linux-stable.git/drivers/mtd/mtdchar.c, branch linux-3.1.y

mtd: mtdchar: add missing initializer on raw write

2011-11-11T17:44:45+00:00

commit bf5140817b2d65faac9b32fc9057a097044ac35b upstream.

On writes in MODE_RAW the mtd_oob_ops struct is not sufficiently
initialized which may cause nandwrite to fail. With this patch
it is possible to write raw nand/oob data without additional ECC
(either for testing or when some sectors need different oob layout
e.g. bootloader) like
nandwrite  -n -r -o  /dev/mtd0 

Signed-off-by: Peter Wippich 
Tested-by: Ricard Wanderlof 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: Greg Kroah-Hartman

VFS : mount lock scalability for internal mounts

2011-07-24T14:08:32+00:00

For a number of file systems that don't have a mount point (e.g. sockfs
and pipefs), they are not marked as long term. Therefore in
mntput_no_expire, all locks in vfs_mount lock are taken instead of just
local cpu's lock to aggregate reference counts when we release
reference to file objects.  In fact, only local lock need to have been
taken to update ref counts as these file systems are in no danger of
going away until we are ready to unregister them.

The attached patch marks file systems using kern_mount without
mount point as long term.  The contentions of vfs_mount lock
is now eliminated.  Before un-registering such file system,
kern_unmount should be called to remove the long term flag and
make the mount point ready to be freed.

Signed-off-by: Tim Chen 
Signed-off-by: Al Viro

mtd: kill CONFIG_MTD_PARTITIONS

2011-05-25T01:25:35+00:00

Now that none of the drivers use CONFIG_MTD_PARTITIONS we can remove
it from Kconfig and the last remaining uses.

Signed-off-by: Jamie Iles 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: mtdchar: retry large buffer allocations

2011-05-25T01:00:45+00:00

Replace direct call to kmalloc for a potentially large, contiguous
buffer allocation with one to mtd_kmalloc_up_to which helps ensure the
operation can succeed under low-memory, highly- fragmented situations
albeit somewhat more slowly.

Signed-off-by: Grant Erickson 
Tested-by: Ben Gardiner 
Tested-by: Stefano Babic 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi

Merge git://git.infradead.org/mtd-2.6

2011-01-17T19:15:30+00:00

* git://git.infradead.org/mtd-2.6: (59 commits)
  mtd: mtdpart: disallow reading OOB past the end of the partition
  mtd: pxa3xx_nand: NULL dereference in pxa3xx_nand_probe
  UBI: use mtd->writebufsize to set minimal I/O unit size
  mtd: initialize writebufsize in the MTD object of a partition
  mtd: onenand: add mtd->writebufsize initialization
  mtd: nand: add mtd->writebufsize initialization
  mtd: cfi: add writebufsize initialization
  mtd: add writebufsize field to mtd_info struct
  mtd: OneNAND: OMAP2/3: prevent regulator sleeping while OneNAND is in use
  mtd: OneNAND: add enable / disable methods to onenand_chip
  mtd: m25p80: Fix JEDEC ID for AT26DF321
  mtd: txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max)
  mtd: cfi_cmdset_0002: add support for Samsung K8D3x16UxC NOR chips
  mtd: cfi_cmdset_0002: add support for Samsung K8D6x16UxM NOR chips
  mtd: nand: ams-delta: drop omap_read/write, use ioremap
  mtd: m25p80: add debugging trace in sst_write
  mtd: nand: ams-delta: select for built-in by default
  mtd: OneNAND: lighten scary initial bad block messages
  mtd: OneNAND: OMAP2/3: add support for command line partitioning
  mtd: nand: rearrange ONFI revision checking, add ONFI 2.3
  ...

Fix up trivial conflict in drivers/mtd/Kconfig as per DavidW.

sanitize vfsmount refcounting changes

2011-01-16T18:47:07+00:00

Instead of splitting refcount between (per-cpu) mnt_count
and (SMP-only) mnt_longrefs, make all references contribute
to mnt_count again and keep track of how many are longterm
ones.

Accounting rules for longterm count:
	* 1 for each fs_struct.root.mnt
	* 1 for each fs_struct.pwd.mnt
	* 1 for having non-NULL ->mnt_ns
	* decrement to 0 happens only under vfsmount lock exclusive

That allows nice common case for mntput() - since we can't drop the
final reference until after mnt_longterm has reached 0 due to the rules
above, mntput() can grab vfsmount lock shared and check mnt_longterm.
If it turns out to be non-zero (which is the common case), we know
that this is not the final mntput() and can just blindly decrement
percpu mnt_count.  Otherwise we grab vfsmount lock exclusive and
do usual decrement-and-check of percpu mnt_count.

For fs_struct.c we have mnt_make_longterm() and mnt_make_shortterm();
namespace.c uses the latter in places where we don't already hold
vfsmount lock exclusive and opencodes a few remaining spots where
we need to manipulate mnt_longterm.

Note that we mostly revert the code outside of fs/namespace.c back
to what we used to have; in particular, normal code doesn't need
to care about two kinds of references, etc.  And we get to keep
the optimization Nick's variant had bought us...

Signed-off-by: Al Viro

pass default dentry_operations to mount_pseudo()

2011-01-13T01:03:43+00:00

Signed-off-by: Al Viro

fs: scale mntget/mntput

2011-01-07T06:50:33+00:00

The problem that this patch aims to fix is vfsmount refcounting scalability.
We need to take a reference on the vfsmount for every successful path lookup,
which often go to the same mount point.

The fundamental difficulty is that a "simple" reference count can never be made
scalable, because any time a reference is dropped, we must check whether that
was the last reference. To do that requires communication with all other CPUs
that may have taken a reference count.

We can make refcounts more scalable in a couple of ways, involving keeping
distributed counters, and checking for the global-zero condition less
frequently.

- check the global sum once every interval (this will delay zero detection
  for some interval, so it's probably a showstopper for vfsmounts).

- keep a local count and only taking the global sum when local reaches 0 (this
  is difficult for vfsmounts, because we can't hold preempt off for the life of
  a reference, so a counter would need to be per-thread or tied strongly to a
  particular CPU which requires more locking).

- keep a local difference of increments and decrements, which allows us to sum
  the total difference and hence find the refcount when summing all CPUs. Then,
  keep a single integer "long" refcount for slow and long lasting references,
  and only take the global sum of local counters when the long refcount is 0.

This last scheme is what I implemented here. Attached mounts and process root
and working directory references are "long" references, and everything else is
a short reference.

This allows scalable vfsmount references during path walking over mounted
subtrees and unattached (lazy umounted) mounts with processes still running
in them.

This results in one fewer atomic op in the fastpath: mntget is now just a
per-CPU inc, rather than an atomic inc; and mntput just requires a spinlock
and non-atomic decrement in the common case. However code is otherwise bigger
and heavier, so single threaded performance is basically a wash.

Signed-off-by: Nick Piggin

mtd: fix master device identification for mtd repartition

2010-12-03T16:32:35+00:00

Function mtd_has_master renamed as mtd_is_partition to follow the function logic.
The patch fixes the problem of checking the right mtd device for partition creation.
To delete partition checking is not needed here so as it is done in mtd_del_partition.
By master we consider the mtd device which does not belong to any partition.

Signed-off-by: Roman Tereshonkov 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse