--- /dev/null
+From 3c3b04d10ff1811a27f86684ccd2f5ba6983211d Mon Sep 17 00:00:00 2001
+From: David Sterba <dsterba@suse.cz>
+Date: Wed, 25 Mar 2015 19:26:41 +0100
+Subject: btrfs: don't accept bare namespace as a valid xattr
+
+From: David Sterba <dsterba@suse.cz>
+
+commit 3c3b04d10ff1811a27f86684ccd2f5ba6983211d upstream.
+
+Due to insufficient check in btrfs_is_valid_xattr, this unexpectedly
+works:
+
+ $ touch file
+ $ setfattr -n user. -v 1 file
+ $ getfattr -d file
+user.="1"
+
+ie. the missing attribute name after the namespace.
+
+Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=94291
+Reported-by: William Douglas <william.douglas@intel.com>
+Signed-off-by: David Sterba <dsterba@suse.cz>
+Signed-off-by: Chris Mason <clm@fb.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/btrfs/xattr.c | 53 +++++++++++++++++++++++++++++++++++++++--------------
+ 1 file changed, 39 insertions(+), 14 deletions(-)
+
+--- a/fs/btrfs/xattr.c
++++ b/fs/btrfs/xattr.c
+@@ -324,22 +324,42 @@ const struct xattr_handler *btrfs_xattr_
+ /*
+ * Check if the attribute is in a supported namespace.
+ *
+- * This applied after the check for the synthetic attributes in the system
++ * This is applied after the check for the synthetic attributes in the system
+ * namespace.
+ */
+-static bool btrfs_is_valid_xattr(const char *name)
++static int btrfs_is_valid_xattr(const char *name)
+ {
+- return !strncmp(name, XATTR_SECURITY_PREFIX,
+- XATTR_SECURITY_PREFIX_LEN) ||
+- !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
+- !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
+- !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) ||
+- !strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
++ int len = strlen(name);
++ int prefixlen = 0;
++
++ if (!strncmp(name, XATTR_SECURITY_PREFIX,
++ XATTR_SECURITY_PREFIX_LEN))
++ prefixlen = XATTR_SECURITY_PREFIX_LEN;
++ else if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
++ prefixlen = XATTR_SYSTEM_PREFIX_LEN;
++ else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
++ prefixlen = XATTR_TRUSTED_PREFIX_LEN;
++ else if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
++ prefixlen = XATTR_USER_PREFIX_LEN;
++ else if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
++ prefixlen = XATTR_BTRFS_PREFIX_LEN;
++ else
++ return -EOPNOTSUPP;
++
++ /*
++ * The name cannot consist of just prefix
++ */
++ if (len <= prefixlen)
++ return -EINVAL;
++
++ return 0;
+ }
+
+ ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
+ void *buffer, size_t size)
+ {
++ int ret;
++
+ /*
+ * If this is a request for a synthetic attribute in the system.*
+ * namespace use the generic infrastructure to resolve a handler
+@@ -348,8 +368,9 @@ ssize_t btrfs_getxattr(struct dentry *de
+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return generic_getxattr(dentry, name, buffer, size);
+
+- if (!btrfs_is_valid_xattr(name))
+- return -EOPNOTSUPP;
++ ret = btrfs_is_valid_xattr(name);
++ if (ret)
++ return ret;
+ return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
+ }
+
+@@ -357,6 +378,7 @@ int btrfs_setxattr(struct dentry *dentry
+ size_t size, int flags)
+ {
+ struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
++ int ret;
+
+ /*
+ * The permission on security.* and system.* is not checked
+@@ -373,8 +395,9 @@ int btrfs_setxattr(struct dentry *dentry
+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return generic_setxattr(dentry, name, value, size, flags);
+
+- if (!btrfs_is_valid_xattr(name))
+- return -EOPNOTSUPP;
++ ret = btrfs_is_valid_xattr(name);
++ if (ret)
++ return ret;
+
+ if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
+ return btrfs_set_prop(dentry->d_inode, name,
+@@ -390,6 +413,7 @@ int btrfs_setxattr(struct dentry *dentry
+ int btrfs_removexattr(struct dentry *dentry, const char *name)
+ {
+ struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
++ int ret;
+
+ /*
+ * The permission on security.* and system.* is not checked
+@@ -406,8 +430,9 @@ int btrfs_removexattr(struct dentry *den
+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return generic_removexattr(dentry, name);
+
+- if (!btrfs_is_valid_xattr(name))
+- return -EOPNOTSUPP;
++ ret = btrfs_is_valid_xattr(name);
++ if (ret)
++ return ret;
+
+ if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
+ return btrfs_set_prop(dentry->d_inode, name,
--- /dev/null
+From ccccf3d67294714af2d72a6fd6fd7d73b01c9329 Mon Sep 17 00:00:00 2001
+From: Filipe Manana <fdmanana@suse.com>
+Date: Mon, 30 Mar 2015 18:23:59 +0100
+Subject: Btrfs: fix inode eviction infinite loop after cloning into it
+
+From: Filipe Manana <fdmanana@suse.com>
+
+commit ccccf3d67294714af2d72a6fd6fd7d73b01c9329 upstream.
