There is a surprisingly large number of tutorials
that suggest using mtdblock to mount SquashFS filesystems
on flash devices, including NAND devices.
This approach is suboptimal than using UBI. If the flash device
is NAND, this is specially true, due to wear leveling, bit-flips and
badblocks. In this case UBI is strongly preferred, so be nice to users
and print a warning suggesting to consider UBI block, if mtdblock
is added for a NAND device.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210801234509.18774-8-ezequiel@collabora.com
Removing some boilerplate by using module_mtd_blktrans instead of calling
register and unregister in the otherwise empty init/exit functions.
Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210213164600.409061-5-zhengdejin5@gmail.com
The function call process is as follows:
mtd_blktrans_work()
while (1)
do_blktrans_request()
mtdblock_writesect()
do_cached_write()
write_cached_data() /*if cache_state is STATE_DIRTY*/
erase_write()
write_cached_data() returns failure without modifying cache_state
and cache_offset. So when do_cached_write() is called again,
write_cached_data() will be called again to perform erase_write()
on the same cache_offset.
But if this cache_offset points to a bad block, erase_write() will
always return -EIO. Writing to this mtdblk is equivalent to losing
the current data, and repeatedly writing to the bad block.
Repeatedly writing a bad block has no real benefits,
but brings some negative effects:
1 Lost subsequent data
2 Loss of flash device life
3 erase_write() bad blocks are very time-consuming. For example:
the function do_erase_oneblock() in chips/cfi_cmdset_0020.c or
chips/cfi_cmdset_0002.c may take more than 20 seconds to return
Therefore, when erase_write() returns -EIO in write_cached_data(),
clear cache_state to avoid writing to bad blocks repeatedly.
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The following sequence is problematic:
mtdblock_flush()
-->write_cached_data()
--->erase_write()
mtdblock: erase of region [0x40000, 0x20000] on "xxx" failed
Problem is: mtdblock_flush() always returns 0. Indeed, even if
write_cached_data() fails and data is not written to the device,
syscall_write() still returns success. Avoid this situation by
actually returning the error coming out of write_cached_data().
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1584674111-101462-1-git-send-email-nixiaoming@huawei.com
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
51 franklin st fifth floor boston ma 02110 1301 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 50 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190523091649.499889647@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Callers of erase_write() always pass an unsigned int.
So this patch avoids a cast to an int.
Signed-off-by: huijin.park <huijin.park@samsung.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
->fail_addr and ->addr can be updated no matter the result of
parent->_erase(), we just need to remove the code doing the same thing
in mtd_erase_callback() to avoid adjusting those fields twice.
Note that this can be done because all MTD users have been converted to
not pass an erase_info->callback() and are thus only taking the
->addr_fail and ->addr fields into account after part_erase() has
returned.
While we're at it, get rid of the erase_info->mtd field which was only
needed to let mtd_erase_callback() get the partition device back.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
None of the mtd->_erase() implementations work in an asynchronous manner,
so let's simplify MTD users that call mtd_erase(). All they need to do
is check the value returned by mtd_erase() and assume that != 0 means
failure.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
The global lock mtdblks_lock was used to protect the original mtdblks
array to avoid race conditions. As the mtdblks array was already gone,
but the mtdblks_lock is left, and it causes latency when open/release dev.
So we need to remove it here.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This patch moves the char and block major number definitions
to major.h to be with the rest of the major numbers.
While doing this, include major.h in the files that need it.
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Both existing instances always return 0 and even if they didn't,
the value would be lost on the way out. Just don't bother...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Because it is useless to call it if the device is opened in R/O mode, and also
harmful: on CFI NOR flash it may block for long time waiting for erase
operations to complete is another partition with a R/W file-system on this
chip.
Artem Bityutskiy: write commit message, amend the patch to match the latest
tree (we use mtd_sync(), not mtd->sync() nowadays).
