Commit Graph

268 Commits

Author SHA1 Message Date
Mike Frysinger
39c999697b Blackfin: bf561: rewrite SICA_xxx to just SIC_xxx
This matches all the other Blackfin ports and keep us from having to write
bf561-specific code in many places.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-10-22 16:30:02 -04:00
Sonic Zhang
99a5b2878b Blackfin: add new cacheflush syscall
Flushing caches sometimes requires anomaly workarounds which require
supervisor-only insns.  Normally we don't need to flush caches from
userspace so this isn't a problem, but when gcc generates trampolines
on the stack, we do.

So add a new syscall for gcc to use modeled after the mips version.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-10-22 03:48:59 -04:00
Michael Hennerich
bedeea6e3b Blackfin: SIC: fix off-by-one error in loop
Make sure we include EMAC_SYSTAT when showing errors.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-10-22 03:48:57 -04:00
Barry Song
33ded95b1c Blackfin: initial preempt support while returning from interrupt
Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-10-22 03:48:55 -04:00
David Howells
3b139cdb37 Blackfin: Rename IRQ flags handling functions
Rename h/w IRQ flags handling functions to be in line with what is expected for
the irq renaming patch.  This renames local_*_hw() to hard_local_*() using the
following perl command:

	perl -pi -e 's/local_irq_(restore|enable|disable)_hw/hard_local_irq_\1/ or s/local_irq_save_hw([_a-z]*)[(]flags[)]/flags = hard_local_irq_save\1()/' `find arch/blackfin/ -name "*.[ch]"`

and then fixing up asm/irqflags.h manually.

Additionally, arch/hard_local_save_flags() and arch/hard_local_irq_save() both
return the flags rather than passing it through the argument list.

Signed-off-by: David Howells <dhowells@redhat.com>
2010-10-07 14:08:52 +01:00
Mike Frysinger
f3411b16c7 Blackfin: wire up new fanotify/prlimit64 syscalls
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-08-23 04:24:09 -04:00
Michael Hennerich
f619ddd4fe Blackfin: dpmc: punt unnecessary RTC_ISTAT clearing
The RTC ISTAT bits do not affect wakeups, and the RTC driver already
takes care of clearing this MMR when necessary.  So drop the useless
clearing in the core Blackfin power code.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-08-06 12:55:57 -04:00
Michael Hennerich
d1401e1dc2 Blackfin: fix DMA/cache bug when resuming from suspend to RAM
The dma_memcpy() function takes care of flushing different caches for us.
Normally this is what we want, but when resuming from mem, we don't yet
have caches enabled.  If these functions happen to be placed into L1 mem
(which is what we're trying to relocate), then things aren't going to
work.  So define a non-cache dma_memcpy() variant to utilize in situations
like this.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-08-06 12:55:50 -04:00
Mike Frysinger
74181295fb Blackfin: allow cache funcs to be in L1 for IFLUSH Anomaly 05000491
Anomaly 05000491 says that IFLUSH cannot have certain types of memory
stalls triggered before it has completed in order to function correctly.
One such condition is that it be in L1 instruction.  So add a config
option to move it there, default it to on, and throw up a warning when
it is turned off and this anomaly exists.

Since the anomaly should be worked around, we can drop the older method
of calling IFLUSH multiple times.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
2010-08-06 12:55:47 -04:00
Mike Frysinger
5369fba136 Blackfin: merge anomalies 475 and 220 to follow official lists
Design found that these anomalies had the same root issue, so they've
merged 475 into 220.  We need to do the same to update to the latest
anomaly sheets.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-08-06 12:55:46 -04:00
Mike Frysinger
1ed181f248 Blackfin: move MPU anomaly check to common location
Keep all anomaly/arch checks in one place to keep logic simple.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-08-06 12:55:45 -04:00
Joe Perches
db52ecc295 Blackfin: SMP: fix continuation lines
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-05-22 14:19:15 -04:00
Mike Frysinger
80fcdb9593 Blackfin: SIC: cut down on IAR MMR reads a bit
Tweak the for loops that operate on the SIC IAR system MMRs to avoid
re-reading them multiple times in a row.  System MMRs are a little
slower to access, so avoid the penalty when possible.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-05-22 14:19:09 -04:00
Michael Hennerich
bb84dbf69b Blackfin: punt Blackfin-specific GPIO wakeup API
This patch removes a custom GPIO wakeup API which allowed GPIOs to act
as wakeup sources, which are not configured as Interrupts.
This API is a leftover from the time before irq_wake was established.
From now on people must use enable_irq_wake(GPIO_IRQx) and the GPIO in
question needs to be configured as Interrupt.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-05-21 09:40:16 -04:00
Tejun Heo
5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking 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>
2010-03-30 22:02:32 +09:00
Graf Yang
7998a8787a Blackfin: scale calibration when cpu freq changes
Need to make sure we update the loops_per_jiffy values when we start
changing the core clock.

