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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Matthew Wilcox <mawilcox@microsoft.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	David Miller <davem@davemloft.net>, Ingo Molnar <mingo@elte.hu>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	Matt Turner <mattst88@gmail.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Minchan Kim <minchan@kernel.org>,
	Ralf Baechle <ralf@linux-mips.org>,
	Richard Henderson <rth@twiddle.net>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	Sam Ravnborg <sam@ravnborg.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Nobuhiro Iwamatsu (CIP)" <nobuhiro1.iwamatsu@toshiba.co.jp>
Subject: [PATCH 4.9 13/32] lib/string.c: add multibyte memset functions
Date: Mon,  2 Aug 2021 15:44:33 +0200	[thread overview]
Message-ID: <20210802134333.346882923@linuxfoundation.org> (raw)
In-Reply-To: <20210802134332.931915241@linuxfoundation.org>

From: Matthew Wilcox <mawilcox@microsoft.com>

commit 3b3c4babd898715926d24ae10aa64778ace33aae upstream.

Patch series "Multibyte memset variations", v4.

A relatively common idiom we're missing is a function to fill an area of
memory with a pattern which is larger than a single byte.  I first
noticed this with a zram patch which wanted to fill a page with an
'unsigned long' value.  There turn out to be quite a few places in the
kernel which can benefit from using an optimised function rather than a
loop; sometimes text size, sometimes speed, and sometimes both.  The
optimised PowerPC version (not included here) improves performance by
about 30% on POWER8 on just the raw memset_l().

Most of the extra lines of code come from the three testcases I added.

This patch (of 8):

memset16(), memset32() and memset64() are like memset(), but allow the
caller to fill the destination with a value larger than a single byte.
memset_l() and memset_p() allow the caller to use unsigned long and
pointer values respectively.

Link: http://lkml.kernel.org/r/20170720184539.31609-2-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/string.h |   30 ++++++++++++++++++++++
 lib/string.c           |   66 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 96 insertions(+)

--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -103,6 +103,36 @@ extern __kernel_size_t strcspn(const cha
 #ifndef __HAVE_ARCH_MEMSET
 extern void * memset(void *,int,__kernel_size_t);
 #endif
+
+#ifndef __HAVE_ARCH_MEMSET16
+extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
+#endif
+
+#ifndef __HAVE_ARCH_MEMSET32
+extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
+#endif
+
+#ifndef __HAVE_ARCH_MEMSET64
+extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
+#endif
+
+static inline void *memset_l(unsigned long *p, unsigned long v,
+		__kernel_size_t n)
+{
+	if (BITS_PER_LONG == 32)
+		return memset32((uint32_t *)p, v, n);
+	else
+		return memset64((uint64_t *)p, v, n);
+}
+
+static inline void *memset_p(void **p, void *v, __kernel_size_t n)
+{
+	if (BITS_PER_LONG == 32)
+		return memset32((uint32_t *)p, (uintptr_t)v, n);
+	else
+		return memset64((uint64_t *)p, (uintptr_t)v, n);
+}
+
 #ifndef __HAVE_ARCH_MEMCPY
 extern void * memcpy(void *,const void *,__kernel_size_t);
 #endif
--- a/lib/string.c
+++ b/lib/string.c
@@ -754,6 +754,72 @@ void memzero_explicit(void *s, size_t co
 }
 EXPORT_SYMBOL(memzero_explicit);
 