+
+If we attempt to clone a 0 length region into a file we can end up
+inserting a range in the inode's extent_io tree with a start offset
+that is greater then the end offset, which triggers immediately the
+following warning:
+
+[ 3914.619057] WARNING: CPU: 17 PID: 4199 at fs/btrfs/extent_io.c:435 insert_state+0x4b/0x10b [btrfs]()
+[ 3914.620886] BTRFS: end < start 4095 4096
+(...)
+[ 3914.638093] Call Trace:
+[ 3914.638636] [<ffffffff81425fd9>] dump_stack+0x4c/0x65
+[ 3914.639620] [<ffffffff81045390>] warn_slowpath_common+0xa1/0xbb
+[ 3914.640789] [<ffffffffa03ca44f>] ? insert_state+0x4b/0x10b [btrfs]
+[ 3914.642041] [<ffffffff810453f0>] warn_slowpath_fmt+0x46/0x48
+[ 3914.643236] [<ffffffffa03ca44f>] insert_state+0x4b/0x10b [btrfs]
+[ 3914.644441] [<ffffffffa03ca729>] __set_extent_bit+0x107/0x3f4 [btrfs]
+[ 3914.645711] [<ffffffffa03cb256>] lock_extent_bits+0x65/0x1bf [btrfs]
+[ 3914.646914] [<ffffffff8142b2fb>] ? _raw_spin_unlock+0x28/0x33
+[ 3914.648058] [<ffffffffa03cbac4>] ? test_range_bit+0xcc/0xde [btrfs]
+[ 3914.650105] [<ffffffffa03cb3c3>] lock_extent+0x13/0x15 [btrfs]
+[ 3914.651361] [<ffffffffa03db39e>] lock_extent_range+0x3d/0xcd [btrfs]
+[ 3914.652761] [<ffffffffa03de1fe>] btrfs_ioctl_clone+0x278/0x388 [btrfs]
+[ 3914.654128] [<ffffffff811226dd>] ? might_fault+0x58/0xb5
+[ 3914.655320] [<ffffffffa03e0909>] btrfs_ioctl+0xb51/0x2195 [btrfs]
+(...)
+[ 3914.669271] ---[ end trace 14843d3e2e622fc1 ]---
+
+This later makes the inode eviction handler enter an infinite loop that
+keeps dumping the following warning over and over:
+
+[ 3915.117629] WARNING: CPU: 22 PID: 4228 at fs/btrfs/extent_io.c:435 insert_state+0x4b/0x10b [btrfs]()
+[ 3915.119913] BTRFS: end < start 4095 4096
+(...)
