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2015-04-15.mailmap: add Ricardo RibaldaRicardo Ribalda Delgado
Work and Home computer had different settings in the mail client. Some contributions appear as Ricardo Ribalda, others as Ricardo Ribalda Delgado (and one as just Ricardo). Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15CREDITS: add Ricardo Ribalda DelgadoRicardo Ribalda Delgado
Add personal details to CREDITS file. Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15MAINTAINERS: Use tabs consistentlyJoe Perches
Consistently use a single tab after the "specifier:" type. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/string_helpers.c: change semantics of string_escape_memRasmus Villemoes
The current semantics of string_escape_mem are inadequate for one of its current users, vsnprintf(). If that is to honour its contract, it must know how much space would be needed for the entire escaped buffer, and string_escape_mem provides no way of obtaining that (short of allocating a large enough buffer (~4 times input string) to let it play with, and that's definitely a big no-no inside vsnprintf). So change the semantics for string_escape_mem to be more snprintf-like: Return the size of the output that would be generated if the destination buffer was big enough, but of course still only write to the part of dst it is allowed to, and (contrary to snprintf) don't do '\0'-termination. It is then up to the caller to detect whether output was truncated and to append a '\0' if desired. Also, we must output partial escape sequences, otherwise a call such as snprintf(buf, 3, "%1pE", "\123") would cause printf to write a \0 to buf[2] but leaving buf[0] and buf[1] with whatever they previously contained. This also fixes a bug in the escaped_string() helper function, which used to unconditionally pass a length of "end-buf" to string_escape_mem(); since the latter doesn't check osz for being insanely large, it would happily write to dst. For example, kasprintf(GFP_KERNEL, "something and then %pE", ...); is an easy way to trigger an oops. In test-string_helpers.c, the -ENOMEM test is replaced with testing for getting the expected return value even if the buffer is too small. We also ensure that nothing is written (by relying on a NULL pointer deref) if the output size is 0 by passing NULL - this has to work for kasprintf("%pE") to work. In net/sunrpc/cache.c, I think qword_add still has the same semantics. Someone should definitely double-check this. In fs/proc/array.c, I made the minimum possible change, but longer-term it should stop poking around in seq_file internals. [andriy.shevchenko@linux.intel.com: simplify qword_add] [andriy.shevchenko@linux.intel.com: add missed curly braces] Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/string_helpers.c: refactor string_escape_memRasmus Villemoes
When printf is given the format specifier %pE, it needs a way of obtaining the total output size that would be generated if the buffer was large enough, and string_escape_mem doesn't easily provide that. This is a refactorization of string_escape_mem in preparation of changing its external API to provide that information. The somewhat ugly early returns and subsequent seemingly redundant conditionals are to make the following patch touch as little as possible in string_helpers.c while still preserving the current behaviour of never outputting partial escape sequences. That behaviour must also change for %pE to work as one expects from every other printf specifier. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/vsprintf.c: fix potential NULL deref in hex_stringRasmus Villemoes
The helper hex_string() is broken in two ways. First, it doesn't increment buf regardless of whether there is room to print, so callers such as kasprintf() that try to probe the correct storage to allocate will get a too small return value. But even worse, kasprintf() (and likely anyone else trying to find the size of the result) pass NULL for buf and 0 for size, so we also have end == NULL. But this means that the end-1 in hex_string() is (char*)-1, so buf < end-1 is true and we get a NULL pointer deref. I double-checked this with a trivial kernel module that just did a kasprintf(GFP_KERNEL, "%14ph", "CrashBoomBang"). Nobody seems to be using %ph with kasprintf, but we might as well fix it before it hits someone. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/vsprintf: add %pC{,n,r} format specifiers for clocksGeert Uytterhoeven
Add format specifiers for printing struct clk: - '%pC' or '%pCn': name (Common Clock Framework) or address (legacy clock framework) of the clock, - '%pCr': rate of the clock. [akpm@linux-foundation.org: omit code if !CONFIG_HAVE_CLK] Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Turquette <mturquette@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/vsprintf: Move integer format types to the topGeert Uytterhoeven
Move the format types for 64-bit integers and configurable size integers to the top, so they're next to the other integer format types. While at it, add the missing format types for s32 and u32. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Turquette <mturquette@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/vsprintf: document %p parameters passed by referenceGeert Uytterhoeven
This patch series improves the documentation for printk() formats, and adds support for printing clocks. The latter has always been a hassle if you wanted to support both the common and legacy clock frameworks. - '%pC' and '%pCn' print the name (Common Clock Framework) or address (legacy clock framework) of a clock, - '%pCr' prints the current clock rate. This patch (of 3): Make sure all %p extensions that take parameters by references are documented to do so. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Turquette <mturquette@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/vsprintf.c: another small hackRasmus Villemoes
Making ZEROPAD == '0'-' ', we can eliminate a few more instructions. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/vsprintf.c: eliminate duplicate hex string arrayRasmus Villemoes
gcc doesn't merge or overlap const char[] objects with identical contents (probably language lawyers would also insist that these things have different addresses), but there's no reason to have the string "0123456789ABCDEF" occur in multiple places. hex_asc_upper is declared in kernel.h and defined in lib/hexdump.c, which is unconditionally compiled in. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/vsprintf.c: reduce stack use in number()Rasmus Villemoes
At least since the initial git commit, when base was passed as a separate parameter, number() has only been called with bases 8, 10 and 16. I'm guessing that 66 was to accommodate 64 0/1, a sign and a '\0', but the buffer is only used for the actual digits. Octal digits carry 3 bits of information, so 24 is enough. Spell that 3*sizeof(num) so one less place needs to be changed should long long ever be 128 bits. Also remove the commented-out code that would handle an arbitrary base. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/vsprintf.c: eliminate some branchesRasmus Villemoes
Since FORMAT_TYPE_INT is simply 1 more than FORMAT_TYPE_UINT, and similarly for BYTE/UBYTE, SHORT/USHORT, LONG/ULONG, we can eliminate a few instructions by making SIGN have the value 1 instead of 2, and then use arithmetic instead of branches for computing the right spec->type. It's a little hacky, but certainly in the same spirit as SMALL needing to have the value 0x20. For example for the spec->qualifier == 'l' case, gcc now generates 75e: 0f b6 53 01 movzbl 0x1(%rbx),%edx 762: 83 e2 01 and $0x1,%edx 765: 83 c2 09 add $0x9,%edx 768: 88 13 mov %dl,(%rbx) instead of 763: 0f b6 53 01 movzbl 0x1(%rbx),%edx 767: 83 e2 02 and $0x2,%edx 76a: 80 fa 01 cmp $0x1,%dl 76d: 19 d2 sbb %edx,%edx 76f: 83 c2 0a add $0xa,%edx 772: 88 13 mov %dl,(%rbx) Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15printk: comment pr_cont() stating it is only to continue a lineSteven Rostedt
KERN_CONT is nicely commented in kern_levels.h, but pr_cont() is now used more often, and it lacks the comment stating what it is used for. It can be confused as continuing the log level, but that is not its purpose. Its purpose is to continue a line that had no newline enclosed. This should be documented by pr_cont() as well. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Borislav Petkov <bp@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15powerpc/powernv: reboot when requested by firmwareJoel Stanley
Use orderly_reboot so userspace will to shut itself down via the reboot path. This is required for graceful reboot initiated by the BMC, such as when a user uses ipmitool to issue a 'chassis power cycle' command. Signed-off-by: Joel Stanley <joel@jms.id.au> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Fabian Frederick <fabf@skynet.be> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15kernel/reboot.c: add orderly_reboot for graceful rebootJoel Stanley
The kernel has orderly_poweroff which allows the kernel to initiate a graceful shutdown of userspace, by running /sbin/poweroff. This adds orderly_reboot that will cause userspace to shut itself down by calling /sbin/reboot. This will be used for shutdown initiated by a system controller on platforms that do not use ACPI. orderly_reboot() should be used when the system wants to allow userspace to gracefully shut itself down. For cases where the system may imminently catch on fire, the existing emergency_restart() provides an immediate reboot without involving userspace. Signed-off-by: Joel Stanley <joel@jms.id.au> Cc: Fabian Frederick <fabf@skynet.be> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15drivers/sbus/char/envctrl.c: ignore orderly_poweroff return valueJoel Stanley
