In check_unmap() it is possible to get into a dead-locked state if
dma_mapping_error is called.  The problem is that the bucket is locked in
check_unmap, and locked again by debug_dma_mapping_error which is called
by dma_mapping_error.  To resolve that we must release the lock on the
bucket before making the call to dma_mapping_error.

[akpm@linux-foundation.org: restore 80-col trickery to be consistent with the rest of the file]
Signed-off-by: NAlexander Duyck <alexander.h.duyck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Reviewed-by: NShuah Khan <shuah.khan@hp.com>
Tested-by: NShuah Khan <shuah.khan@hp.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

dma-debug depends on get_dma_ops() interface. Several architectures
do not define dma_ops and get_dma_ops(). When dma debug interfaces are
used on an architecture (e.g: c6x) that doesn't define get_dmap_ops(),
compilation fails. Changing dma-debug to call dma_mapping_error() instead
of defining its own that calls get_dma_ops(), such that the internal use of
dma_mapping_error() doesn't interfere with the debug_dma_mapping_error()
interface's mapping error checks. Moving dma_mapping_error() checks in
check_unmap() under the dma debug entry not found is sufficient to fix the
problem.

Reference: https://lkml.org/lkml/2012/10/26/367Signed-off-by: NShuah Khan <shuah.khan@hp.com>
Reported-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NJoerg Roedel <joro@8bytes.org>

Add dma-debug interface debug_dma_mapping_error() to debug
drivers that fail to check dma mapping errors on addresses
returned by dma_map_single() and dma_map_page() interfaces.
This interface clears a flag set by debug_dma_map_page() to
indicate that dma_mapping_error() has been called by the
driver. When driver does unmap, debug_dma_unmap() checks the
flag and if this flag is still set, prints warning message
that includes call trace that leads up to the unmap. This
interface can be called from dma_mapping_error() routines to
enable dma mapping error check debugging.

Tested: Intel iommu and swiotlb (iommu=soft) on x86-64 with
        CONFIG_DMA_API_DEBUG enabled and disabled.
Signed-off-by: NShuah Khan <shuah.khan@hp.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

If there is only one match, the unique matched entry should be returned.

Without the fix, the upcoming dma debug interfaces ("dma-debug: new
interfaces to debug dma mapping errors") can't work reliably because
only device and dma_addr are passed to dma_mapping_error().
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Reported-by: NWu Fengguang <fengguang.wu@intel.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Tested-by: NShuah Khan <shuah.khan@hp.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove local BUS_NOTIFY_UNBOUND_DRIVER define. This is not used since
BUS_NOTIFY_UNBOUND_DRIVER is defined in include/linux/device.h
Signed-off-by: NShuah Khan <shuah.khan@hp.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Even though it has "bool" in the name, you have pass a u32 pointer to
debugfs_create_bool().  Otherwise you get memory corruption in
write_file_bool().  Fortunately in this case the corruption happens in
an alignment hole between variables so it doesn't cause any problems.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Saving stack trace can take a while and once the entry
is allocated free_entries_lock is no longer needed.
Signed-off-by: NJakub Kicinski <kubakici@wp.pl>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

As part of the removal of get_driver()/put_driver(), this patch
(as1512) gets rid of various useless and unnecessary calls in several
drivers.  In some cases it may be desirable to pin the driver by
calling try_module_get(), but that can be done later.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
CC: "David S. Miller" <davem@davemloft.net>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Michael Buesch <m@bues.ch>
CC: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

cppcheck reported:
[lib/dma-debug.c:248] -> [lib/dma-debug.c:248]: (style) Same expression on both sides of '=='.
Signed-off-by: NThomas Jarosch <thomas.jarosch@intra2net.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

There are no modular calls here, so just the minimal header for
the EXPORT_SYMBOL macro will suffice.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Summary:
Users of the pci_dma_sync_single_* api allow users to sync address ranges within
the range of a mapped entry (i.e. you can dma map address X to dma_addr_t A and
then pci_dma_sync_single on dma_addr_t A+1.  The dma-debug library however
assume dma syncs will always occur using the base address of a mapped region,
and uses that assumption to find entries in its hash table.  Since thats often
(but not always the case), the dma debug library can give us false errors about
missing entries, which are reported as syncing of memory not allocated by the
driver.  This was noted in the cxgb3 driver as this error:

