summaryrefslogtreecommitdiff
path: root/drivers/net/wireless/b43/dma.c
AgeCommit message (Collapse)Author
2013-05-10Merge branch 'master' of ↵John W. Linville
git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless into for-davem
2013-05-08B43: Handle DMA RX descriptor underrunThommy Jakobsson
Add handling of rx descriptor underflow. This fixes a fault that could happen on slow machines, where data is received faster than the CPU can handle. In such a case the device will use up all rx descriptors and refuse to send any more data before confirming that it is ok. This patch enables necessary interrupt to discover such a situation and will handle them by dropping everything in the ring buffer. Reviewed-by: Michael Buesch <m@bues.ch> Signed-off-by: Thommy Jakobsson <thommyj@gmail.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2013-04-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: net/mac80211/sta_info.c net/wireless/core.h Two minor conflicts in wireless. Overlapping additions of extern declarations in net/wireless/core.h and a bug fix overlapping with the addition of a boolean parameter to __ieee80211_key_free(). Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-27b43: A fix for DMA transmission sequence errorsIestyn C. Elfick
Intermittently, b43 will report "Out of order TX status report on DMA ring". When this happens, the driver must be reset before communication can resume. The cause of the problem is believed to be an error in the closed-source firmware; however, all versions of the firmware are affected. This change uses the observation that the expected status is always 2 less than the observed value, and supplies a fake status report to skip one header/data pair. Not all devices suffer from this problem, but it can occur several times per second under heavy load. As each occurence kills the unmodified driver, this patch makes if possible for the affected devices to function. The patch logs only the first instance of the reset operation to prevent spamming the logs. Tested-by: Chris Vine <chris@cvine.freeserve.co.uk> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Cc: Stable <stable@vger.kernel.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2013-03-17drivers:net: dma_alloc_coherent: use __GFP_ZERO instead of memset(, 0)Joe Perches
Reduce the number of calls required to alloc a zeroed block of memory. Trivially reduces overall object size. Other changes around these removals o Neaten call argument alignment o Remove an unnecessary OOM message after dma_alloc_coherent failure o Remove unnecessary gfp_t stack variable Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-12-10b43: fix tx path skb leaksFelix Fietkau
ieee80211_free_txskb() needs to be used instead of dev_kfree_skb_any for tx packets passed to the driver from mac80211 Signed-off-by: Felix Fietkau <nbd@openwrt.org> Cc: stable@vger.kernel.org Signed-off-by: John W. Linville <linville@tuxdriver.com>
2012-05-16b43: use pci_is_pcie() instead of obsolete pci_dev.is_pcieBjorn Helgaas
Use pci_is_pcie() instead of looking at obsolete is_pcie field in struct pci_dev. CC: Stefano Brivio <stefano.brivio@polimi.it> CC: b43-dev@lists.infradead.org CC: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2012-01-03Merge branch 'master' of ↵John W. Linville
git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next into for-davem Conflicts: drivers/net/wireless/b43/dma.c drivers/net/wireless/brcm80211/brcmfmac/dhd_linux.c
2011-12-19net: fix assignment of 0/1 to bool variables.Rusty Russell
DaveM said: Please, this kind of stuff rots forever and not using bool properly drives me crazy. Joe Perches <joe@perches.com> gave me the spatch script: @@ bool b; @@ -b = 0 +b = false @@ bool b; @@ -b = 1 +b = true I merely installed coccinelle, read the documentation and took credit. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-19b43: avoid packet losses in the dma worker code.francesco.gringoli@ing.unibs.it
Following Rafal request, we verified that on "modern" CPUs using one or more workers is equivalent. Here is patch V3 that addresses the packet loss bug in the dma engine using only one worker. ------- This patch addresses a bug in the dma worker code that keeps draining packets even when the hardware queues are full. In such cases packets can not be passed down to the device and are erroneusly dropped by the code. This problem was already discussed here http://www.mail-archive.com/b43-dev@lists.infradead.org/msg01413.html and acknowledged by Michael. Number of hardware queues is now defined in b43.h (B43_QOS_QUEUE_NUM). Acknowledgements to Riccardo Paolillo <riccardo.paolillo@gmail.com> and Michele Orru <michele.orru@hotmail.it> Signed-off-by: Francesco Gringoli <francesco.gringoli@ing.unibs.it> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-09-13Merge branch 'master' of ↵John W. Linville
