Al Viro [Fri, 8 May 2015 21:37:07 +0000 (17:37 -0400)]
namei: lift link_path_walk() call out of trailing_symlink()
Make trailing_symlink() return the pathname to traverse or ERR_PTR(-E...).
A subtle point is that for "magic" symlinks it returns "" now - that
leads to link_path_walk("", nd), which is immediately returning 0 and
we are back to the treatment of the last component, at whereever the
damn thing has left us.
Reduces the stack footprint - link_path_walk() called on more shallow
stack now.
Al Viro [Fri, 8 May 2015 21:19:59 +0000 (17:19 -0400)]
namei: path_init() calling conventions change
* lift link_path_walk() into callers; moving it down into path_init()
had been a mistake. Stack footprint, among other things...
* do _not_ call path_cleanup() after path_init() failure; on all failure
exits out of it we have nothing for path_cleanup() to do
* have path_init() return pathname or ERR_PTR(-E...)
Al Viro [Sun, 10 May 2015 15:50:01 +0000 (11:50 -0400)]
namei: take increment of nd->depth into pick_link()
Makes the situation much more regular - we avoid a strange state
when the element just after the top of stack is used to store
struct path of symlink, but isn't counted in nd->depth. This
is much more regular, so the normal failure exits, etc., work
fine.
Al Viro [Fri, 8 May 2015 20:28:42 +0000 (16:28 -0400)]
namei: fold put_link() into the failure case of complete_walk()
... and don't open-code unlazy_walk() in there - the only reason
for that is to avoid verfication of cached nd->root, which is
trivially avoided by discarding said cached nd->root first.
Al Viro [Sun, 10 May 2015 15:01:00 +0000 (11:01 -0400)]
namei: take the treatment of absolute symlinks to get_link()
rather than letting the callers handle the jump-to-root part of
semantics, do it right in get_link() and return the rest of the
body for the caller to deal with - at that point it's treated
the same way as relative symlinks would be. And return NULL
when there's no "rest of the body" - those are treated the same
as pure jump symlink would be.
Al Viro [Sun, 10 May 2015 14:50:41 +0000 (10:50 -0400)]
namei: simpler treatment of symlinks with nothing other that / in the body
Instead of saving name and branching to OK:, where we'll immediately restore
it, and call walk_component() with WALK_PUT|WALK_GET and nd->last_type being
LAST_BIND, which is equivalent to put_link(nd), err = 0, we can just treat
that the same way we'd treat procfs-style "jump" symlinks - do put_link(nd)
and move on.
Al Viro [Sun, 10 May 2015 14:43:46 +0000 (10:43 -0400)]
namei: simplify failure exits in get_link()
when cookie is NULL, put_link() is equivalent to path_put(), so
as soon as we'd set last->cookie to NULL, we can bump nd->depth and
let the normal logics in terminate_walk() to take care of cleanups.
Al Viro [Wed, 22 Apr 2015 14:30:08 +0000 (10:30 -0400)]
namei: simplify the callers of follow_managed()
now that it gets nameidata, no reason to have setting LOOKUP_JUMPED on
mountpoint crossing and calling path_put_conditional() on failures
done in every caller.
NeilBrown [Mon, 23 Mar 2015 02:37:38 +0000 (13:37 +1100)]
VFS: replace {, total_}link_count in task_struct with pointer to nameidata
task_struct currently contains two ad-hoc members for use by the VFS:
link_count and total_link_count. These are only interesting to fs/namei.c,
so exposing them explicitly is poor layering. Incidentally, link_count
isn't used anymore, so it can just die.
This patches replaces those with a single pointer to 'struct nameidata'.
This structure represents the current filename lookup of which
there can only be one per process, and is a natural place to
store total_link_count.
This will allow the current "nameidata" argument to all
follow_link operations to be removed as current->nameidata
can be used instead in the _very_ few instances that care about
it at all.
As there are occasional circumstances where pathname lookup can
recurse, such as through kern_path_locked, we always save and old
current->nameidata (if there is one) when setting a new value, and
make sure any active link_counts are preserved.
follow_mount and follow_automount now get a 'struct nameidata *'
rather than 'int flags' so that they can directly access
total_link_count, rather than going through 'current'.
