Message ID | 8b2369ef-a537-974e-725b-f55d49a646b6@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
On Tue, 19 Sep 2017, Joe Lawrence wrote: > On 09/14/2017 07:09 PM, Mikulas Patocka wrote: > > > > I think this mutex is too heavy - if multiple processes simultaneously > > create a pipe, the mutex would cause performance degradation. > > > > You can call do_proc_dointvec with a custom callback "conv" function > > that does the rounding of the pipe size value. > > Okay, that would consolidate the fiddling with pipe_max_size into a > single place / assignment. > > Implementation wise, are you suggesting something like the following > (work in progress). round_pipe_size() would still be used by > fs/pipe.c::pipe_set_size() so it would need to be visible to both source > files. The proc_do... function would be pipe-max-size specific as it's > basically: > > - proc_douintvec_minmax, but > - without the "max" check > - with an added PAGE_SIZE floor > - PAGE_SIZE increment > > and exported for pipe.c to call. > > Plumbing in the opposite direction (export do_proc_douintvec() and stick > the new conv implementation in fs/pipe.c) might be a little easier, but > seems like the same ick-factor in the end. > > Regards, > > -- Joe Yes. I think this is correct. Reviewed-by: Mikulas Patocka <mpatocka@redhat.com> > -->8-- -->8-- -->8-- -->8-- > > diff --git a/fs/pipe.c b/fs/pipe.c > index 8cbc97d97753..4db3cd2d139c 100644 > --- a/fs/pipe.c > +++ b/fs/pipe.c > @@ -1019,7 +1019,7 @@ static int fifo_open(struct inode *inode, struct > file *filp) > * Currently we rely on the pipe array holding a power-of-2 number > * of pages. Returns 0 on error. > */ > -static inline unsigned int round_pipe_size(unsigned int size) > +unsigned int round_pipe_size(unsigned int size) > { > unsigned long nr_pages; > > @@ -1130,19 +1130,7 @@ static long pipe_set_size(struct pipe_inode_info > *pipe, unsigned long arg) > int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf, > size_t *lenp, loff_t *ppos) > { > - unsigned int rounded_pipe_max_size; > - int ret; > - > - ret = proc_douintvec_minmax(table, write, buf, lenp, ppos); > - if (ret < 0 || !write) > - return ret; > - > - rounded_pipe_max_size = round_pipe_size(pipe_max_size); > - if (rounded_pipe_max_size == 0) > - return -EINVAL; > - > - pipe_max_size = rounded_pipe_max_size; > - return ret; > + return proc_dopipe_max_size(table, write, buf, lenp, ppos); > } > > /* > diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h > index e7497c9dde7f..485cf7a7aa8f 100644 > --- a/include/linux/pipe_fs_i.h > +++ b/include/linux/pipe_fs_i.h > @@ -190,5 +190,6 @@ static inline int pipe_buf_steal(struct > pipe_inode_info *pipe, > struct pipe_inode_info *get_pipe_info(struct file *file); > > int create_pipe_files(struct file **, int); > +unsigned int round_pipe_size(unsigned int size); > > #endif > diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h > index 1d4dba490fb6..ba24ca72800c 100644 > --- a/include/linux/sysctl.h > +++ b/include/linux/sysctl.h > @@ -50,6 +50,9 @@ extern int proc_dointvec_minmax(struct ctl_table *, int, > extern int proc_douintvec_minmax(struct ctl_table *table, int write, > void __user *buffer, size_t *lenp, > loff_t *ppos); > +extern int proc_dopipe_max_size(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, > + loff_t *ppos); > extern int proc_dointvec_jiffies(struct ctl_table *, int, > void __user *, size_t *, loff_t *); > extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int, > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index c976719bf37a..7a2913c5546e 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -67,6 +67,7 @@ > #include <linux/kexec.h> > #include <linux/bpf.h> > #include <linux/mount.h> > +#include <linux/pipe_fs_i.h> > > #include <linux/uaccess.h> > #include <asm/processor.h> > @@ -2631,6 +2632,47 @@ int proc_douintvec_minmax(struct ctl_table > *table, int write, > do_proc_douintvec_minmax_conv, ¶m); > } > > +struct do_proc_dopipe_max_size_conv_param { > + unsigned int *min; > +}; > + > +static int do_proc_dopipe_max_size_conv(unsigned long *lvalp, > + unsigned int *valp, > + int write, void *data) > +{ > + struct do_proc_dopipe_max_size_conv_param *param = data; > + > + if (write) { > + unsigned int val = round_pipe_size(*lvalp); > + > + if (val == 0) > + return -EINVAL; > + > + if (param->min && *param->min > val) > + return -ERANGE; > + > + if (*lvalp > UINT_MAX) > + return -EINVAL; > + > + *valp = val; > + } else { > + unsigned int val = *valp; > + *lvalp = (unsigned long) val; > + } > + > + return 0; > +} > + > +int proc_dopipe_max_size(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + struct do_proc_dopipe_max_size_conv_param param = { > + .min = (unsigned int *) table->extra1, > + }; > + return do_proc_douintvec(table, write, buffer, lenp, ppos, > + do_proc_dopipe_max_size_conv, ¶m); > +} > + > static void validate_coredump_safety(void) > { > #ifdef CONFIG_COREDUMP > @@ -3179,6 +3221,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct > ctl_table *table, int write, > EXPORT_SYMBOL(proc_dointvec_jiffies); > EXPORT_SYMBOL(proc_dointvec_minmax); > EXPORT_SYMBOL_GPL(proc_douintvec_minmax); > +EXPORT_SYMBOL_GPL(proc_dopipe_max_size); > EXPORT_SYMBOL(proc_dointvec_userhz_jiffies); > EXPORT_SYMBOL(proc_dointvec_ms_jiffies); > EXPORT_SYMBOL(proc_dostring); > -- > 1.8.3.1 >
diff --git a/fs/pipe.c b/fs/pipe.c index 8cbc97d97753..4db3cd2d139c 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -1019,7 +1019,7 @@ static int fifo_open(struct inode *inode, struct file *filp) * Currently we rely on the pipe array holding a power-of-2 number * of pages. Returns 0 on error. */ -static inline unsigned int round_pipe_size(unsigned int size) +unsigned int round_pipe_size(unsigned int size) { unsigned long nr_pages; @@ -1130,19 +1130,7 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf, size_t *lenp, loff_t *ppos) { - unsigned int rounded_pipe_max_size; - int ret; - - ret = proc_douintvec_minmax(table, write, buf, lenp, ppos); - if (ret < 0 || !write) - return ret; - - rounded_pipe_max_size = round_pipe_size(pipe_max_size); - if (rounded_pipe_max_size == 0) - return -EINVAL; - - pipe_max_size = rounded_pipe_max_size; - return ret; + return proc_dopipe_max_size(table, write, buf, lenp, ppos); } /* diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index e7497c9dde7f..485cf7a7aa8f 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -190,5 +190,6 @@ static inline int pipe_buf_steal(struct pipe_inode_info *pipe, struct pipe_inode_info *get_pipe_info(struct file *file); int create_pipe_files(struct file **, int); +unsigned int round_pipe_size(unsigned int size); #endif diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 1d4dba490fb6..ba24ca72800c 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -50,6 +50,9 @@ extern int proc_dointvec_minmax(struct ctl_table *, int, extern int proc_douintvec_minmax(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); +extern int proc_dopipe_max_size(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos); extern int proc_dointvec_jiffies(struct ctl_table *, int, void __user *, size_t *, loff_t *); extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int, diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c976719bf37a..7a2913c5546e 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -67,6 +67,7 @@ #include <linux/kexec.h> #include <linux/bpf.h> #include <linux/mount.h> +#include <linux/pipe_fs_i.h> #include <linux/uaccess.h> #include <asm/processor.h> @@ -2631,6 +2632,47 @@ int proc_douintvec_minmax(struct ctl_table *table, int write, do_proc_douintvec_minmax_conv, ¶m); } +struct do_proc_dopipe_max_size_conv_param { + unsigned int *min; +}; + +static int do_proc_dopipe_max_size_conv(unsigned long *lvalp, + unsigned int *valp, + int write, void *data) +{ + struct do_proc_dopipe_max_size_conv_param *param = data; + + if (write) { + unsigned int val = round_pipe_size(*lvalp); + + if (val == 0) + return -EINVAL; + + if (param->min && *param->min > val) + return -ERANGE; + + if (*lvalp > UINT_MAX) + return -EINVAL; + + *valp = val; + } else { + unsigned int val = *valp; + *lvalp = (unsigned long) val; + } + + return 0; +} + +int proc_dopipe_max_size(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct do_proc_dopipe_max_size_conv_param param = { + .min = (unsigned int *) table->extra1, + }; + return do_proc_douintvec(table, write, buffer, lenp, ppos, + do_proc_dopipe_max_size_conv, ¶m); +} + static void validate_coredump_safety(void) {