git://git.infradead.org/users/linville/wireless-next into for-davem
2011-08-29b43: use 8K buffers for 64-bit DMA to workaround hardware bugRafał Miłecki
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-08-29b43: Relax requirement for descriptors to be in the DMA zoneLarry Finger
When 64-bit DMA was first used, there were problems with the BCM4311 (14e4:4311). The problem was "fixed" by using the GFP_DMA flag in the allocation of coherent ring descriptor memory. The original problem is now believed to have been due to bugs in the 64-bit DMA implementation in the rest of the kernel, and that those bugs have been fixed. Accordingly, the requirement for the descriptors to be in the DMA zone is relaxed. Bounce buffers are left in the DMA zone. Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Michael Buesch <m@bues.ch> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-08-29Merge branch 'master' of ↵John W. Linville
git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next into for-davem
2011-08-24b43: fix DMA on some bugged hardwareRafał Miłecki
Some hardware with 64-bit DMA uses lower address word for setting routing (translation) bit. Add workaround for such boards. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-08-22b43: support new RX header, noticed to be used in 598.314+ fwRafał Miłecki
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-08-09b43: read correct register on bcma bus.Hauke Mehrtens
This causes an databus error on a Broadcom SoC using bcma. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-07-25Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits) fs: Merge split strings treewide: fix potentially dangerous trailing ';' in #defined values/expressions uwb: Fix misspelling of neighbourhood in comment net, netfilter: Remove redundant goto in ebt_ulog_packet trivial: don't touch files that are removed in the staging tree lib/vsprintf: replace link to Draft by final RFC number doc: Kconfig: `to be' -> `be' doc: Kconfig: Typo: square -> squared doc: Konfig: Documentation/power/{pm => apm-acpi}.txt drivers/net: static should be at beginning of declaration drivers/media: static should be at beginning of declaration drivers/i2c: static should be at beginning of declaration XTENSA: static should be at beginning of declaration SH: static should be at beginning of declaration MIPS: static should be at beginning of declaration ARM: static should be at beginning of declaration rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_check Update my e-mail address PCIe ASPM: forcedly -> forcibly gma500: push through device driver tree ... Fix up trivial conflicts: - arch/arm/mach-ep93xx/dma-m2p.c (deleted) - drivers/gpio/gpio-ep93xx.c (renamed and context nearby) - drivers/net/r8169.c (just context changes)
2011-07-22b43: bcma: get DMA translation bitsRafał Miłecki
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-07-22ssb: return correct translation bit for 64-bit DMARafał Miłecki
Remove b43's workarounds at the same time. Other users of ssb_dma_translation do not support any 64-bit DMA devices, so they are not affected. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-07-22b43: disable parity check on BCMA devicesRafał Miłecki
Analyze of MMIO dumps from BCM43224, BCM43225, BCM4313 and BCM4331 has shown that wl disables parity check for all that cards. This is required for receiving any packets from the hardware. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-07-08b43: use switches for SSB specific codeRafał Miłecki
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-07-07Update my e-mail addressMichael Büsch
Signed-off-by: Michael Buesch <m@bues.ch> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-07-05b43: Add RX side DMA memory barrierMichael Büsch
This adds a memory barrier to ensure the writes to the ring memory are committed before the DMA ring pointer is updated. We do a similar thing on the TX side already. Signed-off-by: Michael Buesch <m@bues.ch> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-06-01b43: Fix warnings from gcc 4.6.0Larry Finger
gcc 4.6.0 warnings for b43: CC [M] drivers/net/wireless/b43/lo.o drivers/net/wireless/b43/lo.c: In function ‘lo_measure_gain_values’: drivers/net/wireless/b43/lo.c:304:7: warning: variable ‘trsw_rx’ set but not used [-Wunused-but-set-variable] CC [M] drivers/net/wireless/b43/dma.o drivers/net/wireless/b43/dma.c: In function ‘free_all_descbuffers’: drivers/net/wireless/b43/dma.c:760:30: warning: variable ‘desc’ set but not used [-Wunused-but-set-variable] drivers/net/wireless/b43/dma.c: In function ‘b43_dma_handle_txstatus’: drivers/net/wireless/b43/dma.c:1391:30: warning: variable ‘desc’ set but not used [-Wunused-but-set-variable] Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-06-01b43: bus: abstract device structs and irqRafał Miłecki
