On Fri, 2007-08-17 at 11:56 -0400, Josef Sipek wrote: > On Thu, Aug 16, 2007 at 09:45:34AM +0200, Peter Zijlstra wrote:
> > Index: linux-2.6/fs/ext2/super.c
> > ===================================================================
> > --- linux-2.6.orig/fs/ext2/super.c
> > +++ linux-2.6/fs/ext2/super.c
> > @@ -725,6 +725,7 @@ static int ext2_fill_super(struct super_
> > int db_count;
> > int i, j;
> > __le32 features;
> > + int err;
> >
> > sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
> > if (!sbi)
> > @@ -996,12 +997,16 @@ static int ext2_fill_super(struct super_
> > sbi->s_rsv_window_head.rsv_goal_size = 0;
> > ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
> >
> > - percpu_counter_init(&sbi->s_freeblocks_counter,
> > + err = percpu_counter_init(&sbi->s_freeblocks_counter,
> > ext2_count_free_blocks(sb));
> > - percpu_counter_init(&sbi->s_freeinodes_counter,
> > + err |= percpu_counter_init(&sbi->s_freeinodes_counter,
> > ext2_count_free_inodes(sb));
> > - percpu_counter_init(&sbi->s_dirs_counter,
> > + err |= percpu_counter_init(&sbi->s_dirs_counter,
> > ext2_count_dirs(sb));
> > + if (err) {
> > + printk(KERN_ERR "EXT2-fs: insufficient memory\n");
> > + goto failed_mount3;
> > + }
>
> Can percpu_counter_init fail with only one error code? If not, the error
> code potentially used in future at failed_mount3 could be nonsensical
> because of the bitwise or-ing.
The actual value of err is irrelevant, it is not used after this not
zero check.
But how about this:
---
Subject: lib: percpu_counter_init error handling
alloc_percpu can fail, propagate that error.
Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]>
---
fs/ext2/super.c | 15 ++++++++++++---
fs/ext3/super.c | 21 +++++++++++++++------
fs/ext4/super.c | 21 +++++++++++++++------
include/linux/percpu_counter.h | 5 +++--
lib/percpu_counter.c | 8 +++++++-
5 files changed, 52 insertions(+), 18 deletions(-)
Index: linux-2.6/fs/ext2/super.c
===================================================================
--- linux-2.6.orig/fs/ext2/super.c
+++ linux-2.6/fs/ext2/super.c
@@ -725,6 +725,7 @@ static int ext2_fill_super(struct super_
int db_count;
int i, j;
__le32 features;
+ int err;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
@@ -996,12 +997,20 @@ static int ext2_fill_super(struct super_
sbi->s_rsv_window_head.rsv_goal_size = 0;
ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
- percpu_counter_init(&sbi->s_freeblocks_counter,
+ err = percpu_counter_init(&sbi->s_freeblocks_counter,
ext2_count_free_blocks(sb));
- percpu_counter_init(&sbi->s_freeinodes_counter,
+ if (!err) {
+ err = percpu_counter_init(&sbi->s_freeinodes_counter,
ext2_count_free_inodes(sb));
- percpu_counter_init(&sbi->s_dirs_counter,
+ }
+ if (!err) {
+ err = percpu_counter_init(&sbi->s_dirs_counter,
ext2_count_dirs(sb));
+ }
+ if (err) {
+ printk(KERN_ERR "EXT2-fs: insufficient memory\n");
+ goto failed_mount3;
+ }
/*
* set up enough so that it can read an inode
*/
Index: linux-2.6/fs/ext3/super.c
===================================================================
--- linux-2.6.orig/fs/ext3/super.c
+++ linux-2.6/fs/ext3/super.c
@@ -1485,6 +1485,7 @@ static int ext3_fill_super (struct super
int i;
int needs_recovery;
__le32 features;
+ int err;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
@@ -1745,12 +1746,20 @@ static int ext3_fill_super (struct super
get_random_bytes(&sbi->s_next_generation, sizeof(u32));
spin_lock_init(&sbi->s_next_gen_lock);
- percpu_counter_init(&sbi->s_freeblocks_counter,
- ext3_count_free_blocks(sb));
- percpu_counter_init(&sbi->s_freeinodes_counter,