+[ 3915.137394] Call Trace:
+[ 3915.137913] [<ffffffff81425fd9>] dump_stack+0x4c/0x65
+[ 3915.139154] [<ffffffff81045390>] warn_slowpath_common+0xa1/0xbb
+[ 3915.140316] [<ffffffffa03ca44f>] ? insert_state+0x4b/0x10b [btrfs]
+[ 3915.141505] [<ffffffff810453f0>] warn_slowpath_fmt+0x46/0x48
+[ 3915.142709] [<ffffffffa03ca44f>] insert_state+0x4b/0x10b [btrfs]
+[ 3915.143849] [<ffffffffa03ca729>] __set_extent_bit+0x107/0x3f4 [btrfs]
+[ 3915.145120] [<ffffffffa038c1e3>] ? btrfs_kill_super+0x17/0x23 [btrfs]
+[ 3915.146352] [<ffffffff811548f6>] ? deactivate_locked_super+0x3b/0x50
+[ 3915.147565] [<ffffffffa03cb256>] lock_extent_bits+0x65/0x1bf [btrfs]
+[ 3915.148785] [<ffffffff8142b7e2>] ? _raw_write_unlock+0x28/0x33
+[ 3915.149931] [<ffffffffa03bc325>] btrfs_evict_inode+0x196/0x482 [btrfs]
+[ 3915.151154] [<ffffffff81168904>] evict+0xa0/0x148
+[ 3915.152094] [<ffffffff811689e5>] dispose_list+0x39/0x43
+[ 3915.153081] [<ffffffff81169564>] evict_inodes+0xdc/0xeb
+[ 3915.154062] [<ffffffff81154418>] generic_shutdown_super+0x49/0xef
+[ 3915.155193] [<ffffffff811546d1>] kill_anon_super+0x13/0x1e
+[ 3915.156274] [<ffffffffa038c1e3>] btrfs_kill_super+0x17/0x23 [btrfs]
+(...)
+[ 3915.167404] ---[ end trace 14843d3e2e622fc2 ]---
+
+So just bail out of the clone ioctl if the length of the region to clone
+is zero, without locking any extent range, in order to prevent this issue
+(same behaviour as a pwrite with a 0 length for example).
+
+This is trivial to reproduce. For example, the steps for the test I just
+made for fstests:
+
+ mkfs.btrfs -f SCRATCH_DEV
+ mount SCRATCH_DEV $SCRATCH_MNT
+
+ touch $SCRATCH_MNT/foo
+ touch $SCRATCH_MNT/bar
+
+ $CLONER_PROG -s 0 -d 4096 -l 0 $SCRATCH_MNT/foo $SCRATCH_MNT/bar
+ umount $SCRATCH_MNT
+
+A test case for fstests follows soon.
+
+Signed-off-by: Filipe Manana <fdmanana@suse.com>
+Reviewed-by: Omar Sandoval <osandov@osandov.com>
+Signed-off-by: Chris Mason <clm@fb.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/btrfs/ioctl.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+--- a/fs/btrfs/ioctl.c
++++ b/fs/btrfs/ioctl.c
+@@ -3226,6 +3226,11 @@ static noinline long btrfs_ioctl_clone(s
+ if (off + len == src->i_size)
+ len = ALIGN(src->i_size, bs) - off;
+
++ if (len == 0) {
++ ret = 0;
++ goto out_unlock;
++ }
++
+ /* verify the end result is block aligned */
+ if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
+ !IS_ALIGNED(destoff, bs))
--- /dev/null
+From 113e8283869b9855c8b999796aadd506bbac155f Mon Sep 17 00:00:00 2001
+From: Filipe Manana <fdmanana@suse.com>
+Date: Mon, 30 Mar 2015 18:26:47 +0100
+Subject: Btrfs: fix inode eviction infinite loop after extent_same ioctl
+
+From: Filipe Manana <fdmanana@suse.com>
+
+commit 113e8283869b9855c8b999796aadd506bbac155f upstream.
+
+If we pass a length of 0 to the extent_same ioctl, we end up locking an
+extent range with a start offset greater then its end offset (if the
+destination file's offset is greater than zero). This results in a warning
+from extent_io.c:insert_state through the following call chain:
+
+ btrfs_extent_same()
+ btrfs_double_lock()
+ lock_extent_range()
+ lock_extent(inode->io_tree, offset, offset + len - 1)
+ lock_extent_bits()
+ __set_extent_bit()
+ insert_state()
+ --> WARN_ON(end < start)
+
+This leads to an infinite loop when evicting the inode. This is the same
+problem that my previous patch titled
+"Btrfs: fix inode eviction infinite loop after cloning into it" addressed
+but for the extent_same ioctl instead of the clone ioctl.
