1
linux/drivers
Sonny Rao 04a85d1234 powerpc/BSR: Fix BSR to allow mmap of small BSR on 64k kernel
On Mon, Nov 17, 2008 at 01:26:13AM -0600, Sonny Rao wrote:
> On Fri, Nov 07, 2008 at 04:28:29PM +1100, Paul Mackerras wrote:
> > Sonny Rao writes:
> >
> > > Fix the BSR driver to allow small BSR devices, which are limited to a
> > > single 4k space, on a 64k page kernel.  Previously the driver would
> > > reject the mmap since the size was smaller than PAGESIZE (or because
> > > the size was greater than the size of the device).  Now, we check for
> > > this case use remap_4k_pfn(). Also, take out code to set vm_flags,
> > > as the remap_pfn functions will do this for us.
> >
> > Thanks.
> >
> > Do we know that the BSR size will always be 4k if it's not a multiple
> > of 64k?  Is it possible that we could get 8k, 16k or 32k or BSRs?
> > If it is possible, what does the user need to be able to do?  Do they
> > just want to map 4k, or might then want to map the whole thing?
>
>
> Hi Paul, I took a look at changing the driver to reject a request for
> mapping more than a single 4k page, however the only indication we get
> of the requested size in the mmap function is the vma size, and this
> is always one page at minimum.  So, it's not possible to determine if
> the user wants one 4k page or more.  As I noted in my first response,
> there is only one case where this is even possible and I don't think
> it is a significant concern.
>
> I did notice that I left out the check to see if the user is trying to
> map more than the device length, so I fixed that.  Here's the revised
> patch.

Alright, I've reworked this now so that if we get one of these cases
where there's a bsr that's > 4k and < 64k on a 64k kernel we'll only
advertise that it is a 4k BSR to userspace.  I think this is the best
solution since user programs are only supposed to look at sysfs to
determine how much can be mapped, and libbsr does this as well.

Please consider for 2.6.31 as a fix, thanks.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-06-26 14:37:26 +10:00
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accessibility
acpi Merge branch 'bjorn-notify' into release 2009-06-24 01:22:20 -04:00
amba
ata libata: don't set IORDY for reset 2009-06-23 01:54:30 -04:00
atm
auxdisplay
base
block
bluetooth
cdrom
char powerpc/BSR: Fix BSR to allow mmap of small BSR on 64k kernel 2009-06-26 14:37:26 +10:00
clocksource
connector
cpufreq
cpuidle
crypto
dca
dio
dma DMA: txx9dmac: use dma_unmap_single if DMA_COMPL_{SRC,DEST}_UNMAP_SINGLE set 2009-06-24 18:34:40 +01:00
edac
eisa
firewire Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 2009-06-22 21:29:52 -07:00
firmware
gpio gpio: driver for PrimeCell PL061 GPIO controller 2009-06-19 16:46:03 -07:00
gpu Merge branch 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2009-06-25 17:04:37 -07:00
hid
hwmon
i2c i2c: fix build bug in i2c-designware.c 2009-06-25 11:22:12 -07:00
ide ide cs5520: Initialize second port's interrupt number. 2009-06-24 02:36:17 -07:00
idle
ieee1394 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 2009-06-22 21:29:52 -07:00
ieee802154
infiniband Merge branches 'ehca', 'misc', 'mlx4', 'mthca' and 'nes' into for-linus 2009-06-23 10:38:47 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2009-06-20 10:17:02 -07:00
isdn
leds
lguest
macintosh powerpc/pmac: Fix DMA ops for MacIO devices 2009-06-26 14:37:25 +10:00
mca
md dm mpath: change to be request based 2009-06-22 10:12:37 +01:00
media V4L/DVB (12131): BUGFIX: An incorrect Carrier Recovery Loop optimization table was being 2009-06-23 03:29:57 -03:00
memstick
message fusion: mptsas, fix lock imbalance 2009-06-22 08:54:14 -05:00
mfd [WATCHDOG] twl4030 watchdog driver 2009-06-20 18:39:43 +00:00
misc
mmc sdhci: remove needless double parenthesis 2009-06-21 21:01:00 +02:00
mtd Merge git://git.infradead.org/mtd-2.6 2009-06-22 16:56:22 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6 2009-06-24 10:01:12 -07:00
nubus
of
oprofile
parisc
parport parport_pc: set properly the dma_mask for parport_pc device 2009-06-22 11:29:00 -07:00
pci Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2009-06-24 10:17:07 -07:00
pcmcia
platform asus-laptop: remove EXPERIMENTAL dependency 2009-06-24 01:34:00 -04:00
pnp Merge branches 'acerhdf', 'acpi-pci-bind', 'bjorn-pci-root', 'bugzilla-12904', 'bugzilla-13121', 'bugzilla-13396', 'bugzilla-13533', 'bugzilla-13612', 'c3_lock', 'hid-cleanups', 'misc-2.6.31', 'pdc-leak-fix', 'pnpacpi', 'power_nocheck', 'thinkpad_acpi', 'video' and 'wmi' into release 2009-06-24 01:19:50 -04:00
power
pps
ps3
rapidio
regulator
rtc rtc: make rtc_update_irq callable with irqs enabled 2009-06-19 16:46:05 -07:00
s390 [S390] dasd: fix refcounting in dasd_change_state 2009-06-22 12:08:23 +02:00
sbus
scsi [SCSI] scsi_transport_fc: replace BUS_ID_SIZE by fixed count 2009-06-21 12:11:43 -05:00
serial pci: use pci_ioremap_bar() in drivers/serial 2009-06-24 09:55:50 -07:00
sh
sn
spi spi_mpc8xxx: s/83xx/8xxx/g 2009-06-19 16:46:05 -07:00
ssb
staging Staging: octeon-ethernet: Fix race freeing transmit buffers. 2009-06-24 18:34:41 +01:00
tc
telephony
thermal
uio
usb usb_serial: Fix oops when unexisting usb serial device is opened. 2009-06-25 11:24:26 -07:00
uwb
video nvidiafb: fix boot-time printk string 2009-06-23 12:50:05 -07:00
virtio
vlynq
w1 Merge git://git.infradead.org/battery-2.6 2009-06-24 14:35:57 -07:00
watchdog [WATCHDOG] wdt_pci.c: remove #ifdef CONFIG_WDT_501_PCI 2009-06-23 07:13:52 +00:00
xen
zorro
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