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-06-01b43: bus: abstract 80211 core infoRafał Miłecki
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-19b43: dma: cache translation (routing bits)Rafał Miłecki
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-16b43: rename b43_wldev's field with ssb_device to sdevRafał Miłecki
We free name "dev" for something generic (like dev abstraction layer). Additionaly code is cleaner now, especially magic dev->dev-dev chains. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-04-04b43: allocate receive buffers big enough for max frame len + offsetJohn W. Linville
Otherwise, skb_put inside of dma_rx can fail... https://bugzilla.kernel.org/show_bug.cgi?id=32042 Signed-off-by: John W. Linville <linville@tuxdriver.com> Acked-by: Larry Finger <Larry.Finger@lwfinger.net> Cc: stable@kernel.org
2010-11-15b43: remove extraneous code in free_ringmemoryJohn W. Linville
This code seems to have been cut-n-pasted from alloc_ringmemory? Anyway, it is useless. Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-06-04b43: replace the ssb_dma API with the generic DMA APIFUJITA Tomonori
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Stefano Brivio <stefano.brivio@polimi.it> Cc: John W. Linville <linville@tuxdriver.com> Acked-by: Michael Buesch <mb@bu3sch.de> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-06-02drivers/net/wireless/b43: Use kmemdupJulia Lawall
Use kmemdup when some other buffer is immediately copied into the allocated region. A simplified version of the semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression from,to,size,flag; statement S; @@ - to = \(kmalloc\|kzalloc\)(size,flag); + to = kmemdup(from,size,flag); if (to==NULL || ...) S - memcpy(to, from, size); // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-02-08b43: remove get_tx_stats() mac80211 opKalle Valo
get_tx_stats() will be removed from mac80211. Compile-tested only. Cc: Stefano Brivio <stefano.brivio@polimi.it> Cc: Michael Buesch <mb@bu3sch.de> Cc: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Kalle Valo <kalle.valo@iki.fi> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-12-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6John W. Linville
Conflicts: drivers/net/wireless/libertas/scan.c
2009-12-29Revert "b43: Enforce DMA descriptor memory constraints"John W. Linville
This reverts commit 9bd568a50c446433038dec2a5186c5c57c3dbd23. That commit is shown to cause allocation failures during initialization on some machines. http://bugzilla.kernel.org/show_bug.cgi?id=14844 Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-12-28b43: Allow PIO mode to be selected at module loadLarry Finger
If userencounter the "Fatal DMA Problem" with a BCM43XX device, and still wish to use b43 as the driver, their only option is to rebuild the kernel with CONFIG_B43_FORCE_PIO. This patch removes this option and allows PIO mode to be selected with a load-time parameter for the module. Note that the configuration variable CONFIG_B43_PIO is also removed. Once the DMA problem with the BCM4312 devices is solved, this patch will likely be reverted. Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Tested-by: John Daiker <daikerjohn@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-23b43: Rewrite DMA Tx status handling sanity checksMichael Buesch
This rewrites the error handling policies in the TX status handler. It tries to be error-tolerant as in "try hard to not crash the machine". It won't recover from errors (that are bugs in the firmware or driver), because that's impossible. However, it will return a more or less useful error message and bail out. It also tries hard to use rate-limited messages to not flood the syslog in case of a failure. Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-18b43: Enforce DMA descriptor memory constraintsMichael Buesch
Enforce all device constraints on the descriptor memory region. There are several constraints on the descriptor memory, as documented in the specification. The current code does not enforce them and/or incorrectly enforces them. Those constraints are: - The address limitations on 30/32bit engines, that also apply to the skbs. - The 4k alignment requirement on 30/32bit engines. - The 8k alignment requirement on 64bit engines. Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-11b43: Rewrite TX bounce buffer handlingMichael Buesch