orderly_poweroff() unconditionally returns 0, so remove the dead code that checks the return value. A future patch will change the return type to void. Signed-off-by: Joel Stanley <joel@jms.id.au> Acked-by: David S. Miller <davem@davemloft.net> Cc: Fabian Frederick <fabf@skynet.be> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Kerr <jk@ozlabs.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15kernel/hung_task.c: change hung_task.c to use for_each_process_thread()Aaron Tomlin
In check_hung_uninterruptible_tasks() avoid the use of deprecated while_each_thread(). The "max_count" logic will prevent a livelock - see commit 0c740d0a ("introduce for_each_thread() to replace the buggy while_each_thread()"). Having said this let's use for_each_process_thread(). Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Dave Wysochanski <dwysocha@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15kernel/resource.c: remove deprecated __check_region() and friendsJakub Sitnicki
All users of __check_region(), check_region(), and check_mem_region() are gone. We got rid of the last user in v4.0-rc1. Remove them. bloat-o-meter on x86_64 shows: add/remove: 0/3 grow/shrink: 0/0 up/down: 0/-102 (-102) function old new delta __kstrtab___check_region 15 - -15 __ksymtab___check_region 16 - -16 __check_region 71 - -71 Signed-off-by: Jakub Sitnicki <jsitnicki@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15kernel: conditionally support non-root users, groups and capabilitiesIulia Manda
There are a lot of embedded systems that run most or all of their functionality in init, running as root:root. For these systems, supporting multiple users is not necessary. This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for non-root users, non-root groups, and capabilities optional. It is enabled under CONFIG_EXPERT menu. When this symbol is not defined, UID and GID are zero in any possible case and processes always have all capabilities. The following syscalls are compiled out: setuid, setregid, setgid, setreuid, setresuid, getresuid, setresgid, getresgid, setgroups, getgroups, setfsuid, setfsgid, capget, capset. Also, groups.c is compiled out completely. In kernel/capability.c, capable function was moved in order to avoid adding two ifdef blocks. This change saves about 25 KB on a defconfig build. The most minimal kernels have total text sizes in the high hundreds of kB rather than low MB. (The 25k goes down a bit with allnoconfig, but not that much. The kernel was booted in Qemu. All the common functionalities work. Adding users/groups is not possible, failing with -ENOSYS. Bloat-o-meter output: add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650) [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Iulia Manda <iulia.manda21@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15lib/test-hexdump.c: fix initconst confusionAndi Kleen
const char *...[] is not const, but an array of pointer to const. So these arrays cannot be __initconst, but must be __initdata This fixes section conflicts with LTO. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15paride: fix the "verbose" module paramDan Carpenter
The verbose module parameter can be set to 2 for extremely verbose messages so the type should be int instead of bool. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Tim Waugh <tim@cyberelk.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15include/linux: remove empty conditionalsRasmus Villemoes
Commit 607ca46e97a1 ("UAPI: (Scripted) Disintegrate include/linux") left behind some empty conditional blocks. Since they are useless and may cause a reader to wonder whether something is missing, remove them. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15/proc/PID/status: show all sets of pid according to nsChen Hanxiao
If some issues occurred inside a container guest, host user could not know which process is in trouble just by guest pid: the users of container guest only knew the pid inside containers. This will bring obstacle for trouble shooting. This patch adds four fields: NStgid, NSpid, NSpgid and NSsid: a) In init_pid_ns, nothing changed; b) In one pidns, will tell the pid inside containers: NStgid: 21776 5 1 NSpid: 21776 5 1 NSpgid: 21776 5 1 NSsid: 21729 1 0 ** Process id is 21776 in level 0, 5 in level 1, 1 in level 2. c) If pidns is nested, it depends on which pidns are you in. NStgid: 5 1 NSpid: 5 1 NSpgid: 5 1 NSsid: 1 0 ** Views from level 1 [akpm@linux-foundation.org: add CONFIG_PID_NS ifdef] Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Tested-by: Serge Hallyn <serge.hallyn@canonical.com> Tested-by: Nathan Scott <nathans@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: fix error return codeJulia Lawall
