Re: [patch 2/5] futex: Use futex_top_waiter() in lookup_pi_state()
On Wed, 2014-06-11 at 20:45 +, Thomas Gleixner wrote:
> No point in open coding the same function again.
>
> Signed-off-by: Thomas Gleixner
> ---
> kernel/futex.c | 128
> -
> 1 file changed, 63 insertions(+), 65 deletions(-)
>
> Index: linux/kernel/futex.c
> ===
> --- linux.orig/kernel/futex.c
> +++ linux/kernel/futex.c
> @@ -796,87 +796,85 @@ static int
> lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
> union futex_key *key, struct futex_pi_state **ps)
> {
> + struct futex_q *match = futex_top_waiter(hb, key);
> struct futex_pi_state *pi_state = NULL;
> - struct futex_q *this, *next;
> struct task_struct *p;
> pid_t pid = uval & FUTEX_TID_MASK;
>
> - plist_for_each_entry_safe(this, next, >chain, list) {
> - if (match_futex(>key, key)) {
> + if (match) {
> + /*
> +* Sanity check the waiter before increasing the
> +* refcount and attaching to it.
> +*/
> + pi_state = match->pi_state;
> + /*
> +* Userspace might have messed up non-PI and PI
> +* futexes [3]
> +*/
> + if (unlikely(!pi_state))
> + return -EINVAL;
> +
> + WARN_ON(!atomic_read(_state->refcount));
> +
> + /*
> +* Handle the owner died case:
> +*/
> + if (uval & FUTEX_OWNER_DIED) {
> /*
> -* Sanity check the waiter before increasing
> -* the refcount and attaching to it.
> +* exit_pi_state_list sets owner to NULL and
> +* wakes the topmost waiter. The task which
> +* acquires the pi_state->rt_mutex will fixup
> +* owner.
> */
> - pi_state = this->pi_state;
> - /*
> -* Userspace might have messed up non-PI and
> -* PI futexes [3]
> -*/
> - if (unlikely(!pi_state))
> - return -EINVAL;
> -
> - WARN_ON(!atomic_read(_state->refcount));
> -
> - /*
> -* Handle the owner died case:
> -*/
> - if (uval & FUTEX_OWNER_DIED) {
> - /*
> -* exit_pi_state_list sets owner to
> NULL and
> -* wakes the topmost waiter. The task
> which
> -* acquires the pi_state->rt_mutex
> will fixup
> -* owner.
> -*/
> - if (!pi_state->owner) {
> - /*
> -* No pi state owner, but the
> user
> -* space TID is not 0.
> Inconsistent
> -* state. [5]
> -*/
> - if (pid)
> - return -EINVAL;
> - /*
> -* Take a ref on the state and
> -* return. [4]
> -*/
> - goto out_state;
> - }
> -
> + if (!pi_state->owner) {
> /*
> -* If TID is 0, then either the dying
> owner
> -* has not yet executed
> exit_pi_state_list()
> -* or some waiter acquired the rtmutex
> in the
> -* pi state, but did not yet fixup the
> TID in
> -* user space.
> -*
> -* Take a ref on the state and return.
> [6]
> +* No pi state owner, but the user
> +* space TID is not 0. Inconsistent
> +* state. [5]
> */
> - if (!pid)
> - goto out_state;
> - } else {
> + if (pid)
> + return -EINVAL;
> /*
> -* If the owner died bit is not set,
> -* then
Re: [patch 2/5] futex: Use futex_top_waiter() in lookup_pi_state()
On Wed, 2014-06-11 at 20:45 +, Thomas Gleixner wrote:
No point in open coding the same function again.
Signed-off-by: Thomas Gleixner t...@linutronix.de
---
kernel/futex.c | 128
-
1 file changed, 63 insertions(+), 65 deletions(-)
Index: linux/kernel/futex.c
===
--- linux.orig/kernel/futex.c
+++ linux/kernel/futex.c
@@ -796,87 +796,85 @@ static int
lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
union futex_key *key, struct futex_pi_state **ps)
{
+ struct futex_q *match = futex_top_waiter(hb, key);
struct futex_pi_state *pi_state = NULL;
- struct futex_q *this, *next;
struct task_struct *p;
pid_t pid = uval FUTEX_TID_MASK;
- plist_for_each_entry_safe(this, next, hb-chain, list) {
- if (match_futex(this-key, key)) {
+ if (match) {
+ /*
+* Sanity check the waiter before increasing the
+* refcount and attaching to it.