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro [Mon, 4 May 2015 21:47:11 +0000 (17:47 -0400)]
namei: new calling conventions for walk_component()
instead of a single flag (!= 0 => we want to follow symlinks) pass
two bits - WALK_GET (want to follow symlinks) and WALK_PUT (put_link()
once we are done looking at the name). The latter matters only for
success exits - on failure the caller will discard everything anyway.
Suggestions for better variant are welcome; what this thing aims for
is making sure that pending put_link() is done *before* walk_component()
decides to pick a symlink up, rather than between picking it up and
acting upon it. See the next commit for payoff.
Al Viro [Mon, 4 May 2015 12:34:59 +0000 (08:34 -0400)]
namei: have terminate_walk() do put_link() on everything left
All callers of terminate_walk() are followed by more or less
open-coded eqiuvalent of "do put_link() on everything left
in nd->stack". Better done in terminate_walk() itself, and
when we go for RCU symlink traversal we'll have to do it
there anyway.
Al Viro [Mon, 4 May 2015 12:26:45 +0000 (08:26 -0400)]
namei: take put_link() into {lookup,mountpoint,do}_last()
rationale: we'll need to have terminate_walk() do put_link() on
everything, which will mean that in some cases ..._last() will do
put_link() anyway. Easier to have them do it in all cases.
Al Viro [Mon, 4 May 2015 11:53:00 +0000 (07:53 -0400)]
namei: lift (open-coded) terminate_walk() in follow_dotdot_rcu() into callers
follow_dotdot_rcu() does an equivalent of terminate_walk() on failure;
shifting it into callers makes for simpler rules and those callers
already have terminate_walk() on other failure exits.
Al Viro [Mon, 4 May 2015 01:30:27 +0000 (21:30 -0400)]
namei: we never need more than MAXSYMLINKS entries in nd->stack
The only reason why we needed one more was that purely nested
MAXSYMLINKS symlinks could lead to path_init() using that many
entries in addition to nd->stack[0] which it left unused.
That can't happen now - path_init() starts with entry 0 (and
trailing_symlink() is called only when we'd already encountered
one symlink, so no more than MAXSYMLINKS-1 are left).
Al Viro [Mon, 4 May 2015 01:27:36 +0000 (21:27 -0400)]
link_path_walk: end of nd->depth massage
get rid of orig_depth - we only use it on error exit to tell whether
to stop doing put_link() when depth reaches 0 (call from path_init())
or when it reaches 1 (call from trailing_symlink()). However, in
the latter case the caller would immediately follow with one more
put_link(). Just keep doing it until the depth reaches zero (and
simplify trailing_symlink() as the result).
Al Viro [Mon, 4 May 2015 01:21:44 +0000 (21:21 -0400)]
link_path_walk: nd->depth massage, part 10
Get rid of orig_depth checks in OK: logics. If nd->depth is
zero, we had been called from path_init() and we are done.
If it is greater than 1, we are not done, whether we'd been
called from path_init() or trailing_symlink(). And in
case when it's 1, we might have been called from path_init()
and reached the end of nested symlink (in which case
nd->stack[0].name will point to the rest of pathname and
we are not done) or from trailing_symlink(), in which case
we are done.
Just have trailing_symlink() leave NULL in nd->stack[0].name
and use that to discriminate between those cases.
Al Viro [Mon, 4 May 2015 01:16:35 +0000 (21:16 -0400)]
link_path_walk: nd->depth massage, part 9
Make link_path_walk() work with any value of nd->depth on entry -
memorize it and use it in tests instead of comparing with 1.
Don't bother with increment/decrement in path_init().
Al Viro [Mon, 4 May 2015 00:01:27 +0000 (20:01 -0400)]
link_path_walk: nd->depth massage, part 1
nd->stack[0] is unused until the handling of trailing symlinks and
we want to get rid of that. Having fucked that transformation up
several times, I went for bloody pedantic series of provably equivalent
transformations. Sorry.