Return a negative error code on failure. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ identifier ret; expression e1,e2; @@ ( if (\(ret < 0\|ret != 0\)) { ... return ret; } | ret = 0 ) ... when != ret = e1 when != &ret *if(...) { ... when != ret = e2 when forall return ret; } // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Acked-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: remove extra cond_resched() in __zs_compactSergey Senozhatsky
Do not perform cond_resched() before the busy compaction loop in __zs_compact(), because this loop does it when needed. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: fix fatal corruption due to wrong size class selectionHeesub Shin
There is no point in overriding the size class below. It causes fatal corruption on the next chunk on the 3264-bytes size class, which is the last size class that is not huge. For example, if the requested size was exactly 3264 bytes, current zsmalloc allocates and returns a chunk from the size class of 3264 bytes, not 4096. User access to this chunk may overwrite head of the next adjacent chunk. Here is the panic log captured when freelist was corrupted due to this: Kernel BUG at ffffffc00030659c [verbose debug info unavailable] Internal error: Oops - BUG: 96000006 [#1] PREEMPT SMP Modules linked in: exynos-snapshot: core register saved(CPU:5) CPUMERRSR: 0000000000000000, L2MERRSR: 0000000000000000 exynos-snapshot: context saved(CPU:5) exynos-snapshot: item - log_kevents is disabled CPU: 5 PID: 898 Comm: kswapd0 Not tainted 3.10.61-4497415-eng #1 task: ffffffc0b8783d80 ti: ffffffc0b71e8000 task.ti: ffffffc0b71e8000 PC is at obj_idx_to_offset+0x0/0x1c LR is at obj_malloc+0x44/0xe8 pc : [<ffffffc00030659c>] lr : [<ffffffc000306604>] pstate: a0000045 sp : ffffffc0b71eb790 x29: ffffffc0b71eb790 x28: ffffffc00204c000 x27: 000000000001d96f x26: 0000000000000000 x25: ffffffc098cc3500 x24: ffffffc0a13f2810 x23: ffffffc098cc3501 x22: ffffffc0a13f2800 x21: 000011e1a02006e3 x20: ffffffc0a13f2800 x19: ffffffbc02a7e000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000feb x15: 0000000000000000 x14: 00000000a01003e3 x13: 0000000000000020 x12: fffffffffffffff0 x11: ffffffc08b264000 x10: 00000000e3a01004 x9 : ffffffc08b263fea x8 : ffffffc0b1e611c0 x7 : ffffffc000307d24 x6 : 0000000000000000 x5 : 0000000000000038 x4 : 000000000000011e x3 : ffffffbc00003e90 x2 : 0000000000000cc0 x1 : 00000000d0100371 x0 : ffffffbc00003e90 Reported-by: Sooyong Suk <s.suk@samsung.com> Signed-off-by: Heesub Shin <heesub.shin@samsung.com> Tested-by: Sooyong Suk <s.suk@samsung.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: remove unnecessary insertion/removal of zspage in compactionMinchan Kim
In putback_zspage, we don't need to insert a zspage into list of zspage in size_class again to just fix fullness group. We could do directly without reinsertion so we could save some instuctions. Reported-by: Heesub Shin <heesub.shin@samsung.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Ganesh Mahendran <opensource.ganesh@gmail.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Juneho Choi <juno.choi@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: micro-optimize zs_object_copy()Sergey Senozhatsky
A micro-optimization. Avoid additional branching and reduce (a bit) registry pressure (f.e. s_off += size; d_off += size; may be calculated twise: first for >= PAGE_SIZE check and later for offset update in "else" clause). scripts/bloat-o-meter shows some improvement add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-10 (-10) function old new delta zs_object_copy 550 540 -10 Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: remove synchronize_rcu from zs_compact()Sergey Senozhatsky
Do not synchronize rcu in zs_compact(). Neither zsmalloc not zram use rcu. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: deprecate zram attrs sysfs nodesSergey Senozhatsky
Add Documentation/ABI/obsolete/sysfs-block-zram file and list obsolete and deprecated attributes there. The patch also adds additional information to zram documentation and describes the basic strategy: - the existing RW nodes will be downgraded to WO nodes (in 4.11) - deprecated RO sysfs nodes will eventually be removed (in 4.11) Users will be additionally notified about deprecated attr usage by pr_warn_once() (added to every deprecated attr _show()), as suggested by Minchan Kim. User space is advised to use zram<id>/stat, zram<id>/io_stat and zram<id>/mm_stat files. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: export new 'mm_stat' sysfs attrsSergey Senozhatsky