WARNING: at lib/dma-debug.c:902 check_sync+0xdd/0x48c()
Hardware name: To be filled by O.E.M.
cxgb3 0000:01:00.0: DMA-API: device driver tries to sync DMA memory it has not
allocated [device address=0x00000000fff97800] [size=1984 bytes]
Modules linked in: autofs4 sunrpc cpufreq_ondemand acpi_cpufreq freq_table
mperf ip6t_REJECT nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6 uinput
snd_hda_codec_intelhdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec
snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer e1000e snd soundcore r8169
cxgb3 iTCO_wdt snd_page_alloc mii shpchp i2c_i801 iTCO_vendor_support mdio
microcode firewire_ohci firewire_core crc_itu_t ata_generic pata_acpi i915
drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded:
scsi_wait_scan]
Pid: 1818, comm: ifconfig Not tainted 2.6.35-0.23.rc3.git6.fc14.x86_64 #1
Call Trace:
[<ffffffff81050f71>] warn_slowpath_common+0x85/0x9d
[<ffffffff8105102c>] warn_slowpath_fmt+0x46/0x48
[<ffffffff8124658e>] ? check_sync+0x39/0x48c
[<ffffffff8107c470>] ? trace_hardirqs_on+0xd/0xf
[<ffffffff81246632>] check_sync+0xdd/0x48c
[<ffffffff81246ca6>] debug_dma_sync_single_for_device+0x3f/0x41
[<ffffffffa011615c>] ? pci_map_page+0x84/0x97 [cxgb3]
[<ffffffffa0117bc3>] pci_dma_sync_single_for_device.clone.0+0x65/0x6e [cxgb3]
[<ffffffffa0117ed1>] refill_fl+0x305/0x30a [cxgb3]
[<ffffffffa011857d>] t3_sge_alloc_qset+0x6a7/0x821 [cxgb3]
[<ffffffffa010a07b>] cxgb_up+0x4d0/0xe62 [cxgb3]
[<ffffffff81086037>] ? __module_text_address+0x12/0x58
[<ffffffffa010aa4c>] cxgb_open+0x3f/0x309 [cxgb3]
[<ffffffff813e9f6c>] __dev_open+0x8e/0xbc
[<ffffffff813e7ca5>] __dev_change_flags+0xbe/0x142
[<ffffffff813e9ea8>] dev_change_flags+0x21/0x57
[<ffffffff81445937>] devinet_ioctl+0x29a/0x54b
[<ffffffff811f9a87>] ? inode_has_perm+0xaa/0xce
[<ffffffff81446ed2>] inet_ioctl+0x8f/0xa7
[<ffffffff813d683a>] sock_do_ioctl+0x29/0x48
[<ffffffff813d6c83>] sock_ioctl+0x213/0x222
[<ffffffff81137f78>] vfs_ioctl+0x32/0xa6
[<ffffffff811384e2>] do_vfs_ioctl+0x47a/0x4b3
[<ffffffff81138571>] sys_ioctl+0x56/0x79
[<ffffffff81009c32>] system_call_fastpath+0x16/0x1b
---[ end trace 69a4d4cc77b58004 ]---

(some edits by Joerg Roedel)
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Reported-by: NJay Fenalson <fenlason@redhat.com>
CC: Divy LeRay <divy@chelsio.com>
CC: Stanislaw Gruszka <sgruszka@redhat.com>
CC: Joerg Roedel <joerg.roedel@amd.com>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

When driver leak dma mapping, print additional information about one of
leaked entries, to to help investigate problem. Patch should be useful
for debugging drivers, which maps many different class of buffers.
Signed-off-by: NStanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>

Earlier in this function we set the last byte of "buf" to NULL so we
always hit the break statement and "i" is never equal to NAME_MAX_LEN.
This patch doesn't change how the driver works but it silences a Smatch
warning and it makes it clearer that we don't write past the end of the
array.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

warning: symbol 'filter_fops' was not declared. Should it be static?
Signed-off-by: NThiago Farina <tfransosi@gmail.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

There is no need to perform full BIDIR sync (copying the buffers in case
of swiotlb and similar schemes) if we know that the owner (CPU or device)
hasn't altered the data.