Do not mess with the original skb, but allocate an independent bouncebuffer. This protects against bad interference with mac80211's assumptions about the skb (which already caused bugs). Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-10-30b43: Fix DMA TX bounce buffer copyingMichael Buesch
b43 allocates a bouncebuffer, if the supplied TX skb is in an invalid memory range for DMA. However, this is broken in that it fails to copy over some metadata to the new skb. This patch fixes three problems: * Failure to adjust the ieee80211_tx_info pointer to the new buffer. This results in a kmemcheck warning. * Failure to copy the skb cb, which contains ieee80211_tx_info, to the new skb. This results in breakage of various TX-status postprocessing (Rate control). * Failure to transfer the queue mapping. This results in the wrong queue being stopped on saturation and can result in queue overflow. Signed-off-by: Michael Buesch <mb@bu3sch.de> Tested-by: Christian Casteyde <casteyde.christian@free.fr> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-09-23b43: Do not use _irqsafe callbacksMichael Buesch
We don't need to call the irqsafe callbacks. Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-09-08b43: Remove DMA/PIO queue locksMichael Buesch
This removes the DMA/PIO queue locks. Locking is handled by wl->mutex now. Signed-off-by: Michael Buesch <mb@bu3sch.de> Tested-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-09-08b43: Use a threaded IRQ handlerMichael Buesch
Use a threaded IRQ handler to allow locking the mutex and sleeping while executing an interrupt. This removes usage of the irq_lock spinlock, but introduces a new hardirq_lock, which is _only_ used for the PCI/SSB lowlevel hard-irq handler. Sleeping busses (SDIO) will use mutex instead. Signed-off-by: Michael Buesch <mb@bu3sch.de> Tested-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-08-20b43: add hardware tkipgregor kowski
This add hardware tkip for b43. Signed-off-by: Gregor Kowski <gregor.kowski@gmail.com> Acked-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-08-04b43: Work around mac80211 race conditionLarry Finger
As shown in http://thread.gmane.org/gmane.linux.kernel.wireless.general/36497, mac80211 has a bug that allows a call to the TX routine after the queues have been stopped. This situation will only occur under extreme stress. Although b43 does not crash when this condition occurs, it does generate a WARN_ON and also logs a queue overrun message. This patch recognizes b43 is not at fault and logs a message only when the most verbose debugging mode is enabled. In the unlikely event that the queue is not stopped when the DMA queue becomes full, then a warning is issued. During testing of this patch with one output stream running repeated tcpperf writes and a second running a flood ping, this routine was entered with the DMA ring stopped about once per hour. The condition where the DMA queue is full but the ring has not been stopped has never been seen by me. Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-06-10b43: Add fw capabilitiesMichael Buesch
Add automagic feature flags, so the firmware can tell the driver about supported features and the driver can switch features on/off as needed. Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de> Tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-16b43: Refresh RX poison on buffer recyclingMichael Buesch
The RX buffer poison needs to be refreshed, if we recycle an RX buffer, because it might be (partially) overwritten by some DMA operations. Cc: stable@kernel.org Cc: Francesco Gringoli <francesco.gringoli@ing.unibs.it> Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-16b43: Poison RX buffersMichael Buesch
This patch adds poisoning and sanity checking to the RX DMA buffers. This is used for protection against buggy hardware/firmware that raises RX interrupts without doing an actual DMA transfer. This mechanism protects against rare "bad packets" (due to uninitialized skb data) and rare kernel crashes due to uninitialized RX headers. The poison is selected to not match on valid frames and to be cheap for checking. The poison check mechanism _might_ trigger incorrectly, if we are voluntarily receiving frames with bad PLCP headers. However, this is nonfatal, because the chance of such a match is basically zero and in case it happens it just results in dropping the packet. Bad-PLCP RX defaults to off, and you should leave it off unless you want to listen to the latest news broadcasted by your microwave oven. This patch also moves the initialization of the RX-header "length" field in front of the mapping of the DMA buffer. The CPU should not touch the buffer after we mapped it. Cc: stable@kernel.org Reported-by: Francesco Gringoli <francesco.gringoli@ing.unibs.it> Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>