Per-device `zram<id>/mm_stat' file provides mm statistics of a particular zram device in a format similar to block layer statistics. The file consists of a single line and represents the following stats (separated by whitespace): orig_data_size compr_data_size mem_used_total mem_limit mem_used_max zero_pages num_migrated Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: export new 'io_stat' sysfs attrsSergey Senozhatsky
Per-device `zram<id>/io_stat' file provides accumulated I/O statistics of particular zram device in a format similar to block layer statistics. The file consists of a single line and represents the following stats (separated by whitespace): failed_reads failed_writes invalid_io notify_free Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: describe device attrs in documentationSergey Senozhatsky
Briefly describe exported device stat attrs in zram documentation. We will eventually get rid of per-stat sysfs nodes and, thus, clean up Documentation/ABI/testing/sysfs-block-zram file, which is the only source of information about device sysfs nodes. Add `num_migrated' description, since there is no independent `num_migrated' sysfs node (and no corresponding sysfs-block-zram entry), it will be exported via zram<id>/mm_stat file. At this point we can provide minimal description, because sysfs-block-zram still contains detailed information. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: use generic start/end io accountingSergey Senozhatsky
Use bio generic_start_io_acct() and generic_end_io_acct() to account device's block layer statistics. This will let users to monitor zram activities using sysstat and similar packages/tools. Apart from the usual per-stat sysfs attr, zram IO stats are now also available in '/sys/block/zram<id>/stat' and '/proc/diskstats' files. We will slowly get rid of per-stat sysfs files. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: move compact_store() to sysfs functions areaSergey Senozhatsky
A cosmetic change. We have a new code layout and keep zram per-device sysfs store and show functions in one place. Move compact_store() to that handlers block to conform to current layout. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: remove `num_migrated' device attrSergey Senozhatsky
This patch introduces rework to zram stats. We have per-stat sysfs nodes, and it makes things a bit hard to use in user space: it doesn't give an immediate stats 'snapshot', it requires user space to use more syscalls - open, read, close for every stat file, with appropriate error checks on every step, etc. First, zram now accounts block layer statistics, available in /sys/block/zram<id>/stat and /proc/diskstats files. So some new stats are available (see Documentation/block/stat.txt), besides, zram's activities now can be monitored by sysstat's iostat or similar tools. Example: cat /sys/block/zram0/stat 248 0 1984 0 251029 0 2008232 5120 0 5116 5116 Second, group currently exported on per-stat basis nodes into two categories (files): -- zram<id>/io_stat accumulates device's IO stats, that are not accounted by block layer, and contains: failed_reads failed_writes invalid_io notify_free Example: cat /sys/block/zram0/io_stat 0 0 0 652572 -- zram<id>/mm_stat accumulates zram mm stats and contains: orig_data_size compr_data_size mem_used_total mem_limit mem_used_max zero_pages num_migrated Example: cat /sys/block/zram0/mm_stat 434634752 270288572 279158784 0 579895296 15060 0 per-stat sysfs nodes are now considered to be deprecated and we plan to remove them (and clean up some of the existing stat code) in two years (as of now, there is no warning printed to syslog about deprecated stats being used). User space is advised to use the above mentioned 3 files. This patch (of 7): Remove sysfs `num_migrated' attribute. We are moving away from per-stat device attrs towards 3 stat files that will accumulate io and mm stats in a format similar to block layer statistics in /sys/block/<dev>/stat. That will be easier to use in user space, and reduce the number of syscalls needed to read zram device statistics. `num_migrated' will return back in zram<id>/mm_stat file. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15mm/zsmalloc.c: fix comment for get_pages_per_zspageYinghao Xie
Signed-off-by: Yinghao Xie <yinghao.xie@sumsung.com> Suggested-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: zsmalloc documentationMinchan Kim
Create zsmalloc doc which explains design concept and stat information. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: add fullness into statMinchan Kim
During investigating compaction, fullness information of each class is helpful for investigating how the compaction works well. With that, we could know how compaction works well more clear on each size class. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: record handle in page->private for huge objectMinchan Kim
