The patch titled
lguest: remove usage and export of __put_task_struct()
has been added to the -mm tree. Its filename is
lguest-the-host-code-remove-usage-and-export-of-__put_task_struct.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: lguest: remove usage and export of __put_task_struct()
From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
lguest takes a reference count of tasks for two reasons. The first is
bogus: the /dev/lguest close callback will be called before the task is
destroyed anyway, so no need to take a reference on open.
The second is code to defer waking up tasks for inter-guest I/O, but the
current lguest drivers are too simplistic to benefit (only batched
hypercalls will see an effect, and it's likely that lguests' entire I/O
model will be replaced with virtio and ringbuffers anyway).
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/lguest/hypercalls.c | 1 -
drivers/lguest/io.c | 18 +-----------------
drivers/lguest/lg.h | 1 -
drivers/lguest/lguest_user.c | 2 --
kernel/fork.c | 1 -
5 files changed, 1 insertion(+), 22 deletions(-)
diff -puN drivers/lguest/hypercalls.c~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct drivers/lguest/hypercalls.c
--- a/drivers/lguest/hypercalls.c~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct
+++ a/drivers/lguest/hypercalls.c
@@ -189,5 +189,4 @@ void do_hypercalls(struct lguest *lg)
do_hcall(lg, lg->regs);
clear_hcall(lg);
}
- set_wakeup_process(lg, NULL);
}
diff -puN drivers/lguest/io.c~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct drivers/lguest/io.c
--- a/drivers/lguest/io.c~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct
+++ a/drivers/lguest/io.c
@@ -296,7 +296,7 @@ static int dma_transfer(struct lguest *s
/* Do this last so dst doesn't simply sleep on lock. */
set_bit(dst->interrupt, dstlg->irqs_pending);
- set_wakeup_process(srclg, dstlg->tsk);
+ wake_up_process(dstlg->tsk);
return i == dst->num_dmas;
fail:
@@ -333,7 +333,6 @@ again:
/* Give any recipients one chance to restock. */
up_read(¤t->mm->mmap_sem);
mutex_unlock(&lguest_lock);
- set_wakeup_process(lg, NULL);
empty++;
goto again;
}
@@ -362,21 +361,6 @@ void release_all_dma(struct lguest *lg)
up_read(&lg->mm->mmap_sem);
}
-/* We cache one process to wakeup: helps for batching & wakes outside locks. */
-void set_wakeup_process(struct lguest *lg, struct task_struct *p)
-{
- if (p == lg->wake)
- return;
-
- if (lg->wake) {
- wake_up_process(lg->wake);
- put_task_struct(lg->wake);
- }
- lg->wake = p;
- if (lg->wake)
- get_task_struct(lg->wake);
-}
-
/* Userspace wants a dma buffer from this guest. */
unsigned long get_dma_buffer(struct lguest *lg,
unsigned long ukey, unsigned long *interrupt)
diff -puN drivers/lguest/lg.h~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct drivers/lguest/lg.h
--- a/drivers/lguest/lg.h~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct
+++ a/drivers/lguest/lg.h
@@ -240,7 +240,6 @@ void send_dma(struct lguest *info, unsig
void release_all_dma(struct lguest *lg);
unsigned long get_dma_buffer(struct lguest *lg, unsigned long key,
unsigned long *interrupt);
-void set_wakeup_process(struct lguest *lg, struct task_struct *p);
/* hypercalls.c: */
void do_hypercalls(struct lguest *lg);
diff -puN drivers/lguest/lguest_user.c~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct drivers/lguest/lguest_user.c
--- a/drivers/lguest/lguest_user.c~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct
+++ a/drivers/lguest/lguest_user.c
@@ -141,7 +141,6 @@ static int initialize(struct file *file,
setup_guest_gdt(lg);
init_clockdev(lg);
lg->tsk = current;
- get_task_struct(lg->tsk);
lg->mm = get_task_mm(lg->tsk);
init_waitqueue_head(&lg->break_wq);
lg->last_pages = NULL;
@@ -205,7 +204,6 @@ static int close(struct inode *inode, st
hrtimer_cancel(&lg->hrt);
release_all_dma(lg);
free_guest_pagetable(lg);
- put_task_struct(lg->tsk);
mmput(lg->mm);
if (!IS_ERR(lg->dead))
kfree(lg->dead);
diff -puN kernel/fork.c~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct kernel/fork.c
--- a/kernel/fork.c~lguest-the-host-code-remove-usage-and-export-of-__put_task_struct
+++ a/kernel/fork.c
@@ -127,7 +127,6 @@ void __put_task_struct(struct task_struc
if (!profile_handoff_task(tsk))
free_task(tsk);
}
-EXPORT_SYMBOL_GPL(__put_task_struct);
void __init fork_init(unsigned long mempages)
{
_
Patches currently in -mm which might be from rusty@xxxxxxxxxxxxxxx are
git-kbuild.patch
paravirt-helper-to-disable-all-io-space-fix.patch
mm-clean-up-and-kernelify-shrinker-registration.patch
mm-clean-up-and-kernelify-shrinker-registration-vs-git-nfs.patch
use-menuconfig-objects-ii-module-menu.patch
fix-stop_machine_run-problem-with-naughty-real-time-process.patch
cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process.patch
modules-remove-modlist_lock.patch
permit-mempool_freenull.patch
lguest-export-symbols-for-lguest-as-a-module.patch
lguest-the-guest-code.patch
lguest-the-host-code.patch
lguest-the-host-code-lguest-vs-clockevents-fix-resume-logic.patch
lguest-the-host-code-remove-usage-and-export-of-__put_task_struct.patch
lguest-the-asm-offsets.patch
lguest-the-makefile-and-kconfig.patch
lguest-the-console-driver.patch
lguest-the-net-driver.patch
lguest-the-block-driver.patch
lguest-the-documentation-example-launcher.patch
readahead-introduce-pg_readahead.patch
readahead-add-look-ahead-support-to-__do_page_cache_readahead.patch
readahead-min_ra_pages-max_ra_pages-macros.patch
readahead-data-structure-and-routines.patch
readahead-on-demand-readahead-logic.patch
readahead-convert-filemap-invocations.patch
readahead-convert-splice-invocations.patch
readahead-convert-ext3-ext4-invocations.patch
readahead-remove-the-old-algorithm.patch
readahead-move-synchronous-readahead-call-out-of-splice-loop.patch
readahead-pass-real-splice-size.patch
mm-share-pg_readahead-and-pg_reclaim.patch
readahead-split-ondemand-readahead-interface-into-two-functions.patch
readahead-sanify-file_ra_state-names.patch
define-new-percpu-interface-for-shared-data-version-4.patch
use-the-new-percpu-interface-for-shared-data-version-4.patch
mm-clean-up-and-kernelify-shrinker-registration-reiser4.patch
-
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