+*/
+ pi_state = match-pi_state;
+ /*
+* Userspace might have messed up non-PI and PI
+* futexes [3]
+*/
+ if (unlikely(!pi_state))
+ return -EINVAL;
+
+ WARN_ON(!atomic_read(pi_state-refcount));
+
+ /*
+* Handle the owner died case:
+*/
+ if (uval FUTEX_OWNER_DIED) {
/*
-* Sanity check the waiter before increasing
-* the refcount and attaching to it.
+* exit_pi_state_list sets owner to NULL and
+* wakes the topmost waiter. The task which
+* acquires the pi_state-rt_mutex will fixup
+* owner.
*/
- pi_state = this-pi_state;
- /*
-* Userspace might have messed up non-PI and
-* PI futexes [3]
-*/
- if (unlikely(!pi_state))
- return -EINVAL;
-
- WARN_ON(!atomic_read(pi_state-refcount));
-
- /*
-* Handle the owner died case:
-*/
- if (uval FUTEX_OWNER_DIED) {
- /*
-* exit_pi_state_list sets owner to
NULL and
-* wakes the topmost waiter. The task
which
-* acquires the pi_state-rt_mutex
will fixup
-* owner.
-*/
- if (!pi_state-owner) {
- /*
-* No pi state owner, but the
user
-* space TID is not 0.
Inconsistent
-* state. [5]
-*/
- if (pid)
- return -EINVAL;
- /*
-* Take a ref on the state and
-* return. [4]
-*/
- goto out_state;
- }
-
+ if (!pi_state-owner) {
/*
-* If TID is 0, then either the dying
owner
-* has not yet executed
exit_pi_state_list()
-* or some waiter acquired the rtmutex
in the
-* pi state, but did not yet fixup the
TID in
-* user space.
-*
-* Take a ref on the state and return.
[6]
+* No pi state owner, but the user
+* space TID is not 0. Inconsistent
+* state. [5]
*/
- if (!pid)
- goto out_state;
- } else {
+ if (pid)
+ return -EINVAL;
/*
-* If the owner died bit is not set,
-* then the pi_state must have an
-* owner. [7]
+
[patch 2/5] futex: Use futex_top_waiter() in lookup_pi_state()
No point in open coding the same function again.
Signed-off-by: Thomas Gleixner
---
kernel/futex.c | 128 -
1 file changed, 63 insertions(+), 65 deletions(-)
Index: linux/kernel/futex.c
===
--- linux.orig/kernel/futex.c
+++ linux/kernel/futex.c
@@ -796,87 +796,85 @@ static int
lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
union futex_key *key, struct futex_pi_state **ps)
{
+ struct futex_q *match = futex_top_waiter(hb, key);
struct futex_pi_state *pi_state = NULL;
- struct futex_q *this, *next;
struct task_struct *p;
pid_t pid = uval & FUTEX_TID_MASK;
- plist_for_each_entry_safe(this, next, >chain, list) {
- if (match_futex(>key, key)) {
+ if (match) {
+ /*
+* Sanity check the waiter before increasing the
+* refcount and attaching to it.
+*/
+ pi_state = match->pi_state;
+ /*
+* Userspace might have messed up non-PI and PI
+* futexes [3]
+*/
+ if (unlikely(!pi_state))
+ return -EINVAL;
+
+ WARN_ON(!atomic_read(_state->refcount));
+
+ /*
+* Handle the owner died case:
+*/
+ if (uval & FUTEX_OWNER_DIED) {
/*
-* Sanity check the waiter before increasing
-* the refcount and attaching to it.
+* exit_pi_state_list sets owner to NULL and
+* wakes the topmost waiter. The task which
+* acquires the pi_state->rt_mutex will fixup
+* owner.
*/
- pi_state = this->pi_state;
- /*
-* Userspace might have messed up non-PI and
-* PI futexes [3]
-*/
- if (unlikely(!pi_state))
- return -EINVAL;
-
- WARN_ON(!atomic_read(_state->refcount));
-
- /*
-* Handle the owner died case:
-*/
- if (uval & FUTEX_OWNER_DIED) {
- /*
-* exit_pi_state_list sets owner to NULL and
-* wakes the topmost waiter. The task which
-* acquires the pi_state->rt_mutex will fixup
-* owner.
