gen_pool_alloc_algo() iterates over the chunks of a pool trying to find
a contiguous block of memory that satisfies the allocation request.
The shortcut
if (size > atomic_read(&chunk->avail))
continue;
makes the loop skip over chunks that do not have enough bytes left to
fulfill the request. There are two situations, though, where an
allocation might still fail:
(1) The available memory is not contiguous, i.e. the request cannot
be fulfilled due to external fragmentation.
(2) A race condition. Another thread runs the same code concurrently
and is quicker to grab the available memory.
In those situations, the loop calls pool->algo() to search the entire
chunk, and pool->algo() returns some value that is >= end_bit to
indicate that the search failed. This return value is then assigned to
start_bit. The variables start_bit and end_bit describe the range that
should be searched, and this range should be reset for every chunk that
is searched. Today, the code fails to reset start_bit to 0. As a
result, prefixes of subsequent chunks are ignored. Memory allocations
might fail even though there is plenty of room left in these prefixes of
those other chunks.
Fixes: 7f184275aa ("lib, Make gen_pool memory allocator lockless")
Link: http://lkml.kernel.org/r/1477420604-28918-1-git-send-email-danielmentz@google.com
Signed-off-by: Daniel Mentz <danielmentz@google.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bytes alignment is required to manage some special RAM,
so add gen_pool_first_fit_align to genalloc,
meanwhile add gen_pool_alloc_algo to pass algo in case user
layer using more than one algo, and pass data to
gen_pool_first_fit_align(modify gen_pool_alloc as a wrapper)
Signed-off-by: Zhao Qiang <qiang.zhao@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
This change fills devm_gen_pool_create()/gen_pool_get() "name" argument
stub with contents and extends of_gen_pool_get() functionality on this
basis.
If there is no associated platform device with a device node passed to
of_gen_pool_get(), the function attempts to get a label property or device
node name (= repeats MTD OF partition standard) and seeks for a named
gen_pool registered by device of the parent device node.
The main idea of the change is to allow registration of independent
gen_pools under the same umbrella device, say "partitions" on "storage
device", the original functionality of one "partition" per "storage
device" is untouched.
[akpm@linux-foundation.org: fix constness in devres_find()]
[dan.carpenter@oracle.com: freeing const data pointers]
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change modifies gen_pool_get() and devm_gen_pool_create() client
interfaces adding one more argument "name" of a gen_pool object.
Due to implementation gen_pool_get() is capable to retrieve only one
gen_pool associated with a device even if multiple gen_pools are created,
fortunately right at the moment it is sufficient for the clients, hence
provide NULL as a valid argument on both producer devm_gen_pool_create()
and consumer gen_pool_get() sides.
Because only one created gen_pool per device is addressable, explicitly
add a restriction to devm_gen_pool_create() to create only one gen_pool
per device, this implies two possible error codes returned by the
function, account it on client side (only misc/sram). This completes
client side changes related to genalloc updates.
[akpm@linux-foundation.org: gen_pool_get() cleanup]
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To be consistent with other kernel interface namings, rename
of_get_named_gen_pool() to of_gen_pool_get(). In the original function
name "_named" suffix references to a device tree property, which contains
a phandle to a device and the corresponding device driver is assumed to
register a gen_pool object.
Due to a weak relation and to avoid any confusion (e.g. in future
possible scenario if gen_pool objects are named) the suffix is removed.
[sfr@canb.auug.org.au: crypto/marvell/cesa - fix up for of_get_named_gen_pool() rename]
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To be consistent with other genalloc interface namings, rename
dev_get_gen_pool() to gen_pool_get(). The original omitted "dev_" prefix
is removed, since it points to argument type of the function, and so it
does not bring any useful information.
[akpm@linux-foundation.org: update arch/arm/mach-socfpga/pm.c]
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Mark Brown <broonie@kernel.org>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Alan Tull <atull@opensource.altera.com>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
devm_gen_pool_create() calls devres_alloc() and dereferences its result
without checking whether devres_alloc() succeeded. Check for error and
bail out if it happened.
Coverity-id 1016493.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the gen_pool_dma_alloc() the dma pointer can be NULL and while
assigning gen_pool_virt_to_phys(pool, vaddr) to dma caused the following
crash on da850 evm:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
Internal error: Oops: 805 [#1] PREEMPT ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Tainted: G W 3.13.0-rc1-00001-g0609e45-dirty #5
task: c4830000 ti: c4832000 task.ti: c4832000
PC is at gen_pool_dma_alloc+0x30/0x3c
LR is at gen_pool_virt_to_phys+0x74/0x80
Process swapper, call trace:
gen_pool_dma_alloc+0x30/0x3c
davinci_pm_probe+0x40/0xa8
platform_drv_probe+0x1c/0x4c
driver_probe_device+0x98/0x22c
__driver_attach+0x8c/0x90
bus_for_each_dev+0x6c/0x8c
bus_add_driver+0x124/0x1d4
driver_register+0x78/0xf8
platform_driver_probe+0x20/0xa4
davinci_init_late+0xc/0x14
init_machine_late+0x1c/0x28
do_one_initcall+0x34/0x15c
kernel_init_freeable+0xe4/0x1ac
kernel_init+0x8/0xec
This patch fixes the above.
