The cfi_staa_write_buffers function uses a large amount of kernel stack
whenever CONFIG_MTD_MAP_BANK_WIDTH_32 is set, and that results in a
warning on ARM allmodconfig builds:

drivers/mtd/chips/cfi_cmdset_0020.c: In function 'cfi_staa_write_buffers':
drivers/mtd/chips/cfi_cmdset_0020.c:651:1: warning: the frame size of 1208 bytes is larger than 1024 bytes [-Wframe-larger-than=]

It turns out that this is largely a result of a suboptimal implementation
of map_word_andequal(). Replacing this function with a straightforward
one reduces the stack size in this function by exactly 200 bytes,
shrinks the .text segment for this file from 27648 bytes to 26608 bytes,
and makes the warning go away.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

We're not initializing the ooblen field. Our users don't care, since
they check that oobbuf == NULL first, but it's good practice to zero
unused fields out.

We can drop the NULL initializations since we're memset()ing the whole
thing.

Noticed by Coverity, CID #200821, #200822
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

The only exit (break) from the preceding loop is nested within a
condition which yields req == NULL. This code is dead.

Coverity CID #752669
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

TclsRising is always 1.

Caught by Coverity.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>

Coverity noticed that these 'ret' assignments weren't being used. Let's
use them.

Note that nand_lock() and nand_unlock() are still not officially used by
any drivers.

Coverity CIDs #1227054 and #1227037
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Caught by Coverity (CID #200625 and others)
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>

'ret' is always zero, so this is all dead code.

This should quiet Coverity CID #1226739.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>

If no devices were found, we would already have skipped over this code.

Detected by Coverity, CID #744270
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>

The PARAM command was long unimplemented and it probably wasn't
noticed because chip probing using only the few bytes returned by the
READID command are good enough in most cases to determine the chip in
use.

Still to notice such a shortcoming earlier in the future would be nice
in case it's something more vital.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

The mxc-nand driver never supported the PARAM command to read out the
ONFI parameter page and so always relied on probing my manufacturer and
device id (as provided by the READID command).

This patch implements reading out the first parameter page copy at least
which should be good enough in practise.

This makes the boot log change from

	nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xb1
	nand: Micron NAND 128MiB 1,8V 16-bit

to
	nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xb1
	nand: Micron MT29F1G16ABBDAH4

on my machine.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

The mxc-nand controller works pagewise and so usually only sends
commands to the flash chip with column == 0. A request with column != 0
from the upper layer is then fulfilled by indexing appropriately into the
device's RAM buffer.

To be able to access the ONFI marker at offset 0x20 in reply to the
READID command however it's invalid to read 32 bytes starting from
column 0.

So let the function used to send the address cycles send the column
address actually passed instead of 0 and fix all callers to pass 0
instead appropriately. Also add some warnings in case this patch changes
the drivers semantics.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

When the hardware operates in 16 bit mode it always reads 16 bits even
for operations that only have the lower 8 bits defined. So the upper
bits must be discarded. Do this in the read_byte callback instead of
when reading the NAND id to support reading byte wise more than 5 bytes
and at other occations (like reading the ONFI parameter page).
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

At least on i.MX25 (i.e. NFCv2) preset_v2 is called with mtd->writesize
== 0 that is before the connect flash chip is detected. It then
configures for 8 bit ECC mode which needs 26 bytes of OOB per 512 bytes
main section. For flashes with a smaller OOB area issuing a read page
command makes the controller stuck with this config.

Note that this currently doesn't hurt because the first read page
command is issued only after detection is complete and preset is called
once more.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

While extending the mxc-nand driver it happend to me a few times that
the device was stuck and this made the machine hang during boot. So
implement a timeout and print a stack trace the first time this happens
to make it debuggable. The return type of the waiting function is also
changed to int to be able to handle the timeout in the caller.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Currently the driver read NFC command registers to get NFC busy flag.
Actually this flag also can be get by reading HSMC_SR register.