- ext3_count_free_inodes(sb));
- percpu_counter_init(&sbi->s_dirs_counter,
- ext3_count_dirs(sb));
+ err = percpu_counter_init(&sbi->s_freeblocks_counter,
+ ext3_count_free_blocks(sb));
+ if (!err) {
+ err = percpu_counter_init(&sbi->s_freeinodes_counter,
+ ext3_count_free_inodes(sb));
+ }
+ if (!err) {
+ err = percpu_counter_init(&sbi->s_dirs_counter,
+ ext3_count_dirs(sb));
+ }
+ if (err) {
+ printk(KERN_ERR "EXT3-fs: insufficient memory\n");
+ goto failed_mount3;
+ }
/* per fileystem reservation list head & lock */
spin_lock_init(&sbi->s_rsv_window_lock);
Index: linux-2.6/fs/ext4/super.c
===================================================================
--- linux-2.6.orig/fs/ext4/super.c
+++ linux-2.6/fs/ext4/super.c
@@ -1576,6 +1576,7 @@ static int ext4_fill_super (struct super
int needs_recovery;
__le32 features;
__u64 blocks_count;
+ int err;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
@@ -1857,12 +1858,20 @@ static int ext4_fill_super (struct super
get_random_bytes(&sbi->s_next_generation, sizeof(u32));
spin_lock_init(&sbi->s_next_gen_lock);
- percpu_counter_init(&sbi->s_freeblocks_counter,
- ext4_count_free_blocks(sb));
- percpu_counter_init(&sbi->s_freeinodes_counter,
- ext4_count_free_inodes(sb));
- percpu_counter_init(&sbi->s_dirs_counter,
- ext4_count_dirs(sb));
+ err = percpu_counter_init(&sbi->s_freeblocks_counter,
+ ext4_count_free_blocks(sb));
+ if (!err) {
+ err = percpu_counter_init(&sbi->s_freeinodes_counter,
+ ext4_count_free_inodes(sb));
+ }
+ if (!err) {
+ err = percpu_counter_init(&sbi->s_dirs_counter,
+ ext4_count_dirs(sb));
+ }
+ if (err) {
+ printk(KERN_ERR "EXT4-fs: insufficient memory\n");
+ goto failed_mount3;
+ }
/* per fileystem reservation list head & lock */
spin_lock_init(&sbi->s_rsv_window_lock);
Index: linux-2.6/include/linux/percpu_counter.h
===================================================================
--- linux-2.6.orig/include/linux/percpu_counter.h
+++ linux-2.6/include/linux/percpu_counter.h
@@ -30,7 +30,7 @@ struct percpu_counter {
#define FBC_BATCH (NR_CPUS*4)
#endif
-void percpu_counter_init(struct percpu_counter *fbc, s64 amount);
+int percpu_counter_init(struct percpu_counter *fbc, s64 amount);
void percpu_counter_destroy(struct percpu_counter *fbc);
void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
@@ -78,9 +78,10 @@ struct percpu_counter {
s64 count;
};
-static inline void percpu_counter_init(struct percpu_counter *fbc, s64 amount)
+static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
{
fbc->count = amount;
+ return 0;
}
static inline void percpu_counter_destroy(struct percpu_counter *fbc)
Index: linux-2.6/lib/percpu_counter.c
===================================================================
--- linux-2.6.orig/lib/percpu_counter.c
+++ linux-2.6/lib/percpu_counter.c
@@ -68,21 +68,27 @@ s64 __percpu_counter_sum(struct percpu_c
}
EXPORT_SYMBOL(__percpu_counter_sum);
-void percpu_counter_init(struct percpu_counter *fbc, s64 amount)
+int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
{
spin_lock_init(&fbc->lock);
fbc->count = amount;
fbc->counters = alloc_percpu(s32);
+ if (!fbc->counters)
+ return -ENOMEM;
#ifdef CONFIG_HOTPLUG_CPU
mutex_lock(&percpu_counters_lock);
list_add(&fbc->list, &percpu_counters);
mutex_unlock(&percpu_counters_lock);
#endif
+ return 0;
}
EXPORT_SYMBOL(percpu_counter_init);
void percpu_counter_destroy(struct percpu_counter *fbc)
{
+ if (!fbc->counters)
+ return;
+
free_percpu(fbc->counters);
#ifdef CONFIG_HOTPLUG_CPU
mutex_lock(&percpu_counters_lock);
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