+
+Signed-off-by: Filipe Manana <fdmanana@suse.com>
+Reviewed-by: Omar Sandoval <osandov@osandov.com>
+Signed-off-by: Chris Mason <clm@fb.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/btrfs/ioctl.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/fs/btrfs/ioctl.c
++++ b/fs/btrfs/ioctl.c
+@@ -2708,6 +2708,9 @@ static int btrfs_extent_same(struct inod
+ if (src == dst)
+ return -EINVAL;
+
++ if (len == 0)
++ return 0;
++
+ btrfs_double_lock(src, loff, dst, dst_loff, len);
+
+ ret = extent_same_check_offsets(src, loff, len);
--- /dev/null
+From dcc82f4783ad91d4ab654f89f37ae9291cdc846a Mon Sep 17 00:00:00 2001
+From: Filipe Manana <fdmanana@suse.com>
+Date: Mon, 23 Mar 2015 14:07:40 +0000
+Subject: Btrfs: fix log tree corruption when fs mounted with -o discard
+
+From: Filipe Manana <fdmanana@suse.com>
+
+commit dcc82f4783ad91d4ab654f89f37ae9291cdc846a upstream.
+
+While committing a transaction we free the log roots before we write the
+new super block. Freeing the log roots implies marking the disk location
+of every node/leaf (metadata extent) as pinned before the new super block
+is written. This is to prevent the disk location of log metadata extents
+from being reused before the new super block is written, otherwise we
+would have a corrupted log tree if before the new super block is written
+a crash/reboot happens and the location of any log tree metadata extent
+ended up being reused and rewritten.
+
+Even though we pinned the log tree's metadata extents, we were issuing a
+discard against them if the fs was mounted with the -o discard option,
+resulting in corruption of the log tree if a crash/reboot happened before
+writing the new super block - the next time the fs was mounted, during
+the log replay process we would find nodes/leafs of the log btree with
+a content full of zeroes, causing the process to fail and require the
+use of the tool btrfs-zero-log to wipeout the log tree (and all data
+previously fsynced becoming lost forever).
+
+Fix this by not doing a discard when pinning an extent. The discard will
+be done later when it's safe (after the new super block is committed) at
+extent-tree.c:btrfs_finish_extent_commit().
+
+Fixes: e688b7252f78 (Btrfs: fix extent pinning bugs in the tree log)
+Signed-off-by: Filipe Manana <fdmanana@suse.com>
+Signed-off-by: Chris Mason <clm@fb.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/btrfs/extent-tree.c | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+--- a/fs/btrfs/extent-tree.c
++++ b/fs/btrfs/extent-tree.c
+@@ -6645,12 +6645,11 @@ static int __btrfs_free_reserved_extent(
+ return -ENOSPC;
+ }
+
+- if (btrfs_test_opt(root, DISCARD))
+- ret = btrfs_discard_extent(root, start, len, NULL);
+-
+ if (pin)
+ pin_down_extent(root, cache, start, len, 1);
+ else {
++ if (btrfs_test_opt(root, DISCARD))
++ ret = btrfs_discard_extent(root, start, len, NULL);
+ btrfs_add_free_space(cache, start, len);
+ btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
+ }
--- /dev/null
+From f8e617f4582995f7c25ef25b4167213120ad122b Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <bitbucket@online.de>
+Date: Sat, 18 Jan 2014 17:14:44 +0100
+Subject: sched/idle/x86: Optimize unnecessary mwait_idle() resched IPIs
+
+From: Mike Galbraith <bitbucket@online.de>
+
+commit f8e617f4582995f7c25ef25b4167213120ad122b upstream.
+
+To fully take advantage of MWAIT, apparently the CLFLUSH instruction needs
+another quirk on certain CPUs: proper barriers around it on certain machines.
+
+On a Q6600 SMP system, pipe-test scheduling performance, cross core,
+improves significantly:
+
+ 3.8.13 487.2 KHz 1.000
+ 3.13.0-master 415.5 KHz .852
+ 3.13.0-master+ 415.2 KHz .852 + restore mwait_idle
+ 3.13.0-master++ 488.5 KHz 1.002 + restore mwait_idle + IPI fix
+
+Since X86_BUG_CLFLUSH_MONITOR is already a quirk, don't create a separate
+quirk for the extra smp_mb()s.