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This patch teaches 'mtd_sync()' to do nothing when the MTD driver does
not have the '->sync()' method, which allows us to remove all direct
'mtd->sync' accesses.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This patch is part of a patch-set which changes the MTD interface
from 'mtd->func()' form to 'mtd_func()' form. We need this because
we want to add common code to to all drivers in the mtd core level,
which is impossible with the current interface when MTD clients
call driver functions like 'read()' or 'write()' directly.
At this point we just introduce a new inline wrapper function, but
later some of them are expected to gain more code. E.g., the input
parameters check should be moved to the wrappers rather than be
duplicated at many drivers.
This particular patch introduced the 'mtd_erase()' interface. The
following patches add all the other interfaces one by one.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Start moving away from the MTD_DEBUG_LEVEL messages. The dynamic
debugging feature is a generic kernel feature that provides more
flexibility.
(See Documentation/dynamic-debug-howto.txt)
Also fix some punctuation, indentation, and capitalization that went
along with the affected lines.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
mtdblks_lock can be initialized automatically with
DEFINE_MUTEX() rather than explicitly calling mutex_init().
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* Test results of few functions that were declared with __must_check
* Fix bogus gcc warning about uinitialized variable 'ret'
* Remove unused variable from mtdblock_remove_dev
* Don't use deprecated DMA_32BIT_MASK
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* Add locking where it was missing.
* Don't do a get_mtd_device in blktrans_open because it would lead to a
deadlock; instead do that in add_mtd_blktrans_dev.
* Only free the mtd_blktrans_dev structure when the last user exits.
* Flush request queue on device removal.
* Track users, and call tr->release in del_mtd_blktrans_dev
Due to that ->open and release aren't called more that once.
Now it is safe to call del_mtd_blktrans_dev while the device is still in use.
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Since we allocate struct mtd_blktrans_dev for each block device, we
can add our own structure members to the end. Therefore embed
struct mtd_blktrans_dev in struct mtdblk_dev and remove the static
array of struct mtdblk_dev. Also remove the redundant pointer to
struct mtd_info.
This is preparation for removing the static limit on the number of MTD
devices.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Due to problems at cam.org, my nico@cam.org email address is no longer
valid. FRom now on, nico@fluxnic.net should be used instead.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The mtdblks array and its content are prone to race conditions. Introduce
the mutex mtdblks_lock in order to solve this.
[Amended by Artem Bityutskiy]
Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Once upon a time, the MTD repository was using CVS.
This patch therefore removes all usages of the no longer updated CVS
keywords from the MTD code.
This also includes code that printed them to the user.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Currently, mtd_blkdevs enforces a block size of 512, even if the drivers
can seemingly request a different size. This patch fixes mtd_blkdevs so
block sizes other than 512 work correctly.
Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Ram devices get the extra capability of MTD_NO_ERASE - not requiring
an explicit erase before writing to it. Currently only mtdblock uses
this capability. Rest of the patch is a simple text replacement.
Signed-off-by: Joern Engel <joern@wh.fh-wedel.de>
Most of those macros are unused and the used ones just obfuscate
the code. Remove them and fixup all users.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
mtdblock is the only user of aggregate capabilities in mtd. This is clearly
bogus and should be changed. In particular, it tries to determine whether
the device in question is a piece of RAM. For every single driver that fits
the current criteria, an easier test would be to check for the type being
MTD_RAM.
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I recently picked up my older work to remove unnecessary #includes of
sched.h, starting from a patch by Dave Jones to not include sched.h
from module.h. This reduces the number of indirect includes of sched.h
by ~300. Another ~400 pointless direct includes can be removed after
this disentangling (patch to follow later).
However, quite a few indirect includes need to be fixed up for this.
In order to feed the patches through -mm with as little disturbance as
possible, I've split out the fixes I accumulated up to now (complete for
i386 and x86_64, more archs to follow later) and post them before the real
patch. This way this large part of the patch is kept simple with only
adding #includes, and all hunks are independent of each other. So if any
hunk rejects or gets in the way of other patches, just drop it. My scripts
will pick it up again in the next round.
Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Ezequiel Garcia