Use the read NFC command registers need mapping a huge memory region.
To save the mapped memory region, we change to check NFC busy flag by
reading HSMC_SR register.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Fix typo, "Unkown" -> "Unknown"
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

s3c2410_nand_probe is not the name of the function.

These prints have little utility, so let's just kill them.
Reported-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

pxa3xx_flash_ids wasn't initialized to 0, which in certain cases could
end up containing corrupted values in its members. Fix this to avoid
possible issues.
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

As the devicetree binding doesn't require num_cs to exist or be strictly
positive, and neither does the platform data case, a bug appear when
num_cs is set to 0 and panics the kernel.

The issue is that in alloc_nand_resource(), chip is dereferenced without
having a value assigned when num_cs == 0.

Fix this by returning ENODEV is num_cs == 0.

The panic seen is :
Unable to handle kernel NULL pointer dereference at virtual address 000002b8
pgd = c0004000
[000002b8] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT ARM
Modules linked in:
Hardware name: Marvell PXA3xx (Device Tree Support)
task: c3822aa0 ti: c3826000 task.ti: c3826000
PC is at alloc_nand_resource+0x180/0x4a8
LR is at alloc_nand_resource+0xa0/0x4a8
pc : [<c0275b90>]    lr : [<c0275ab0>]    psr: 68000013
sp : c3827d90  ip : 00000000  fp : 00000000
r10: c3862200  r9 : 0000005e  r8 : 00000000
r7 : c3865610  r6 : c3862210  r5 : c3924210  r4 : c3862200
r3 : 00000000  r2 : 00000000  r1 : 00000000  r0 : 00000000
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Control: 0000397f  Table: 80004018  DAC: 00000035
Process swapper (pid: 1, stack limit = 0xc3826198)
Stack: (0xc3827d90 to 0xc3828000)
...zip...
[<c0275b90>] (alloc_nand_resource) from [<c0275ff8>] (pxa3xx_nand_probe+0x140/0x978)
[<c0275ff8>] (pxa3xx_nand_probe) from [<c0258c40>] (platform_drv_probe+0x48/0xa4)
[<c0258c40>] (platform_drv_probe) from [<c0257650>] (driver_probe_device+0x80/0x21c)
[<c0257650>] (driver_probe_device) from [<c0257878>] (__driver_attach+0x8c/0x90)
[<c0257878>] (__driver_attach) from [<c0255ec4>] (bus_for_each_dev+0x58/0x88)
[<c0255ec4>] (bus_for_each_dev) from [<c0256ec8>] (bus_add_driver+0xd8/0x1d4)
[<c0256ec8>] (bus_add_driver) from [<c0257f14>] (driver_register+0x78/0xf4)
[<c0257f14>] (driver_register) from [<c00088a8>] (do_one_initcall+0x80/0x1e4)
[<c00088a8>] (do_one_initcall) from [<c048ed08>] (kernel_init_freeable+0xec/0x1b4)
[<c048ed08>] (kernel_init_freeable) from [<c0377d8c>] (kernel_init+0x8/0xe4)
[<c0377d8c>] (kernel_init) from [<c00095f8>] (ret_from_fork+0x14/0x3c)
Code: e503b234 e5953008 e1530001 caffffd1 (e59002b8)
---[ end trace a5770060c8441895 ]---
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Change the handling of the data stage in the driver : don't pump data in
the top-half interrupt, but rather schedule a thread for non dma cases.

This will enable latencies in the data pumping, especially if delays are
required. Moreover platform shall be more reactive as other interrupts
can be served while pumping data.

No throughput degradation was observed, at least on the zylonite
platform, while a slight degradation was being expected.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Tested-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

The NDDB register holds the data that are needed by the read and write
commands.

However, during a read PIO access, the datasheet specifies that after each 32
bytes read in that register, when BCH is enabled, we have to make sure that the
RDDREQ bit is set in the NDSR register.