+
+Signed-off-by: Mike Galbraith <bitbucket@online.de>
+Cc: Borislav Petkov <bp@alien8.de>
+Cc: H. Peter Anvin <hpa@zytor.com>
+Cc: Ian Malone <ibmalone@gmail.com>
+Cc: Josh Boyer <jwboyer@redhat.com>
+Cc: Len Brown <len.brown@intel.com>
+Cc: Len Brown <lenb@kernel.org>
+Cc: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: Mike Galbraith <efault@gmx.de>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Thomas Gleixner <tglx@linutronix.de>
+Link: http://lkml.kernel.org/r/1390061684.5566.4.camel@marge.simpson.net
+[ Ported to recent kernel, added comments about the quirk. ]
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/x86/kernel/process.c | 12 ++++++++----
+ 1 file changed, 8 insertions(+), 4 deletions(-)
+
+--- a/arch/x86/kernel/process.c
++++ b/arch/x86/kernel/process.c
+@@ -428,18 +428,22 @@ static int prefer_mwait_c1_over_halt(con
+
+ static void mwait_idle(void)
+ {
+- if (!need_resched()) {
+- if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR))
++ if (!current_set_polling_and_test()) {
++ if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) {
++ smp_mb(); /* quirk */
+ clflush((void *)¤t_thread_info()->flags);
++ smp_mb(); /* quirk */
++ }
+
+ __monitor((void *)¤t_thread_info()->flags, 0, 0);
+- smp_mb();
+ if (!need_resched())
+ __sti_mwait(0, 0);
+ else
+ local_irq_enable();
+- } else
++ } else {
+ local_irq_enable();
++ }
++ __current_clr_polling();
+ }
+
+ void select_idle_routine(const struct cpuinfo_x86 *c)
--- /dev/null
+From b253149b843f89cd300cbdbea27ce1f847506f99 Mon Sep 17 00:00:00 2001
+From: Len Brown <len.brown@intel.com>
+Date: Wed, 15 Jan 2014 00:37:34 -0500
+Subject: sched/idle/x86: Restore mwait_idle() to fix boot hangs, to improve power savings and to improve performance
+
+From: Len Brown <len.brown@intel.com>
+
+commit b253149b843f89cd300cbdbea27ce1f847506f99 upstream.
+
+In Linux-3.9 we removed the mwait_idle() loop:
+
+ 69fb3676df33 ("x86 idle: remove mwait_idle() and "idle=mwait" cmdline param")
+
+The reasoning was that modern machines should be sufficiently
+happy during the boot process using the default_idle() HALT
+loop, until cpuidle loads and either acpi_idle or intel_idle
+invoke the newer MWAIT-with-hints idle loop.
+
+But two machines reported problems:
+
+ 1. Certain Core2-era machines support MWAIT-C1 and HALT only.
+ MWAIT-C1 is preferred for optimal power and performance.
+ But if they support just C1, cpuidle never loads and
+ so they use the boot-time default idle loop forever.
+
+ 2. Some laptops will boot-hang if HALT is used,
+ but will boot successfully if MWAIT is used.
+ This appears to be a hidden assumption in BIOS SMI,
+ that is presumably valid on the proprietary OS
+ where the BIOS was validated.
+
+ https://bugzilla.kernel.org/show_bug.cgi?id=60770
+
+So here we effectively revert the patch above, restoring
+the mwait_idle() loop. However, we don't bother restoring
+the idle=mwait cmdline parameter, since it appears to add
+no value.