[akpm@linux-foundation.org: update kerneldoc]
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Nicolin Chen <b42378@freescale.com>
Cc: Joe Perches <joe@perches.com>
Cc: Sachin Kamat <sachin.kamat@linaro.org>
Cc: <stable@vger.kernel.org> [3.13.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The documentation mentions a "name" parameter, which does not exist. This
commit removes such mention from the function documentation.
Signed-off-by: Emilio López <emilio@elopez.com.ar>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In struct gen_pool_chunk, end_addr means the end address of memory chunk
(inclusive), but in the implementation it is treated as address + size of
memory chunk (exclusive), so it points to the address plus one instead of
correct ending address.
The ending address of memory chunk plus one will cause overflow on the
memory chunk including the last address of memory map, e.g. when starting
address is 0xFFF00000 and size is 0x100000 on 32bit machine, ending
address will be 0x100000000.
Use correct ending address like starting address + size - 1.
[akpm@linux-foundation.org: add comment to struct gen_pool_chunk:end_addr]
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds three exported functions to lib/genalloc.c:
devm_gen_pool_create, dev_get_gen_pool, and of_get_named_gen_pool.
devm_gen_pool_create is a managed version of gen_pool_create that keeps
track of the pool via devres and allows the management code to
automatically destroy it after device removal.
dev_get_gen_pool retrieves the gen_pool for a given device, if it was
created with devm_gen_pool_create, using devres_find.
of_get_named_gen_pool retrieves the gen_pool for a given device node and
property name, where the property must contain a phandle pointing to a
platform device node. The corresponding platform device is then fed into
dev_get_gen_pool and the resulting gen_pool is returned.
[akpm@linux-foundation.org: make the of_get_named_gen_pool() stub static, fixing a zillion link errors]
[akpm@linux-foundation.org: squish "struct device declared inside parameter list" warning]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Michal Simek <monstr@monstr.eu>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Matt Porter <mporter@ti.com>
Cc: Dong Aisheng <dong.aisheng@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Javier Martin <javier.martin@vista-silicon.com>
Cc: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The genalloc code uses the bitmap API from include/linux/bitmap.h and
lib/bitmap.c, which is based on long values. Both bitmap_set from
lib/bitmap.c and bitmap_set_ll, which is the lockless version from
genalloc.c, use BITMAP_LAST_WORD_MASK to set the first bits in a long in
the bitmap.
That one uses (1 << bits) - 1, 0b111, if you are setting the first three
bits. This means that the API counts from the least significant bits
(LSB from now on) to the MSB. The LSB in the first long is bit 0, then.
The same works for the lookup functions.
The genalloc code uses longs for the bitmap, as it should. In
include/linux/genalloc.h, struct gen_pool_chunk has unsigned long
bits[0] as its last member. When allocating the struct, genalloc should
reserve enough space for the bitmap. This should be a proper number of
longs that can fit the amount of bits in the bitmap.
However, genalloc allocates an integer number of bytes that fit the
amount of bits, but may not be an integer amount of longs. 9 bytes, for
example, could be allocated for 70 bits.
This is a problem in itself if the Least Significat Bit in a long is in
the byte with the largest address, which happens in Big Endian machines.
This means genalloc is not allocating the byte in which it will try to
set or check for a bit.
This may end up in memory corruption, where genalloc will try to set the
bits it has not allocated. In fact, genalloc may not set these bits
because it may find them already set, because they were not zeroed since
they were not allocated. And that's what causes a BUG when
gen_pool_destroy is called and check for any set bits.
What really happens is that genalloc uses kmalloc_node with __GFP_ZERO
on gen_pool_add_virt. With SLAB and SLUB, this means the whole slab
will be cleared, not only the requested bytes. Since struct
gen_pool_chunk has a size that is a multiple of 8, and slab sizes are
multiples of 8, we get lucky and allocate and clear the right amount of
bytes.
Hower, this is not the case with SLOB or with older code that did memset
after allocating instead of using __GFP_ZERO.
So, a simple module as this (running 3.6.0), will cause a crash when
rmmod'ed.
