwind.c        | 20 ++------------------
>  arch/powerpc/kernel/module_32.c | 17 +----------------
>  arch/powerpc/kernel/module_64.c | 17 +----------------
>  arch/x86/kernel/unwind_orc.c    |  2 +-
>  fs/ocfs2/dir.c                  | 13 +------------
>  fs/ocfs2/refcounttree.c         | 13 +++----------
>  fs/ocfs2/xattr.c                | 15 +++------------
>  fs/ubifs/find.c                 |  9 +--------
>  include/linux/sort.h            |  2 +-
>  kernel/jump_label.c             |  2 +-
>  lib/extable.c                   |  2 +-
>  lib/sort.c                      |  6 +++---
>  12 files changed, 19 insertions(+), 99 deletions(-)
> 
> -- 
> 2.21.0
> 
> 

-- 
With Best Regards,
Andy Shevchenko