+
+Maintainer notes:
+
+ For 3.9, simply revert 69fb3676df
+ for 3.10, patch -F3 applies, fuzz needed due to __cpuinit use in
+ context For 3.11, 3.12, 3.13, this patch applies cleanly
+
+Tested-by: Mike Galbraith <bitbucket@online.de>
+Signed-off-by: Len Brown <len.brown@intel.com>
+Acked-by: Mike Galbraith <bitbucket@online.de>
+Cc: Borislav Petkov <bp@alien8.de>
+Cc: H. Peter Anvin <hpa@zytor.com>
+Cc: Ian Malone <ibmalone@gmail.com>
+Cc: Josh Boyer <jwboyer@redhat.com>
+Cc: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: Mike Galbraith <efault@gmx.de>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Thomas Gleixner <tglx@linutronix.de>
+Link: http://lkml.kernel.org/r/345254a551eb5a6a866e048d7ab570fd2193aca4.1389763084.git.len.brown@intel.com
+[ Ported to recent kernels. ]
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/x86/include/asm/mwait.h | 8 +++++++
+ arch/x86/kernel/process.c | 47 +++++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 55 insertions(+)
+
+--- a/arch/x86/include/asm/mwait.h
++++ b/arch/x86/include/asm/mwait.h
+@@ -30,6 +30,14 @@ static inline void __mwait(unsigned long
+ :: "a" (eax), "c" (ecx));
+ }
+
++static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
++{
++ trace_hardirqs_on();
++ /* "mwait %eax, %ecx;" */
++ asm volatile("sti; .byte 0x0f, 0x01, 0xc9;"
++ :: "a" (eax), "c" (ecx));
++}
++
+ /*
+ * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
+ * which can obviate IPI to trigger checking of need_resched.
+--- a/arch/x86/kernel/process.c
++++ b/arch/x86/kernel/process.c
+@@ -24,6 +24,7 @@
+ #include <asm/syscalls.h>
+ #include <asm/idle.h>
+ #include <asm/uaccess.h>
++#include <asm/mwait.h>
+ #include <asm/i387.h>
+ #include <asm/fpu-internal.h>
+ #include <asm/debugreg.h>
+@@ -398,6 +399,49 @@ static void amd_e400_idle(void)
+ default_idle();
+ }
+
++/*
++ * Intel Core2 and older machines prefer MWAIT over HALT for C1.
++ * We can't rely on cpuidle installing MWAIT, because it will not load
++ * on systems that support only C1 -- so the boot default must be MWAIT.
++ *
++ * Some AMD machines are the opposite, they depend on using HALT.
++ *
++ * So for default C1, which is used during boot until cpuidle loads,
++ * use MWAIT-C1 on Intel HW that has it, else use HALT.
++ */
++static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
++{
++ if (c->x86_vendor != X86_VENDOR_INTEL)
++ return 0;
++
++ if (!cpu_has(c, X86_FEATURE_MWAIT))
++ return 0;
++
++ return 1;
++}
++
++/*
++ * MONITOR/MWAIT with no hints, used for default default C1 state.
++ * This invokes MWAIT with interrutps enabled and no flags,
++ * which is backwards compatible with the original MWAIT implementation.
++ */
++
++static void mwait_idle(void)
++{
++ if (!need_resched()) {
++ if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR))
++ clflush((void *)¤t_thread_info()->flags);
++
++ __monitor((void *)¤t_thread_info()->flags, 0, 0);
++ smp_mb();
++ if (!need_resched())
++ __sti_mwait(0, 0);
++ else
++ local_irq_enable();
++ } else
++ local_irq_enable();
++}
++
+ void select_idle_routine(const struct cpuinfo_x86 *c)
+ {
+ #ifdef CONFIG_SMP
+@@ -411,6 +455,9 @@ void select_idle_routine(const struct cp
+ /* E400: APIC timer interrupt does not wake up CPU from C1e */
+ pr_info("using AMD E400 aware idle routine\n");
+ x86_idle = amd_e400_idle;
++ } else if (prefer_mwait_c1_over_halt(c)) {
++ pr_info("using mwait in idle threads\n");
++ x86_idle = mwait_idle;
+ } else
+ x86_idle = default_idle;
+ }
tcp-avoid-looping-in-tcp_send_fin.patch
net-do-not-deplete-pfmemalloc-reserve.patch
net-fix-crash-in-build_skb.patch
+sched-idle-x86-restore-mwait_idle-to-fix-boot-hangs-to-improve-power-savings-and-to-improve-performance.patch
+sched-idle-x86-optimize-unnecessary-mwait_idle-resched-ipis.patch
+btrfs-fix-log-tree-corruption-when-fs-mounted-with-o-discard.patch
+btrfs-don-t-accept-bare-namespace-as-a-valid-xattr.patch
+btrfs-fix-inode-eviction-infinite-loop-after-cloning-into-it.patch
+btrfs-fix-inode-eviction-infinite-loop-after-extent_same-ioctl.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