This fixes an issue that was seen on the Armada 385, and presumably other mvebu
SoCs, when a read on a newly erased page would end up in the driver reporting a
timeout from the NAND.

Cc: <stable@vger.kernel.org> # v3.14
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Ensures that block2mtd is triggered after the block devices are enumerated
at boot time.
This issue is seen on BCM2835 (Raspberry Pi) systems when mounting JFFS2
block2mtd filesystems, probably because of the delay on enumerating a USB
MMC card reader.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Rodrigo Freire <rfreire@redhat.com>
Signed-off-by: Herton Krzesinski <herton@redhat.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

.. after extensive statistical analysis of my G+ polling, I've come to
the inescapable conclusion that internet polls are bad.

Big surprise.

But "Hurr durr I'ma sheep" trounced "I like online polls" by a 62-to-38%
margin, in a poll that people weren't even supposed to participate in.
Who can argue with solid numbers like that? 5,796 votes from people who
can't even follow the most basic directions?

In contrast, "v4.0" beat out "v3.20" by a slimmer margin of 56-to-44%,
but with a total of 29,110 votes right now.

Now, arguably, that vote spread is only about 3,200 votes, which is less
than the almost six thousand votes that the "please ignore" poll got, so
it could be considered noise.

But hey, I asked, so I'll honor the votes.

Pull ext4 fixes from Ted Ts'o:
 "Ext4 bug fixes.

  We also reserved code points for encryption and read-only images (for
  which the implementation is mostly just the reserved code point for a
  read-only feature :-)"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix indirect punch hole corruption
  ext4: ignore journal checksum on remount; don't fail
  ext4: remove duplicate remount check for JOURNAL_CHECKSUM change
  ext4: fix mmap data corruption in nodelalloc mode when blocksize < pagesize
  ext4: support read-only images
  ext4: change to use setup_timer() instead of init_timer()
  ext4: reserve codepoints used by the ext4 encryption feature
  jbd2: complain about descriptor block checksum errors

Pull more vfs updates from Al Viro:
 "Assorted stuff from this cycle.  The big ones here are multilayer
  overlayfs from Miklos and beginning of sorting ->d_inode accesses out
  from David"

* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (51 commits)
  autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocation
  procfs: fix race between symlink removals and traversals
  debugfs: leave freeing a symlink body until inode eviction
  Documentation/filesystems/Locking: ->get_sb() is long gone
  trylock_super(): replacement for grab_super_passive()
  fanotify: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions
  Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions
  VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)
  SELinux: Use d_is_positive() rather than testing dentry->d_inode
  Smack: Use d_is_positive() rather than testing dentry->d_inode
  TOMOYO: Use d_is_dir() rather than d_inode and S_ISDIR()
  Apparmor: Use d_is_positive/negative() rather than testing dentry->d_inode
  Apparmor: mediated_filesystem() should use dentry->d_sb not inode->i_sb
  VFS: Split DCACHE_FILE_TYPE into regular and special types
  VFS: Add a fallthrough flag for marking virtual dentries
  VFS: Add a whiteout dentry type
  VFS: Introduce inode-getting helpers for layered/unioned fs environments
  Infiniband: Fix potential NULL d_inode dereference
  posix_acl: fix reference leaks in posix_acl_create
  autofs4: Wrong format for printing dentry
  ...

Pull ARM fix from Russell King:
 "Just one fix this time around.  __iommu_alloc_buffer() can cause a
  BUG() if dma_alloc_coherent() is called with either __GFP_DMA32 or
  __GFP_HIGHMEM set.  The patch from Alexandre addresses this"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8305/1: DMA: Fix kzalloc flags in __iommu_alloc_buffer()

X-Coverup: just ask spender
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

use_pde()/unuse_pde() in ->follow_link()/->put_link() resp.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

As it is, we have debugfs_remove() racing with symlink traversals.
Supply ->evict_inode() and do freeing there - inode will remain
pinned until we are done with the symlink body.