Addresses the false-positive reported at
http://bugzilla.kernel.org/show_bug.cgi?id=14169Signed-off-by: NKrzysztof Halasa <khc@pm.waw.pl>
Cc: David Miller <davem@davemloft.net>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Stephen Rothwell reported the following build warning:

 lib/dma-debug.c: In function 'dma_debug_device_change':
 lib/dma-debug.c:680: warning: 'return' with no value, in function returning non-void

Introduced by commit f797d988
("dma-debug: Do not add notifier when dma debugging is disabled").

Return 0 [notify-done] when disabled. (this is standard bus notifier behavior.)
Signed-off-by: NShaun Ruffell <sruffell@digium.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@kernel.org>
LKML-Reference: <20091231125624.GA14666@liondog.tnic>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

If CONFIG_HAVE_DMA_API_DEBUG is defined and "dma_debug=off" is
specified on the kernel command line, when you detach a driver from a
device you can cause the following NULL pointer dereference:

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c0580d35>] dma_debug_device_change+0x5d/0x117

The problem is that the dma_debug_device_change notifier function is
added to the bus notifier chain even though the dma_entry_hash array
was never initialized.  If dma debugging is disabled, this patch both
prevents dma_debug_device_change notifiers from being added to the
chain, and additionally ensures that the dma_debug_device_change
notifier function is a no-op.

Cc: stable@kernel.org
Signed-off-by: NShaun Ruffell <sruffell@digium.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

When PAE is enabled in the kernel configuration the size of
phys_addr_t differs from the size of a void pointer. The gcc
prints a warning about that in dma-debug code.
This patch fixes the warning by converting the output to
unsigned long long instead of a pointer.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

While it's debatable whether or not a NULL device argument to
the DMA API functions is valid... since it certainly isn't
valid on devices with an IOMMU... dma-debug really shouldn't be
dereferencing null pointers either.

Guard against that in err_printk and the driver_filter
functions. A Fedora rawhide user was seeing this in one of the
dvb drivers resulting in an oops on boot.

[ A patch has been sent for testing to the driver, but I feel
  the dma debugging support should be fixed as well. (There's
  still a pile of legacy garbage in the kernel passing null
  pointers to dma_{alloc,free}_*. :( ]
Signed-off-by: NKyle McMartin <kyle@redhat.com>
Cc: mchehab@infradead.org
Cc: Joerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20090820011708.GP25206@bombadil.infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Linus noticed how unclean and buggy the overlap() function is:

 - It uses convoluted (and bug-causing) positive checks for
   range overlap - instead of using a more natural negative
   check.

 - Even the positive checks are buggy: a positive intersection
   check has four natural cases while we checked only for three,
   missing the (addr < start && addr2 == end) case for example.

 - The variables are mis-named, making it non-obvious how the
   check was done.

 - It needlessly uses u64 instead of unsigned long. Since these
   are kernel memory pointers and we explicitly exclude highmem
   ranges anyway we cannot ever overflow 32 bits, even if we
   could. (and on 64-bit it doesnt matter anyway)

All in one, this function needs a total revamp. I used Linus's
suggestions minus the paranoid checks (we cannot overflow really
because if we get totally bad DMA ranges passed far more things
break in the systems than just DMA debugging). I also fixed a
few other small details i noticed.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Alan Cox reported that lockdep runs out of its stack-trace entries
with certain configs:

 BUG: MAX_STACK_TRACE_ENTRIES too low

This happens because there are 1024 hash buckets, each with a
separate lock. Lockdep puts each lock into a separate lock class and
tracks them independently.

But in reality we never take more than one of the buckets, so they
really belong into a single lock-class. Annotate the has bucket lock
init accordingly.

