From 01f8fa4f01d8362358eb90e412bd7ae18a3ec1ad Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 16 Apr 2014 14:36:44 +0000 Subject: genirq: Allow forcing cpu affinity of interrupts The current implementation of irq_set_affinity() refuses rightfully to route an interrupt to an offline cpu. But there is a special case, where this is actually desired. Some of the ARM SoCs have per cpu timers which require setting the affinity during cpu startup where the cpu is not yet in the online mask. If we can't do that, then the local timer interrupt for the about to become online cpu is routed to some random online cpu. The developers of the affected machines tried to work around that issue, but that results in a massive mess in that timer code. We have a yet unused argument in the set_affinity callbacks of the irq chips, which I added back then for a similar reason. It was never required so it got not used. But I'm happy that I never removed it. That allows us to implement a sane handling of the above scenario. So the affected SoC drivers can add the required force handling to their interrupt chip, switch the timer code to irq_force_affinity() and things just work. This does not affect any existing user of irq_set_affinity(). Tagged for stable to allow a simple fix of the affected SoC clock event drivers. Reported-and-tested-by: Krzysztof Kozlowski Signed-off-by: Thomas Gleixner Cc: Kyungmin Park Cc: Marek Szyprowski Cc: Bartlomiej Zolnierkiewicz Cc: Tomasz Figa , Cc: Daniel Lezcano , Cc: Kukjin Kim Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143315.717251504@linutronix.de Signed-off-by: Thomas Gleixner --- include/linux/interrupt.h | 35 ++++++++++++++++++++++++++++++++++- include/linux/irq.h | 3 ++- 2 files changed, 36 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index c7bfac1c4a7b..8834a7e5b944 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -203,7 +203,40 @@ static inline int check_wakeup_irqs(void) { return 0; } extern cpumask_var_t irq_default_affinity; -extern int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask); +/* Internal implementation. Use the helpers below */ +extern int __irq_set_affinity(unsigned int irq, const struct cpumask *cpumask, + bool force); + +/** + * irq_set_affinity - Set the irq affinity of a given irq + * @irq: Interrupt to set affinity + * @mask: cpumask + * + * Fails if cpumask does not contain an online CPU + */ +static inline int +irq_set_affinity(unsigned int irq, const struct cpumask *cpumask) +{ + return __irq_set_affinity(irq, cpumask, false); +} + +/** + * irq_force_affinity - Force the irq affinity of a given irq + * @irq: Interrupt to set affinity + * @mask: cpumask + * + * Same as irq_set_affinity, but without checking the mask against + * online cpus. + * + * Solely for low level cpu hotplug code, where we need to make per + * cpu interrupts affine before the cpu becomes online. + */ +static inline int +irq_force_affinity(unsigned int irq, const struct cpumask *cpumask) +{ + return __irq_set_affinity(irq, cpumask, true); +} + extern int irq_can_set_affinity(unsigned int irq); extern int irq_select_affinity(unsigned int irq); diff --git a/include/linux/irq.h b/include/linux/irq.h index d278838908cb..10a0b1ac4ea0 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -394,7 +394,8 @@ extern void remove_percpu_irq(unsigned int irq, struct irqaction *act); extern void irq_cpu_online(void); extern void irq_cpu_offline(void); -extern int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *cpumask); +extern int irq_set_affinity_locked(struct irq_data *data, + const struct cpumask *cpumask, bool force); #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_PENDING_IRQ) void irq_move_irq(struct irq_data *data); -- cgit v1.2.3-71-gd317 From df7926fffa9a4c0bceb0189386b4c5edc012fcbb Mon Sep 17 00:00:00 2001 From: Tim Kryger Date: Thu, 17 Apr 2014 11:55:24 -0700 Subject: regulator: core: Return error in get optional stub Drivers that call regulator_get_optional are tolerant to the absence of that regulator. By modifying the value returned from the stub function to match that seen when a regulator isn't present, callers can wrap the regulator logic with an IS_ERR based conditional even if they happen to call regulator_is_supported_voltage. This improves efficiency as well as eliminates the possibility for a very subtle bug. Signed-off-by: Tim Kryger Reviewed-by: Alex Elder Signed-off-by: Mark Brown --- include/linux/regulator/consumer.