-*/
- if (!pi_state->owner) {
- /*
-* No pi state owner, but the user
-* space TID is not 0. Inconsistent
-* state. [5]
-*/
- if (pid)
- return -EINVAL;
- /*
-* Take a ref on the state and
-* return. [4]
-*/
- goto out_state;
- }
-
+ if (!pi_state->owner) {
/*
-* If TID is 0, then either the dying owner
-* has not yet executed exit_pi_state_list()
-* or some waiter acquired the rtmutex in the
-* pi state, but did not yet fixup the TID in
-* user space.
-*
-* Take a ref on the state and return. [6]
+* No pi state owner, but the user
+* space TID is not 0. Inconsistent
+* state. [5]
*/
- if (!pid)
- goto out_state;
- } else {
+ if (pid)
+ return -EINVAL;
/*
-* If the owner died bit is not set,
-* then the pi_state must have an
-* owner. [7]
+* Take a ref on the state and
+* return. [4]
*/
- if (!pi_state->owner)
-
[patch 2/5] futex: Use futex_top_waiter() in lookup_pi_state()
No point in open coding the same function again.
Signed-off-by: Thomas Gleixner t...@linutronix.de
---
kernel/futex.c | 128 -
1 file changed, 63 insertions(+), 65 deletions(-)
Index: linux/kernel/futex.c
===
--- linux.orig/kernel/futex.c
+++ linux/kernel/futex.c
@@ -796,87 +796,85 @@ static int
lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
union futex_key *key, struct futex_pi_state **ps)
{
+ struct futex_q *match = futex_top_waiter(hb, key);
struct futex_pi_state *pi_state = NULL;
- struct futex_q *this, *next;
struct task_struct *p;
pid_t pid = uval FUTEX_TID_MASK;
- plist_for_each_entry_safe(this, next, hb-chain, list) {
- if (match_futex(this-key, key)) {
+ if (match) {
+ /*
+* Sanity check the waiter before increasing the
+* refcount and attaching to it.
+*/
+ pi_state = match-pi_state;
+ /*
+* Userspace might have messed up non-PI and PI
+* futexes [3]
+*/
+ if (unlikely(!pi_state))
+ return -EINVAL;
+
+ WARN_ON(!atomic_read(pi_state-refcount));
+
+ /*
+* Handle the owner died case:
+*/
+ if (uval FUTEX_OWNER_DIED) {
/*
-* Sanity check the waiter before increasing
-* the refcount and attaching to it.
+* exit_pi_state_list sets owner to NULL and
+* wakes the topmost waiter. The task which
+* acquires the pi_state-rt_mutex will fixup
+* owner.
*/
- pi_state = this-pi_state;
- /*
-* Userspace might have messed up non-PI and
-* PI futexes [3]
-*/
- if (unlikely(!pi_state))
- return -EINVAL;
-
- WARN_ON(!atomic_read(pi_state-refcount));
-
- /*
-* Handle the owner died case:
-*/
- if (uval FUTEX_OWNER_DIED) {
- /*
-* exit_pi_state_list sets owner to NULL and
-* wakes the topmost waiter. The task which
-* acquires the pi_state-rt_mutex will fixup
-* owner.
-*/
- if (!pi_state-owner) {
- /*
-* No pi state owner, but the user
-* space TID is not 0. Inconsistent
-* state. [5]
-*/
- if (pid)
- return -EINVAL;
- /*
-* Take a ref on the state and
-* return. [4]
-*/
- goto out_state;
- }
-
+ if (!pi_state-owner) {
/*
-* If TID is 0, then either the dying owner
-* has not yet executed exit_pi_state_list()
-* or some waiter acquired the rtmutex in the
-* pi state, but did not yet fixup the TID in
-* user space.
-*
-* Take a ref on the state and return. [6]
+* No pi state owner, but the user
+* space TID is not 0. Inconsistent
+* state. [5]
*/
- if (!pid)
- goto out_state;
- } else {
+ if (pid)
+ return -EINVAL;
/*
-* If the owner died bit is not set,
-* then the pi_state must have an
-* owner. [7]
+* Take a ref on the state and
+* return. [4]
*/
- if (!pi_state-owner)
-