[root@phantom-lp2 foo]# cat foo.c
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/genalloc.h>
MODULE_LICENSE("GPL");
MODULE_VERSION("0.1");
static struct gen_pool *foo_pool;
static __init int foo_init(void)
{
int ret;
foo_pool = gen_pool_create(10, -1);
if (!foo_pool)
return -ENOMEM;
ret = gen_pool_add(foo_pool, 0xa0000000, 32 << 10, -1);
if (ret) {
gen_pool_destroy(foo_pool);
return ret;
}
return 0;
}
static __exit void foo_exit(void)
{
gen_pool_destroy(foo_pool);
}
module_init(foo_init);
module_exit(foo_exit);
[root@phantom-lp2 foo]# zcat /proc/config.gz | grep SLOB
CONFIG_SLOB=y
[root@phantom-lp2 foo]# insmod ./foo.ko
[root@phantom-lp2 foo]# rmmod foo
------------[ cut here ]------------
kernel BUG at lib/genalloc.c:243!
cpu 0x4: Vector: 700 (Program Check) at [c0000000bb0e7960]
pc: c0000000003cb50c: .gen_pool_destroy+0xac/0x110
lr: c0000000003cb4fc: .gen_pool_destroy+0x9c/0x110
sp: c0000000bb0e7be0
msr: 8000000000029032
current = 0xc0000000bb0e0000
paca = 0xc000000006d30e00 softe: 0 irq_happened: 0x01
pid = 13044, comm = rmmod
kernel BUG at lib/genalloc.c:243!
[c0000000bb0e7ca0] d000000004b00020 .foo_exit+0x20/0x38 [foo]
[c0000000bb0e7d20] c0000000000dff98 .SyS_delete_module+0x1a8/0x290
[c0000000bb0e7e30] c0000000000097d4 syscall_exit+0x0/0x94
--- Exception: c00 (System Call) at 000000800753d1a0
SP (fffd0b0e640) is in userspace
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Benjamin Gaignard <benjamin.gaignard@stericsson.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Premit use of another algorithm than the default first-fit one. For
example a custom algorithm could be used to manage alignment requirements.
As I can't predict all the possible requirements/needs for all allocation
uses cases, I add a "free" field 'void *data' to pass any needed
information to the allocation function. For example 'data' could be used
to handle a structure where you store the alignment, the expected memory
bank, the requester device, or any information that could influence the
allocation algorithm.
An usage example may look like this:
struct my_pool_constraints {
int align;
int bank;
...
};
unsigned long my_custom_algo(unsigned long *map, unsigned long size,
unsigned long start, unsigned int nr, void *data)
{
struct my_pool_constraints *constraints = data;
...
deal with allocation contraints
...
return the index in bitmap where perform the allocation
}
void create_my_pool()
{
struct my_pool_constraints c;
struct gen_pool *pool = gen_pool_create(...);
gen_pool_add(pool, ...);
gen_pool_set_algo(pool, my_custom_algo, &c);
}
Add of best-fit algorithm function:
most of the time best-fit is slower then first-fit but memory fragmentation
is lower. The random buffer allocation/free tests don't show any arithmetic
relation between the allocation time and fragmentation but the
best-fit algorithm
is sometime able to perform the allocation when the first-fit can't.
This new algorithm help to remove static allocations on ESRAM, a small but
fast on-chip RAM of few KB, used for high-performance uses cases like DMA
linked lists, graphic accelerators, encoders/decoders. On the Ux500
(in the ARM tree) we have define 5 ESRAM banks of 128 KB each and use of
static allocations becomes unmaintainable:
cd arch/arm/mach-ux500 && grep -r ESRAM .
./include/mach/db8500-regs.h:/* Base address and bank offsets for ESRAM */
./include/mach/db8500-regs.h:#define U8500_ESRAM_BASE 0x40000000
./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK_SIZE 0x00020000
./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK0 U8500_ESRAM_BASE
./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK1 (U8500_ESRAM_BASE + U8500_ESRAM_BANK_SIZE)
./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK2 (U8500_ESRAM_BANK1 + U8500_ESRAM_BANK_SIZE)
./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK3 (U8500_ESRAM_BANK2 + U8500_ESRAM_BANK_SIZE)
./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK4 (U8500_ESRAM_BANK3 + U8500_ESRAM_BANK_SIZE)
./include/mach/db8500-regs.h:#define U8500_ESRAM_DMA_LCPA_OFFSET 0x10000
./include/mach/db8500-regs.h:#define U8500_DMA_LCPA_BASE
(U8500_ESRAM_BANK0 + U8500_ESRAM_DMA_LCPA_OFFSET)
./include/mach/db8500-regs.h:#define U8500_DMA_LCLA_BASE U8500_ESRAM_BANK4
I want to use genalloc to do dynamic allocations but I need to be able to
fine tune the allocation algorithm. I my case best-fit algorithm give
better results than first-fit, but it will not be true for every use case.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@stericsson.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include. Fix up any implicit
include dependencies that were being masked by module.h along
the way.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