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:53 -05:00
Robin Getz
2943bff69e Blackfin: fix anomaly 283 handling with exact hardware error
The exact hardware error handling code was added before the workaround
for anomaly 283 which caused the anomaly to be triggered in some cases
(an infinite core stall).  So re-order the code to avoid this.

Reported-by: Andrew Rook <andrew.rook@speakerbus.co.uk>
Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:53 -05:00
Michael Hennerich
ae4a8c1903 Blackfin: don't support keypad wakeup from hibernate
The on-chip keypad peripheral requires different registers to be setup
depending on the standby type (standby vs hibernation).  However, since
the power management framework doesn't differentiate between these types,
the driver doesn't know which registers to program and subsequently it
avoids doing so.

Always enabling the keyboard wakeup source causes misbehavior when the
pins are not assigned to the keypad.  If they happen to drive a certain
level, they'll trigger a wake up event which is not wanted.  So until
the aforementioned issue can be sorted out, drop support for the
wakeup source completely.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:53 -05:00
Michael Hennerich
aec59c9113 Blackfin: add support for the on-chip MAC status interrupts
This patch provides infrastructure for MAC Wake-On-Lan and PHYINT use in
phylib.  New Interrupts added:

IRQ_MAC_PHYINT   /* PHY_INT Interrupt */
IRQ_MAC_MMCINT   /* MMC Counter Interrupt */
IRQ_MAC_RXFSINT  /* RX Frame-Status Interrupt */
IRQ_MAC_TXFSINT  /* TX Frame-Status Interrupt */
IRQ_MAC_WAKEDET  /* Wake-Up Interrupt */
IRQ_MAC_RXDMAERR /* RX DMA Direction Error Interrupt */
IRQ_MAC_TXDMAERR /* TX DMA Direction Error Interrupt */
IRQ_MAC_STMDONE  /* Station Mgt. Transfer Done Interrupt */

On BF537/6 the implementation is not straight forward since there are now
two chained chained_handlers.  A cleaner approach would have been to add
latter IRQs to the demux of IRQ_GENERIC_ERROR.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:52 -05:00
Mike Frysinger
9e228ee9ea Blackfin: check for bad syscalls after tracing it
We want to report all system calls (even invalid ones) to the tracing
layers, so check the NR only after we've notified.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:51 -05:00
Mike Frysinger
600482c13d Blackfin: fix single stepping over system calls
On Blackfin systems, the hardware single step exception triggers before
the system call exception, so we need to save this info to process it
later on.  Otherwise, single stepping in userspace misses a few insns
right after the system call.

This is based a bit on the SuperH code added in commit 4b505db9c4.

Reported-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:51 -05:00
Mike Frysinger
e8f263dfd3 Blackfin: initial tracehook support
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:51 -05:00
Graf Yang
718340f629 Blackfin: rewrite resync_core_{i,d}cache() SMP logic to avoid per_cpu data
This functions are implicitly called by core functions like cpu_relax(),
and since those functions may be called early on before common code has
initialized the per-cpu data area, we need to tweak the stats gathering.
Now the statistics are maintained in common bss which makes these funcs
safe to use as soon as the C runtime env is setup.

