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| author | Al Viro <viro@zeniv.linux.org.uk> | 2010-05-26 15:13:55 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2010-05-27 22:03:07 -0400 |
| commit | d7065da038227a4d09a244e6014e0186a6bd21d0 (patch) | |
| tree | 0b3b30a6ec59aa03e5fb7084eed31f2a5dfc9686 /include | |
| parent | 176306f59ac7a35369cbba87aff13e14c5916074 (diff) | |
| download | linux-3.10-d7065da038227a4d09a244e6014e0186a6bd21d0.tar.gz linux-3.10-d7065da038227a4d09a244e6014e0186a6bd21d0.tar.bz2 linux-3.10-d7065da038227a4d09a244e6014e0186a6bd21d0.zip | |
get rid of the magic around f_count in aio
__aio_put_req() plays sick games with file refcount. What
it wants is fput() from atomic context; it's almost always
done with f_count > 1, so they only have to deal with delayed
work in rare cases when their reference happens to be the
last one. Current code decrements f_count and if it hasn't
hit 0, everything is fine. Otherwise it keeps a pointer
to struct file (with zero f_count!) around and has delayed
work do __fput() on it.
Better way to do it: use atomic_long_add_unless( , -1, 1)
instead of !atomic_long_dec_and_test(). IOW, decrement it
only if it's not the last reference, leave refcount alone
if it was. And use normal fput() in delayed work.
I've made that atomic_long_add_unless call a new helper -
fput_atomic(). Drops a reference to file if it's safe to
do in atomic (i.e. if that's not the last one), tells if
it had been able to do that. aio.c converted to it, __fput()
use is gone. req->ki_file *always* contributes to refcount
now. And __fput() became static.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/file.h | 1 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 |
2 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/file.h b/include/linux/file.h index 5555508fd51..b1e12970f61 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -11,7 +11,6 @@ struct file; -extern void __fput(struct file *); extern void fput(struct file *); extern void drop_file_write_access(struct file *file); diff --git a/include/linux/fs.h b/include/linux/fs.h index 85e823adcd4..3d9ed830240 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -954,6 +954,7 @@ extern spinlock_t files_lock; #define file_list_unlock() spin_unlock(&files_lock); #define get_file(x) atomic_long_inc(&(x)->f_count) +#define fput_atomic(x) atomic_long_add_unless(&(x)->f_count, -1, 1) #define file_count(x) atomic_long_read(&(x)->f_count) #ifdef CONFIG_DEBUG_WRITECOUNT |