Lockdep issues a circular dependency warning when AFS issues an operation
through AF_RXRPC from a context in which the VFS/VM holds the mmap_sem.
The theory lockdep comes up with is as follows:
(1) If the pagefault handler decides it needs to read pages from AFS, it
calls AFS with mmap_sem held and AFS begins an AF_RXRPC call, but
creating a call requires the socket lock:
mmap_sem must be taken before sk_lock-AF_RXRPC
(2) afs_open_socket() opens an AF_RXRPC socket and binds it. rxrpc_bind()
binds the underlying UDP socket whilst holding its socket lock.
inet_bind() takes its own socket lock:
sk_lock-AF_RXRPC must be taken before sk_lock-AF_INET
(3) Reading from a TCP socket into a userspace buffer might cause a fault
and thus cause the kernel to take the mmap_sem, but the TCP socket is
locked whilst doing this:
sk_lock-AF_INET must be taken before mmap_sem
However, lockdep's theory is wrong in this instance because it deals only
with lock classes and not individual locks. The AF_INET lock in (2) isn't
really equivalent to the AF_INET lock in (3) as the former deals with a
socket entirely internal to the kernel that never sees userspace. This is
a limitation in the design of lockdep.
Fix the general case by:
(1) Double up all the locking keys used in sockets so that one set are
used if the socket is created by userspace and the other set is used
if the socket is created by the kernel.
(2) Store the kern parameter passed to sk_alloc() in a variable in the
sock struct (sk_kern_sock). This informs sock_lock_init(),
sock_init_data() and sk_clone_lock() as to the lock keys to be used.
Note that the child created by sk_clone_lock() inherits the parent's
kern setting.
(3) Add a 'kern' parameter to ->accept() that is analogous to the one
passed in to ->create() that distinguishes whether kernel_accept() or
sys_accept4() was the caller and can be passed to sk_alloc().
Note that a lot of accept functions merely dequeue an already
allocated socket. I haven't touched these as the new socket already
exists before we get the parameter.
Note also that there are a couple of places where I've made the accepted
socket unconditionally kernel-based:
irda_accept()
rds_rcp_accept_one()
tcp_accept_from_sock()
because they follow a sock_create_kern() and accept off of that.
Whilst creating this, I noticed that lustre and ocfs don't create sockets
through sock_create_kern() and thus they aren't marked as for-kernel,
though they appear to be internal. I wonder if these should do that so
that they use the new set of lock keys.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
No point in going through loops and hoops instead of just comparing the
values.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull dlm fixes from David Teigland:
"This set fixes error reporting for dlm sockets, removes the unbound
property on the dlm callback workqueue to improve performance, and
includes a couple trivial changes"
* tag 'dlm-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
dlm: fix error return code in sctp_accept_from_sock()
dlm: don't specify WQ_UNBOUND for the ast callback workqueue
dlm: remove lock_sock to avoid scheduling while atomic
dlm: don't save callbacks after accept
dlm: audit and remove any unnecessary uses of module.h
dlm: make genl_ops const
Now genl_register_family() is the only thing (other than the
users themselves, perhaps, but I didn't find any doing that)
writing to the family struct.
In all families that I found, genl_register_family() is only
called from __init functions (some indirectly, in which case
I've add __init annotations to clarifly things), so all can
actually be marked __ro_after_init.
This protects the data structure from accidental corruption.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of providing macros/inline functions to initialize
the families, make all users initialize them statically and
get rid of the macros.
This reduces the kernel code size by about 1.6k on x86-64
(with allyesconfig).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Static family IDs have never really been used, the only
use case was the workaround I introduced for those users
that assumed their family ID was also their multicast
group ID.
Additionally, because static family IDs would never be
reserved by the generic netlink code, using a relatively
low ID would only work for built-in families that can be
registered immediately after generic netlink is started,
which is basically only the control family (apart from
the workaround code, which I also had to add code for so
it would reserve those IDs)
Thus, anything other than GENL_ID_GENERATE is flawed and
luckily not used except in the cases I mentioned. Move
those workarounds into a few lines of code, and then get
rid of GENL_ID_GENERATE entirely, making it more robust.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes the WQ_UNBOUND flag (which implies WQ_HIGHPRI)
from the DLM's ast work queue, in favor of just WQ_HIGHPRI.
This has been shown to cause a 19 percent performance increase for
simultaneous inode creates on GFS2 with fs_mark.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Before this patch, functions save_callbacks and restore_callbacks
called function lock_sock and release_sock to prevent other processes
from messing with the struct sock while the callbacks were saved and
restored. However, function add_sock calls write_lock_bh prior to
calling it save_callbacks, which disables preempts. So the call to
lock_sock would try to schedule when we can't schedule.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
When DLM calls accept() on a socket, the comm code copies the sk
after we've saved its callbacks. Afterward, it calls add_sock which
saves the callbacks a second time. Since the error reporting function
lowcomms_error_report calls the previous callback too, this results
in a recursive call to itself. This patch adds a new parameter to
function add_sock to tell whether to save the callbacks. Function
tcp_accept_from_sock (and its sctp counterpart) then calls it with
false to avoid the recursion.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends. That changed
when we forked out support for the latter into the export.h file.