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:50 -05:00
Graf Yang
6c2b7072a7 Blackfin: add support for cpufreq on SMP systems
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:50 -05:00
Graf Yang
60ffdb3654 Blackfin: implement nmi_watchdog for SMP on BF561
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:49 -05:00
Michael Hennerich
f3dec78333 Blackfin: increase NR_IRQS beyond NR on-chip IRQs
This makes room for off-chip IRQ controllers.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:49 -05:00
Yi Li
441504df6b Blackfin: add support for irqflags tracing
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:49 -05:00
Barry Song
d86bfb1600 Blackfin: initial XIP support
Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:48 -05:00
Barry Song
aad16f3228 Blackfin: fix initial stack pointer setup
During very early init, the stack pointer is given a slightly incorrect
value (&init_thread_union).  The value is later adjusted to the right one
during early init (&init_thread_union + THREAD_SIZE), but it is used a few
times in between.  While the few functions used don't actually put things
onto the stack (due to optimization), it's best if we simply use the right
value from the start.

Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:48 -05:00
Yi Li
cb191718fc Blackfin: try to simplify interrupt ifdef ugliness
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:48 -05:00
Graf Yang
0b39db28b9 Blackfin: SMP: add PM/CPU hotplug support
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:48 -05:00
Yi Li
0d152c27e3 Blackfin: SMP: make core timers per-cpu clock events for HRT
SMP systems require per-cpu local clock event devices in order to enable
HRT support.  One a BF561, we can use local core timer for this purpose.
Originally, there was one global core-timer clock event device set up for
core A.

To accomplish this feat, we need to split the gptimer0/core timer logic
so that each is a standalone clock event.  There is no requirement that
we only have one clock event source anyways.  Once we have this, we just
define per-cpu clock event devices for each local core timer.

Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:48 -05:00
Sonic Zhang
0325f25a91 Blackfin: SMP: add support for IRQ affinity
Now that the Blackfin IRQ controller supports this, drivers get the normal
functionality of controlling which CPU to bind IRQs to.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:47 -05:00
Michael Hennerich
15435a2a55 Blackfin: pull in asm/bfin_can.h for interrupt masks
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:46 -05:00
Mike Frysinger
360adee8a5 Blackfin: wire up the various memory related syscalls
These all just go to the stub syscall at the moment, so this is largely
future proofing.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:46 -05:00
Yi Li
c9784ebb23 Blackfin: flush caches on SMP when one core calls another via IPI
Sometimes a SMP system will randomly panic at boot.  This is due to caches
being out of sync when one core tries to signal the other.  So when one
core calls another via IPI, flush the data caches.

Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:45 -05:00
Tejun Heo
32032df6c2 Merge branch 'master' into percpu
Conflicts:
	arch/powerpc/platforms/pseries/hvCall.S
	include/linux/percpu.h
2010-01-05 09:17:33 +09:00
Barry Song
d1be2e485b Blackfin: add support for TIF_NOTIFY_RESUME
Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-12-15 00:16:52 -05:00
Mike Frysinger
7eb87fd3f1 Blackfin: BF537: push down error masks to avoid namespace pollution
The error masks are only needed in the BF537 demux error code, so instead
of needing all the short peripheral defines in global space, push these
masks into the one file where they are actually needed.  This fixes a
bunch of define collisions with common code (can/serial/etc...).

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Barry Song <barry.song@analog.com>
2009-12-15 00:16:11 -05:00
Yi Li
578d36f5e1 Blackfin: SMP: don't start up core b until its state has been completely onlined
When testing PREEMPT_RT kernel on BF561-EZKit, the kernel blocks while
booting.  When the kernel initializes the ethernet driver, it sleeps and
never wakes up.

The issue happens when the kernel waits for a timer for Core B to timeout
(the timers are per-cpu based: static DEFINE_PER_CPU(struct tvec_base *,
tvec_bases) = &boot_tvec_bases).

However, the ksoftirqd thread for Core B (note, the ksoftirqd thread is
also per-cpu based) cannot work properly, and the timers for Core B never
times out.