We store handle on header of each allocated object so it increases the size of each object by sizeof(unsigned long). If zram stores 4096 bytes to zsmalloc(ie, bad compression), zsmalloc needs 4104B-class to add handle. However, 4104B-class has 1-pages_per_zspage so wasted size by internal fragment is 8192 - 4104, which is terrible. So this patch records the handle in page->private on such huge object(ie, pages_per_zspage == 1 && maxobj_per_zspage == 1) instead of header of each object so we could use 4096B-class, not 4104B-class. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zram: support compactionMinchan Kim
Now that zsmalloc supports compaction, zram can use it. For the first step, this patch exports compact knob via sysfs so user can do compaction via "echo 1 > /sys/block/zram0/compact". Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: adjust ZS_ALMOST_FULLMinchan Kim
Curretly, zsmalloc regards a zspage as ZS_ALMOST_EMPTY if the zspage has under 1/4 used objects(ie, fullness_threshold_frac). It could make result in loose packing since zsmalloc migrates only ZS_ALMOST_EMPTY zspage out. This patch changes the rule so that zsmalloc makes zspage which has above 3/4 used object ZS_ALMOST_FULL so it could make tight packing. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: support compactionMinchan Kim
This patch provides core functions for migration of zsmalloc. Migraion policy is simple as follows. for each size class { while { src_page = get zs_page from ZS_ALMOST_EMPTY if (!src_page) break; dst_page = get zs_page from ZS_ALMOST_FULL if (!dst_page) dst_page = get zs_page from ZS_ALMOST_EMPTY if (!dst_page) break; migrate(from src_page, to dst_page); } } For migration, we need to identify which objects in zspage are allocated to migrate them out. We could know it by iterating of freed objects in a zspage because first_page of zspage keeps free objects singly-linked list but it's not efficient. Instead, this patch adds a tag(ie, OBJ_ALLOCATED_TAG) in header of each object(ie, handle) so we could check whether the object is allocated easily. This patch adds another status bit in handle to synchronize between user access through zs_map_object and migration. During migration, we cannot move objects user are using due to data coherency between old object and new object. [akpm@linux-foundation.org: zsmalloc.c needs sched.h for cond_resched()] Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: factor out obj_[malloc|free]Minchan Kim
In later patch, migration needs some part of functions in zs_malloc and zs_free so this patch factor out them. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15zsmalloc: decouple handle and objectMinchan Kim
Recently, we started to use zram heavily and some of issues popped. 1) external fragmentation I got a report from Juneho Choi that fork failed although there are plenty of free pages in the system. His investigation revealed zram is one of the culprit to make heavy fragmentation so there was no more contiguous 16K page for pgd to fork in the ARM. 2) non-movable pages Other problem of zram now is that inherently, user want to use zram as swap in small memory system so they use zRAM with CMA to use memory efficiently. However, unfortunately, it doesn't work well because zRAM cannot use CMA's movable pages unless it doesn't support compaction. I got several reports about that OOM happened with zram although there are lots of swap space and free space in CMA area. 3) internal fragmentation zRAM has started support memory limitation feature to limit memory usage and I sent a patchset(https://lkml.org/lkml/2014/9/21/148) for VM to be harmonized with zram-swap to stop anonymous page reclaim if zram consumed memory up to the limit although there are free space on the swap. One problem for that direction is zram has no way to know any hole in memory space zsmalloc allocated by internal fragmentation so zram would regard swap is full although there are free space in zsmalloc. For solving the issue, zram want to trigger compaction of zsmalloc before it decides full or not. This patchset is first step to support above issues. For that, it adds indirect layer between handle and object location and supports manual compaction to solve 3th problem first of all. After this patchset got merged, next step is to make VM aware of zsmalloc compaction so that generic compaction will move zsmalloced-pages automatically in runtime. In my imaginary experiment(ie, high compress ratio data with heavy swap in/out on 8G zram-swap), data is as follows, Before = zram allocated object : 60212066 bytes zram total used: 140103680 bytes ratio: 42.98 percent MemFree: 840192 kB Compaction After = frag ratio after compaction zram allocated object : 60212066 bytes zram total used: 76185600 bytes ratio: 79.03 percent MemFree: 901932 kB Juneho reported below in his real platform with small aging. So, I think the benefit