This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.
In the case of some code where it is modular, we can extend that to
also include files that are building basic support functionality but
not related to loading or registering the final module; such files
also have no need whatsoever for module.h
The advantage in removing such instances is that module.h itself
sources about 15 other headers; adding significantly to what we feed
cpp, and it can obscure what headers we are effectively using.
Since module.h might have been the implicit source for init.h
(for __init) and for export.h (for EXPORT_SYMBOL) we consider each
instance for the presence of either and replace as needed.
In the dlm case, we remove module.h from a global header and only
introduce it in the files where it is explicitly required, since
there is nothing modular in dlm_internal.h itself.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David Teigland <teigland@redhat.com>
After backporting commit ee44b4bc05 ("dlm: use sctp 1-to-1 API")
series to a kernel with an older workqueue which didn't use RCU yet, it
was noticed that we are freeing the workqueues in dlm_lowcomms_stop()
too early as free_conn() will try to access that memory for canceling
the queued works if any.
This issue was introduced by commit 0d737a8cfd as before it such
attempt to cancel the queued works wasn't performed, so the issue was
not present.
This patch fixes it by simply inverting the free order.
Cc: stable@vger.kernel.org
Fixes: 0d737a8cfd ("dlm: fix race while closing connections")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David Teigland <teigland@redhat.com>
With the current kernel, `dlm_tool lockdebug` fails as below:
"dlm_tool lockdebug ED0BD86DCE724393918A1AE8FDBF1EE3
can't open /sys/kernel/debug/dlm/ED0BD86DCE724393918A1AE8FDBF1EE3:
Operation not permitted"
This is because table_open() depends on file->f_op to tell which
seq_file ops should be passed down. But, the original file ops in
file->f_op is replaced by "debugfs_full_proxy_file_operations" with
commit 49d200deaa ("debugfs: prevent access to removed files'
private data").
Currently, I can think up 2 solutions: 1st, replace
debugfs_create_file() with debugfs_create_file_unsafe();
2nd, make different table_open#() accordingly. The 1st one
is neat, but I don't thoroughly understand its risk. Maybe
someone has a better one.
Signed-off-by: Eric Ren <zren@suse.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Replace calls to kmalloc followed by a memcpy with a direct call to
kmemdup.
The Coccinelle semantic patch used to make this change is as follows:
@@
expression from,to,size,flag;
statement S;
@@
- to = \(kmalloc\|kzalloc\)(size,flag);
+ to = kmemdup(from,size,flag);
if (to==NULL || ...) S
- memcpy(to, from, size);
Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This config option can be used to disable the
LOG_INFO recovery messages.
Signed-off-by: Zhilong Liu <zlliu@suse.com>
Signed-off-by: David Teigland <teigland@redhat.com>
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.
This promise never materialized. And unlikely will.
We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.
Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.
Let's stop pretending that pages in page cache are special. They are
not.
The changes are pretty straight-forward:
- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
- page_cache_get() -> get_page();
- page_cache_release() -> put_page();
This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.
The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.
There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.
virtual patch
@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT
@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE
@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK
@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)
@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)
@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 1ae1602de0 "configfs: switch ->default groups to a linked list"
left the NULL gps pointer behind after removing the kcalloc() call which
made it non-NULL. It also left the !gps check in place so make_cluster()
now fails with ENOMEM. Remove the remaining uses of the gps variable to
fix that.
Reviewed-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Pull dlm updates from David Teigland:
"Previous changes introduced the use of socket error reporting for dlm
sockets. This set includes two fixes in how the socket error
callbacks are used"
* tag 'dlm-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
DLM: Save and restore socket callbacks properly
DLM: Replace nodeid_to_addr with kernel_getpeername
Replace the current NULL-terminated array of default groups with a linked
list. This gets rid of lots of nasty code to size and/or dynamically
allocate the array.
While we're at it also provide a conveniant helper to remove the default
groups.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Felipe Balbi <balbi@kernel.org> [drivers/usb/gadget]
Acked-by: Joel Becker <jlbec@evilplan.org>
Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
This patch fixes the problems with patch b3a5bbfd7.
1. It removes a return statement from lowcomms_error_report
because it needs to call the original error report in all paths
through the function.
2. All socket callbacks are saved and restored, not just the
sk_error_report, and that's done so with proper locking like
sunrpc does.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch replaces the call to nodeid_to_addr with a call to
kernel_getpeername. This avoids taking a spinlock because it may
potentially be called from a softirq context.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
David Howells
Ingo Molnar
Thomas Gleixner
Linus Torvalds
Johannes Berg
Wei Yongjun
Bob Peterson
Paul Gortmaker
Stephen Hemminger
Marcelo Ricardo Leitner
Eric Ren
Amitoj Kaur Chawla
Zhilong Liu
Kirill A. Shutemov
Andrew Price
Christoph Hellwig