+#ifndef __HAVE_ARCH_MEMSET16
+/**
+ * memset16() - Fill a memory area with a uint16_t
+ * @s: Pointer to the start of the area.
+ * @v: The value to fill the area with
+ * @count: The number of values to store
+ *
+ * Differs from memset() in that it fills with a uint16_t instead
+ * of a byte.  Remember that @count is the number of uint16_ts to
+ * store, not the number of bytes.
+ */
+void *memset16(uint16_t *s, uint16_t v, size_t count)
+{
+	uint16_t *xs = s;
+
+	while (count--)
+		*xs++ = v;
+	return s;
+}
+EXPORT_SYMBOL(memset16);
+#endif
+
+#ifndef __HAVE_ARCH_MEMSET32
+/**
+ * memset32() - Fill a memory area with a uint32_t
+ * @s: Pointer to the start of the area.
+ * @v: The value to fill the area with
+ * @count: The number of values to store
+ *
+ * Differs from memset() in that it fills with a uint32_t instead
+ * of a byte.  Remember that @count is the number of uint32_ts to
+ * store, not the number of bytes.
+ */
+void *memset32(uint32_t *s, uint32_t v, size_t count)
+{
+	uint32_t *xs = s;
+
+	while (count--)
+		*xs++ = v;
+	return s;
+}
+EXPORT_SYMBOL(memset32);
+#endif
+
+#ifndef __HAVE_ARCH_MEMSET64
+/**
+ * memset64() - Fill a memory area with a uint64_t
+ * @s: Pointer to the start of the area.
+ * @v: The value to fill the area with
+ * @count: The number of values to store
+ *
+ * Differs from memset() in that it fills with a uint64_t instead
+ * of a byte.  Remember that @count is the number of uint64_ts to
+ * store, not the number of bytes.
+ */
+void *memset64(uint64_t *s, uint64_t v, size_t count)
+{
+	uint64_t *xs = s;
+
+	while (count--)
+		*xs++ = v;
+	return s;
+}
+EXPORT_SYMBOL(memset64);
+#endif
+
 #ifndef __HAVE_ARCH_MEMCPY
 /**
  * memcpy - Copy one area of memory to another



  parent reply	other threads:[~2021-08-02 13:51 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 13:44 [PATCH 4.9 00/32] 4.9.278-rc1 review Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 01/32] iommu/amd: Fix backport of 140456f994195b568ecd7fc2287a34eadffef3ca Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 02/32] tipc: Fix backport of b77413446408fdd256599daf00d5be72b5f3e7c6 Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 03/32] net: split out functions related to registering inflight socket files Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 04/32] af_unix: fix garbage collect vs MSG_PEEK Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 05/32] workqueue: fix UAF in pwq_unbound_release_workfn() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 06/32] net/802/mrp: fix memleak in mrp_request_join() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 07/32] net/802/garp: fix memleak in garp_request_join() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 08/32] sctp: move 198 addresses from unusable to private scope Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 09/32] hfs: add missing clean-up in hfs_fill_super Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 10/32] hfs: fix high memory mapping in hfs_bnode_read Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 11/32] hfs: add lock nesting notation to hfs_find_init Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 12/32] ARM: dts: versatile: Fix up interrupt controller node names Greg Kroah-Hartman
2021-08-02 13:44 ` Greg Kroah-Hartman [this message]
2021-08-02 13:44 ` [PATCH 4.9 14/32] ARM: ensure the signal page contains defined contents Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 15/32] x86/kvm: fix vcpu-id indexed array sizes Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 16/32] ocfs2: fix zero out valid data Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 17/32] ocfs2: issue zeroout to EOF blocks Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 18/32] can: usb_8dev: fix memory leak Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 19/32] can: ems_usb: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 20/32] can: esd_usb2: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 21/32] NIU: fix incorrect error return, missed in previous revert Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 22/32] nfc: nfcsim: fix use after free during module unload Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 23/32] x86/asm: Ensure asm/proto.h can be included stand-alone Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 24/32] cfg80211: Fix possible memory leak in function cfg80211_bss_update Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 25/32] netfilter: conntrack: adjust stop timestamp to real expiry value Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 26/32] netfilter: nft_nat: allow to specify layer 4 protocol NAT only Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 27/32] tipc: fix sleeping in tipc accept routine Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 28/32] mlx4: Fix missing error code in mlx4_load_one() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 29/32] net: llc: fix skb_over_panic Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 30/32] net/mlx5: Fix flow table chaining Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 31/32] tulip: windbond-840: Fix missing pci_disable_device() in probe and remove Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.9 32/32] sis900: " Greg Kroah-Hartman
2021-08-03 13:45 ` [PATCH 4.9 00/32] 4.9.278-rc1 review Naresh Kamboju
2021-08-03 19:14 ` Guenter Roeck

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