When ksoftirqd() for the first time runs on core B, it is possible core A
is still initializing core B (see smp_init() -> cpu_up() -> __cpu_up()).
So the "cpu_is_offline()" check may return true and ksoftirqd moves to
"wait_to_die".

So delay the core b start up until the per-cpu timers have been set up
fully.

Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-12-15 00:16:09 -05:00
Mike Frysinger
761ec44add Blackfin: pull in asm/dpmc.h for power defines
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-12-15 00:14:50 -05:00
Michael Hennerich
621dd24743 Blackfin: bf538: add support for extended GPIO banks
The GPIOs on ports C/D/E on the BF538/BF539 do not behave the same way as
the other ports on the part and the same way as all other Blackfin parts.
The MMRs are programmed slightly different and they cannot be used to
generate interrupts or wakeup a sleeping system.  Since these guys don't
fit into the existing code, create a simple gpiolib driver for them.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-12-15 00:14:05 -05:00
Michael Hennerich
d887a1ce28 Blackfin: cpufreq: use a constant latency
PLL_LOCKCNT applies only to the PLL programming sequence which does not
apply to core and system clock dividers.  Writes to PLL_DIV to change the
CSEL/SSEL dividers take effect immediately.

There is still overhead in software in writing the new dividers, so just
use a value of 50us as this should be good enough.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-12-15 00:14:00 -05:00
Al Viro
f8b7256096 Unify sys_mmap*
New helper - sys_mmap_pgoff(); switch syscalls to using it.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-11 06:44:29 -05:00
David S. Miller
ff9c38bba3 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	net/mac80211/ht.c
2009-12-01 22:13:38 -08:00
Roel Kluin
05bad36ce7 Blackfin: fix memset in smp_send_reschedule() and -stop()
To set zeroes the sizeof the struct should be used rather
than sizeof the pointer, kzalloc does that.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-11-25 02:35:45 -05:00
Mike Frysinger
a2ca78cee1 Blackfin: check for anomaly 05000475
Parts that have on-chip L2 SRAM cannot safely utilize writeback caching
mode, so reject any attempts to use it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-11-25 02:35:41 -05:00
David S. Miller
3505d1a9fd Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/sfc/sfe4001.c
	drivers/net/wireless/libertas/cmd.c
	drivers/staging/Kconfig
	drivers/staging/Makefile
	drivers/staging/rtl8187se/Kconfig
	drivers/staging/rtl8192e/Kconfig
2009-11-18 22:19:03 -08:00
Rusty Russell
dd17c8f729 percpu: remove per_cpu__ prefix.
Now that the return from alloc_percpu is compatible with the address
of per-cpu vars, it makes sense to hand around the address of per-cpu
variables.  To make this sane, we remove the per_cpu__ prefix we used
created to stop people accidentally using these vars directly.

Now we have sparse, we can use that (next patch).

tj: * Updated to convert stuff which were missed by or added after the
      original patch.

    * Kill per_cpu_var() macro.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
2009-10-29 22:34:15 +09:00
Arnaldo Carvalho de Melo
a2e2725541 net: Introduce recvmmsg socket syscall
Meaning receive multiple messages, reducing the number of syscalls and
net stack entry/exit operations.

Next patches will introduce mechanisms where protocols that want to
optimize this operation will provide an unlocked_recvmsg operation.

This takes into account comments made by:

. Paul Moore: sock_recvmsg is called only for the first datagram,
  sock_recvmsg_nosec is used for the rest.

. Caitlin Bestler: recvmmsg now has a struct timespec timeout, that
  works in the same fashion as the ppoll one.

  If the underlying protocol returns a datagram with MSG_OOB set, this
  will make recvmmsg return right away with as many datagrams (+ the OOB
  one) it has received so far.

. Rémi Denis-Courmont & Steven Whitehouse: If we receive N < vlen
  datagrams and then recvmsg returns an error, recvmmsg will return
  the successfully received datagrams, store the error and return it
  in the next call.

This paves the way for a subsequent optimization, sk_prot->unlocked_recvmsg,
where we will be able to acquire the lock only at batch start and end, not at
every underlying recvmsg call.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-12 23:40:10 -07:00