would be bigger in real aging system for a long time. - frag_ratio increased 3% (ie, higher is better) - memfree increased about 6MB - In buddy info, Normal 2^3: 4, 2^2: 1: 2^1 increased, Highmem: 2^1 21 increased frag ratio after swap fragment used : 156677 kbytes total: 166092 kbytes frag_ratio : 94 meminfo before compaction MemFree: 83724 kB Node 0, zone Normal 13642 1364 57 10 61 17 9 5 4 0 0 Node 0, zone HighMem 425 29 1 0 0 0 0 0 0 0 0 num_migrated : 23630 compaction done frag ratio after compaction used : 156673 kbytes total: 160564 kbytes frag_ratio : 97 meminfo after compaction MemFree: 89060 kB Node 0, zone Normal 14076 1544 67 14 61 17 9 5 4 0 0 Node 0, zone HighMem 863 50 1 0 0 0 0 0 0 0 0 This patchset adds more logics(about 480 lines) in zsmalloc but when I tested heavy swapin/out program, the regression for swapin/out speed is marginal because most of overheads were caused by compress/decompress and other MM reclaim stuff. This patch (of 7): Currently, handle of zsmalloc encodes object's location directly so it makes support of migration hard. This patch decouples handle and object via adding indirect layer. For that, it allocates handle dynamically and returns it to user. The handle is the address allocated by slab allocation so it's unique and we could keep object's location in the memory space allocated for handle. With it, we can change object's position without changing handle itself. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15mm/compaction.c: fix "suitable_migration_target() unused" warningAndrew Morton
mm/compaction.c:250:13: warning: 'suitable_migration_target' defined but not used [-Wunused-function] Reported-by: Fengguang Wu <fengguang.wu@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15dax: unify ext2/4_{dax,}_file_operationsBoaz Harrosh
The original dax patchset split the ext2/4_file_operations because of the two NULL splice_read/splice_write in the dax case. In the vfs if splice_read/splice_write are NULL we then call default_splice_read/write. What we do here is make generic_file_splice_read aware of IS_DAX() so the original ext2/4_file_operations can be used as is. For write it appears that iter_file_splice_write is just fine. It uses the regular f_op->write(file,..) or new_sync_write(file, ...). Signed-off-by: Boaz Harrosh <boaz@plexistor.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Dave Chinner <dchinner@redhat.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15dax: use pfn_mkwrite to update c/mtime + freeze protectionBoaz Harrosh
From: Yigal Korman <yigal@plexistor.com> [v1] Without this patch, c/mtime is not updated correctly when mmap'ed page is first read from and then written to. A new xfstest is submitted for testing this (generic/080) [v2] Jan Kara has pointed out that if we add the sb_start/end_pagefault pair in the new pfn_mkwrite we are then fixing another bug where: A user could start writing to the page while filesystem is frozen. Signed-off-by: Yigal Korman <yigal@plexistor.com> Signed-off-by: Boaz Harrosh <boaz@plexistor.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15mm: new pfn_mkwrite same as page_mkwrite for VM_PFNMAPBoaz Harrosh
This will allow FS that uses VM_PFNMAP | VM_MIXEDMAP (no page structs) to get notified when access is a write to a read-only PFN. This can happen if we mmap() a file then first mmap-read from it to page-in a read-only PFN, than we mmap-write to the same page. We need this functionality to fix a DAX bug, where in the scenario above we fail to set ctime/mtime though we modified the file. An xfstest is attached to this patchset that shows the failure and the fix. (A DAX patch will follow) This functionality is extra important for us, because upon dirtying of a pmem page we also want to RDMA the page to a remote cluster node. We define a new pfn_mkwrite and do not reuse page_mkwrite because 1 - The name ;-) 2 - But mainly because it would take a very long and tedious audit of all page_mkwrite functions of VM_MIXEDMAP/VM_PFNMAP users. To make sure they do not now CRASH. For example current DAX code (which this is for) would crash. If we would want to reuse page_mkwrite, We will need to first patch all users, so to not-crash-on-no-page. Then enable this patch. But even if I did that I would not sleep so well at night. Adding a new vector is the safest thing to do, and is not that expensive. an extra pointer at a static function vector per driver. Also the new vector is better for performance, because else we Will call all current Kernel vectors, so to: check-ha-no-page-do-nothing and return. No need to call it from do_shared_fault because do_wp_page is called to change pte permissions anyway. Signed-off-by: Yigal Korman <yigal@plexistor.com> Signed-off-by: Boaz Harrosh <boaz@plexistor.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>