Step 1: keep nd->depth higher by one in link_path_walk() - increment upon
entry, decrement on exits, adjust the arithmetics inside and surround the
calls of functions that care about nd->depth value (nd_alloc_stack(),
get_link(), put_link()) with decrement/increment pairs.
Al Viro [Sat, 2 May 2015 23:38:35 +0000 (19:38 -0400)]
namei: move link/cookie pairs into nameidata
Array of MAX_NESTED_LINKS + 1 elements put into nameidata;
what used to be a local array in link_path_walk() occupies
entries 1 .. MAX_NESTED_LINKS in it, link and cookie from
the trailing symlink handling loops - entry 0.
This is _not_ the final arrangement; just an easily verified
incremental step.
Al Viro [Sun, 19 Apr 2015 00:30:49 +0000 (20:30 -0400)]
link_path_walk: kill the recursion
absolutely straightforward now - the only variables we need to preserve
across the recursive call are name, link and cookie, and recursion depth
is limited (and can is equal to nd->depth). So arrange an array of
triples to hold instances of those and be done with that.
Al Viro [Sun, 19 Apr 2015 00:21:40 +0000 (20:21 -0400)]
link_path_walk: final preparations to killing recursion
reduce the number of returns in there - turn all places
where it returns zero into goto OK and places where it
returns non-zero into goto Err. The only non-trivial
detail is that all breaks in the loop are guaranteed
to be with non-zero err.
Al Viro [Sun, 19 Apr 2015 00:14:20 +0000 (20:14 -0400)]
link_path_walk: get rid of duplication
What we do after the second walk_component() + put_link() + depth
decrement in there is exactly equivalent to what's done right
after the first walk_component(). Easy to verify and not at all
surprising, seeing that there we have just walked the last
component of nested symlink.
If we get ERR_PTR() from get_link(), we are guaranteed to get err != 0
when we break out of do-while, so we are going to hit if (err) return err;
shortly after it. Pull that into the if (IS_ERR(s)) body.
Al Viro [Sat, 18 Apr 2015 22:23:41 +0000 (18:23 -0400)]
namei.c: separate the parts of follow_link() that find the link body
Split a piece of fs/namei.c:follow_link() that does obtaining the link
body into a separate function. follow_link() itself is converted to
calling get_link() and then doing the body traversal (if any).
The next step will expand follow_link() call in link_path_walk()
and this helps to keep the size down...
Al Viro [Sat, 2 May 2015 17:32:22 +0000 (13:32 -0400)]
new ->follow_link() and ->put_link() calling conventions
a) instead of storing the symlink body (via nd_set_link()) and returning
an opaque pointer later passed to ->put_link(), ->follow_link() _stores_
that opaque pointer (into void * passed by address by caller) and returns
the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic
symlinks) and pointer to symlink body for normal symlinks. Stored pointer
is ignored in all cases except the last one.
Storing NULL for opaque pointer (or not storing it at all) means no call
of ->put_link().
b) the body used to be passed to ->put_link() implicitly (via nameidata).
Now only the opaque pointer is. In the cases when we used the symlink body
to free stuff, ->follow_link() now should store it as opaque pointer in addition
to returning it.
NeilBrown [Mon, 23 Mar 2015 02:37:39 +0000 (13:37 +1100)]
SECURITY: remove nameidata arg from inode_follow_link.
No ->inode_follow_link() methods use the nameidata arg, and
it is about to become private to namei.c.
So remove from all inode_follow_link() functions.
Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
NeilBrown [Mon, 23 Mar 2015 02:37:39 +0000 (13:37 +1100)]
ovl: rearrange ovl_follow_link to it doesn't need to call ->put_link
ovl_follow_link current calls ->put_link on an error path.
However ->put_link is about to change in a way that it will be
impossible to call it from ovl_follow_link.
So rearrange the code to avoid the need for that error path.
Specifically: move the kmalloc() call before the ->follow_link()
call to the subordinate filesystem.
Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro [Tue, 14 Apr 2015 21:42:49 +0000 (17:42 -0400)]
9p: don't bother with __getname() in ->follow_link()
We copy there a kmalloc'ed string and proceed to kfree that string immediately
after that. Easier to just feed that string to nd_set_link() and _not_
kfree it until ->put_link() (which becomes kfree_put_link() in that case).
Linus Torvalds [Sun, 10 May 2015 21:58:53 +0000 (14:58 -0700)]
Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux
Pull drm fixes from Dave Airlie:
"I really need to get back to sending these on my Friday, instead of my
Monday morning, but nothing too amazing in here: a few amdkfd fixes, a
few radeon fixes, i915 fixes, one tegra fix and one core fix"
* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
drm: Zero out invalid vblank timestamp in drm_update_vblank_count.
drm/tegra: Don't use vblank_disable_immediate on incapable driver.
drm/radeon: stop trying to suspend UVD sessions
drm/radeon: more strictly validate the UVD codec
drm/radeon: make UVD handle checking more strict
drm/radeon: make VCE handle check more strict
drm/radeon: fix userptr lockup
drm/radeon: fix userptr BO unpin bug v3
drm/amdkfd: Initialize sdma vm when creating sdma queue
drm/amdkfd: Don't report local memory size
drm/amdkfd: allow unregister process with queues
drm/i915: Drop PIPE-A quirk for 945GSE HP Mini
drm/i915: Sink rate read should be saved in deca-kHz
drm/i915/dp: there is no audio on port A
drm/i915: Add missing MacBook Pro models with dual channel LVDS
drm/i915: Assume dual channel LVDS if pixel clock necessitates it
drm/radeon: don't setup audio on asics that don't support it
drm/radeon: disable semaphores for UVD V1 (v2)
Dave Airlie [Sun, 10 May 2015 20:06:22 +0000 (06:06 +1000)]
Merge tag 'drm-intel-fixes-2015-05-08' of git://anongit.freedesktop.org/drm-intel into drm-fixes
misc i915 fixes.
* tag 'drm-intel-fixes-2015-05-08' of git://anongit.freedesktop.org/drm-intel:
drm/i915: Drop PIPE-A quirk for 945GSE HP Mini
drm/i915: Sink rate read should be saved in deca-kHz
drm/i915/dp: there is no audio on port A
drm/i915: Add missing MacBook Pro models with dual channel LVDS
drm/i915: Assume dual channel LVDS if pixel clock necessitates it
Mario Kleiner [Tue, 7 Apr 2015 04:31:09 +0000 (06:31 +0200)]
drm: Zero out invalid vblank timestamp in drm_update_vblank_count.
Since commit 844b03f27739135fe1fed2fef06da0ffc4c7a081 we make
sure that after vblank irq off, we return the last valid
(vblank count, vblank timestamp) pair to clients, e.g., during
modesets, which is good.
An overlooked side effect of that commit for kms drivers without
support for precise vblank timestamping is that at vblank irq
enable, when we update the vblank counter from the hw counter, we
can't update the corresponding vblank timestamp, so now we have a
totally mismatched timestamp for the new count to confuse clients.