And rip the idiocy with checking if dentry is positive right after
we'd verified debugfs_positive(), which is a stronger check...

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

I've noticed significant locking contention in memory reclaimer around
sb_lock inside grab_super_passive(). Grab_super_passive() is called from
two places: in icache/dcache shrinkers (function super_cache_scan) and
from writeback (function __writeback_inodes_wb). Both are required for
progress in memory allocator.

Grab_super_passive() acquires sb_lock to increment sb->s_count and check
sb->s_instances. It seems sb->s_umount locked for read is enough here:
super-block deactivation always runs under sb->s_umount locked for write.
Protecting super-block itself isn't a problem: in super_cache_scan() sb
is protected by shrinker_rwsem: it cannot be freed if its slab shrinkers
are still active. Inside writeback super-block comes from inode from bdi
writeback list under wb->list_lock.

This patch removes locking sb_lock and checks s_instances under s_umount:
generic_shutdown_super() unlinks it under sb->s_umount locked for write.
New variant is called trylock_super() and since it only locks semaphore,
callers must call up_read(&sb->s_umount) instead of drop_super(sb) when
they're done.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Fanotify probably doesn't want to watch autodirs so make it use d_can_lookup()
rather than d_is_dir() when checking a dir watch and give an error on fake
directories.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Fix up the following scripted S_ISDIR/S_ISREG/S_ISLNK conversions (or lack
thereof) in cachefiles:

 (1) Cachefiles mostly wants to use d_can_lookup() rather than d_is_dir() as
     it doesn't want to deal with automounts in its cache.

 (2) Coccinelle didn't find S_IS* expressions in ASSERT() statements in
     cachefiles.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Convert the following where appropriate:

 (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry).

 (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry).

 (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry).  This is actually more
     complicated than it appears as some calls should be converted to
     d_can_lookup() instead.  The difference is whether the directory in
     question is a real dir with a ->lookup op or whether it's a fake dir with
     a ->d_automount op.

In some circumstances, we can subsume checks for dentry->d_inode not being
NULL into this, provided we the code isn't in a filesystem that expects
d_inode to be NULL if the dirent really *is* negative (ie. if we're going to
use d_inode() rather than d_backing_inode() to get the inode pointer).

Note that the dentry type field may be set to something other than
DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS
manages the fall-through from a negative dentry to a lower layer.  In such a
case, the dentry type of the negative union dentry is set to the same as the
type of the lower dentry.

However, if you know d_inode is not NULL at the call site, then you can use
the d_is_xxx() functions even in a filesystem.

There is one further complication: a 0,0 chardev dentry may be labelled
DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE.  Strictly, this was
intended for special directory entry types that don't have attached inodes.

The following perl+coccinelle script was used:

use strict;

my @callers;
open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') ||
    die "Can't grep for S_ISDIR and co. callers";
@callers = <$fd>;
close($fd);
unless (@callers) {
    print "No matches\n";
    exit(0);
}

my @cocci = (
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISLNK(E->d_inode->i_mode)',
    '+ d_is_symlink(E)',
    '',
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISDIR(E->d_inode->i_mode)',
    '+ d_is_dir(E)',
    '',
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISREG(E->d_inode->i_mode)',
    '+ d_is_reg(E)' );

my $coccifile = "tmp.sp.cocci";
open($fd, ">$coccifile") || die $coccifile;
print($fd "$_\n") || die $coccifile foreach (@cocci);
close($fd);

foreach my $file (@callers) {
    chomp $file;
    print "Processing ", $file, "\n";
    system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 ||
	die "spatch failed";
}

[AV: overlayfs parts skipped]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Use d_is_positive() rather than testing dentry->d_inode in SELinux to get rid
of direct references to d_inode outside of the VFS.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Use d_is_positive() rather than testing dentry->d_inode in Smack to get rid of
direct references to d_inode outside of the VFS.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Use d_is_dir() rather than d_inode and S_ISDIR().  Note that this will include
fake directories such as automount triggers.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>