[ Impact: reduce the lockdep footprint of dma-debug ]
Reported-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

This patch fixes a bug in the overlap function which returned true if
one region ends exactly before the second region begins. This is no
overlap but the function returned true in that case.

Cc: stable@kernel.org
Reported-by: NAndrew Randrianasulu <randrik@mail.ru>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

The current code is not very careful when it builds reference
dma_debug_entries which get passed to hash_bucket_find(). But since this
function changed to a best-fit algorithm these entries have to be more
acurate. This patch adds this higher level of accuracy.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

If we don't check for sg_call_ents the hash_bucket_find function might
still return the wrong dma_debug_entry for sg mappings.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

This patch makes the driver_filter function more readable by
reorganizing the code. The removal of a code code block to an upper
indentation level makes hard-to-read line-wraps unnecessary.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

There is no need to disable/enable irqs on each loop iteration. Just
disable irqs for the whole time the loop runs.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

The pr_* macros are shorter than the old printk(KERN_ ...) variant.
Change the dma-debug code to use the new macros and save a few
unnecessary line breaks. If lines don't break the source code can also
be grepped more easily.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

This patch changes the recent updates to dma-debug to conform with
coding style guidelines of Linux and the -tip tree.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Last patch series introduced some new comment which does not fit the
Kernel comment style guidelines. Fix it with this patch.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Some device drivers map the same physical address multiple times to a
dma address. Without an IOMMU this results in the same dma address being
put into the dma-debug hash multiple times. With a first-fit match in
hash_bucket_find() this function may return the wrong dma_debug_entry.

This can result in false positive warnings. This patch fixes it by
changing the first-fit behavior of hash_bucket_find() into a best-fit
algorithm.
Reported-by: NTorsten Kaiser <just.for.lkml@googlemail.com>
Reported-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Cc: lethal@linux-sh.org
Cc: just.for.lkml@googlemail.com
Cc: hancockrwd@gmail.com
Cc: jens.axboe@oracle.com
Cc: bharrosh@panasas.com
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@kernel.org>
LKML-Reference: <20090605104132.GE24836@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch add the dma_debug_driver= boot parameter to enable the driver
filter for early boot.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

This patch adds the dma-api/driver_filter file to debugfs. The root user
can write a driver name into this file to see only dma-api errors for
that particular driver in the kernel log. Writing an empty string to
that file disables the driver filter.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

This patch adds the state variables for the driver filter and a function
to check if the filter is enabled and matches to the current device. The
check is built into the err_printk function.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

DMA-mapping.txt says that debug_dma_sync_sg family must be called with
the _same_ one you passed into the dma_map_sg call, it should _NOT_ be
the 'count' value _returned_ from the dma_map_sg call.

debug_dma_sync_sg_for_cpu and debug_dma_sync_sg_for_device can't
handle this properly; they need to use the sg_mapped_ents in struct
dma_debug_entry as debug_dma_unmap_sg() does.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

debug_dma_map_sg() and debug_dma_unmap_sg() use length in struct
scatterlist while debug_dma_sync_sg_for_cpu() and
debug_dma_sync_sg_for_device() use dma_length. This causes bugs
warnings on some IOMMU implementations since these values are not
same; the length doesn't represent the dma length.

We always need to use sg_dma_len() accessor to get the dma length of a
scatterlist entry.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

Architectures might not have dma_address in struct scatterlist (PARISC
doesn't). Directly accessing to dma_address in struct scatterlist is
wrong; we need to use sg_dma_address() accesssor instead.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

This is basically a revert of commit 314eeac9 but now in a
fixed version.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

The feature needs some more work because the notfier which is used to
check for pending allocations is called before the device drivers
->remove() function. Therefore this feature reports false positives.

A real fix for this issue is to introduce a new notifier event which sent
_after_ the driver has deinitialized itself. That will done for the next
kernel version.

[ Impact: reduce the scope of CONFIG_DMA_API_DEBUG=y checks ]
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Cc: iommu@lists.linux-foundation.org
LKML-Reference: <1240576557-22442-1-git-send-email-joerg.roedel@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>