Restore old client visible behaviour from before Linux 3.17, but
zero out the timestamp at vblank counter update (instead of disable
as in original implementation) if we can't generate a meaningful
timestamp immediately for the new vblank counter. This will fix
this regression, so callers know they need to retry again later
if they need a valid timestamp, but at the same time preserves
the improvements made in the commit mentioned above.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com> Cc: <stable@vger.kernel.org> #v3.17+ Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>
Linus Torvalds [Sun, 10 May 2015 18:13:19 +0000 (11:13 -0700)]
Merge tag 'samsung-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung
Pull samsung fixes from Kukjin Kim:
"Here is Samsung fixes for v4.1. Since I've missed to send this via
arm-soc tree before v4.1-rc3, so I'm sending this to you directly
- fix commit ea08de16eb1b ("ARM: dts: Add DISP1 power domain for
exynos5420") which causes 'unhandled fault: imprecise external
abort' error when PD turned off. ("make DP a consumer of DISP1
power domain")
- fix 's3c-rtc' probe failure on Odriod-X2/U2/U3 boards ("add
'rtc_src' clock to rtc node for source clock of rtc")
- fix typo for 'cpu-crit-0' trip point on exynos5420/5440
- fix S2R failure on exynos5250-snow due to card power of Marvell
WiFi driver (suspend/resume) ("add keep-power-in-susped to WiFi
SDIO node")"
* tag 'samsung-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung:
ARM: dts: Add keep-power-in-suspend to WiFi SDIO node for exynos5250-snow
ARM: dts: Fix typo in trip point temperature for exynos5420/5440
ARM: dts: add 'rtc_src' clock to rtc node for exynos4412-odroid boards
ARM: dts: Make DP a consumer of DISP1 power domain on Exynos5420
Linus Torvalds [Sat, 9 May 2015 23:13:38 +0000 (16:13 -0700)]
Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC fixes from Arnd Bergmann:
"A few patches have come up since the merge window. The largest one is
a rewrite of the PXA lubbock/mainstone IRQ handling. This was already
broken in 2011 by a change to the GPIO code and only noticed now.
The other changes contained here are:
MAINTAINERS file updates:
- Ray Jui and Scott Branden are now co-maintainers for some of the
mach-bcm chips, while Christian Daudt and Marc Carino have stepped
down.
- Andrew Victor is no longer maintaining at91. Instead, Alexandre
Belloni now becomes an official maintainer, after having done a
bulk of the work for a while.
- Baruch Siach, who added the mach-digicolor platform in 4.1 is now
listed as maintainer
- The git URL for mach-socfpga has changed
Bug fixes:
- Three bug fixes for new rockchip rk3288 code
- A regression fix to make SD card support work on certain ux500
boards
- multiple smaller dts fixes for imx, omap, mvebu, and shmobile
- a regression fiix for omap3 power consumption
- a fix for regression in the ARM CCI bus driver
Configuration changes:
- more imx platforms are now enabled in multi_v7_defconfig"
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (39 commits)
MAINTAINERS: add Conexant Digicolor machines entry
MAINTAINERS: socfpga: update the git repo for SoCFPGA
ARM: multi_v7_defconfig: Select more FSL SoCs
MAINTAINERS: replace an AT91 maintainer
drivers: CCI: fix used_mask init in validate_group()
bus: omap_l3_noc: Fix master id address decoding for OMAP5
bus: omap_l3_noc: Fix offset for DRA7 CLK1_HOST_CLK1_2 instance
ARM: dts: dra7: Fix efuse register size for ABB
ARM: dts: am57xx-beagle-x15: Switch GPIO fan number
ARM: dts: am57xx-beagle-x15: Switch UART mux pins
ARM: dts: am437x-sk: reduce col-scan-delay-us
ARM: dts: am437x-sk: fix for new newhaven display module revision
ARM: dts: am57xx-beagle-x15: Fix RTC aliases
ARM: dts: am57xx-beagle-x15: Fix IRQ type for mcp7941x
ARM: dts: omap3: Add #iommu-cells to isp and iva iommu
ARM: omap2plus_defconfig: Enable EXTCON_USB_GPIO
ARM: dts: OMAP3-N900: Add microphone bias voltages
ARM: OMAP2+: Fix omap off idle power consumption creeping up
MAINTAINERS: Update brcmstb entry
MAINTAINERS: Remove Christian Daudt for mach-bcm
...
Linus Torvalds [Sat, 9 May 2015 23:07:14 +0000 (16:07 -0700)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull user-namespace fix from Eric Biederman:
"Eric Windish recently reported a really bug that allows mounting fresh
copies of proc and sysfs when it really should not be allowed. The
code attempted to verify that proc and sysfs were fully visible but
there is a test missing to ensure that the root of the filesystem is
visible. Doh!
The following patch fixes that.
This fixes a containment issue that the docker folks are seeing"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
mnt: Fix fs_fully_visible to verify the root directory is visible
projects / linux-beck.git / log