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h index e530681bea70..1a4a8c157b31 100644 --- a/include/linux/regulator/consumer.h +++ b/include/linux/regulator/consumer.h @@ -258,14 +258,14 @@ regulator_get_exclusive(struct device *dev, const char *id) static inline struct regulator *__must_check regulator_get_optional(struct device *dev, const char *id) { - return NULL; + return ERR_PTR(-ENODEV); } static inline struct regulator *__must_check devm_regulator_get_optional(struct device *dev, const char *id) { - return NULL; + return ERR_PTR(-ENODEV); } static inline void regulator_put(struct regulator *regulator) -- cgit v1.2.3-71-gd317 From 8a4aeec8d2d6a3edeffbdfae451cdf05cbf0fefd Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 17 Apr 2014 11:48:21 -0700 Subject: libata/ahci: accommodate tag ordered controllers The AHCI spec allows implementations to issue commands in tag order rather than FIFO order: 5.3.2.12 P:SelectCmd HBA sets pSlotLoc = (pSlotLoc + 1) mod (CAP.NCS + 1) or HBA selects the command to issue that has had the PxCI bit set to '1' longer than any other command pending to be issued. The result is that commands posted sequentially (time-wise) may play out of sequence when issued by hardware. This behavior has likely been hidden by drives that arrange for commands to complete in issue order. However, it appears recent drives (two from different vendors that we have found so far) inflict out-of-order completions as a matter of course. So, we need to take care to maintain ordered submission, otherwise we risk triggering a drive to fall out of sequential-io automation and back to random-io processing, which incurs large latency and degrades throughput. This issue was found in simple benchmarks where QD=2 seq-write performance was 30-50% *greater* than QD=32 seq-write performance. Tagging for -stable and making the change globally since it has a low risk-to-reward ratio. Also, word is that recent versions of an unnamed OS also does it this way now. So, drives in the field are already experienced with this tag ordering scheme. Cc: Cc: Dave Jiang Cc: Ed Ciechanowski Reviewed-by: Matthew Wilcox Signed-off-by: Dan Williams Signed-off-by: Tejun Heo --- drivers/ata/libata-core.c | 21 +++++++++++++-------- include/linux/libata.h | 1 + 2 files changed, 14 insertions(+), 8 deletions(-) (limited to 'include/linux') diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index f2a6020366e1..73c5d0410d47 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -4794,21 +4794,26 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words) static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap) { struct ata_queued_cmd *qc = NULL; - unsigned int i; + unsigned int i, tag; /* no command while frozen */ if (unlikely(ap->pflags & ATA_PFLAG_FROZEN)) return NULL; - /* the last tag is reserved for internal command. */ - for (i = 0; i < ATA_MAX_QUEUE - 1; i++) - if (!test_and_set_bit(i, &ap->qc_allocated)) { - qc = __ata_qc_from_tag(ap, i); + for (i = 0; i < ATA_MAX_QUEUE; i++) { + tag = (i + ap->last_tag + 1) % ATA_MAX_QUEUE; + + /* the last tag is reserved for internal command. */ + if (tag == ATA_TAG_INTERNAL) + continue; + + if (!test_and_set_bit(tag, &ap->qc_allocated)) { + qc = __ata_qc_from_tag(ap, tag); + qc->tag = tag; + ap->last_tag = tag; break; } - - if (qc) - qc->tag = i; + } return qc; } diff --git a/include/linux/libata.h b/include/linux/libata.h index 1de36be64df4..5ab4e3a76721 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -822,6 +822,7 @@ struct ata_port { unsigned long qc_allocated; unsigned int qc_active; int nr_active_links; /* #links with active qcs */ + unsigned int last_tag; /* track next tag hw expects */ struct ata_link link; /* host default link */ struct ata_link *slave_link; /* see ata_slave_link_init() */ -- cgit v1.2.3-71-gd317 From 0456c66f4e905e1ca839318219c770988b47975c Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sat, 19 Apr 2014 20:39:35 -0700 Subject: Input: serio - add firmware_id sysfs attribute serio devices exposed via platform firmware interfaces such as ACPI may provide additional identifying information of use to userspace. We don't associate the serio devices with the firmware device (we don't set it as parent), so there's no way for userspace to make use of this information. We cannot change the parent for serio devices instantiated though a firmware interface as that would break suspend / resume ordering. Therefore this patch adds a new firmware_id sysfs attribute so that userspace can get a string from there with any additional identifying information the firmware interface may provide. Signed-off-by: Hans de Goede Acked-by: Peter Hutterer Signed-off-by: Dmitry Torokhov --- drivers/input/serio/serio.c | 14 ++++++++++++++ include/linux/serio.h | 1 + 2 files changed, 15 insertions(+) (limited to 'include/linux') diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c index 8f4c4ab04bc2..b29134de983b 100644 --- a/drivers/input/serio/serio.c +++ b/drivers/input/serio/serio.c @@ -451,6 +451,13 @@ static ssize_t serio_set_bind_mode(struct device *dev, struct device_attribute * return retval; } +static ssize_t firmware_id_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct serio *serio = to_serio_port(dev); + + return sprintf(buf, "%s\n", serio->firmware_id); +} + static DEVICE_ATTR_RO(type); static DEVICE_ATTR_RO(proto); static DEVICE_ATTR_RO(id); @@ -473,12 +480,14 @@ static DEVICE_ATTR_RO(modalias); static DEVICE_ATTR_WO(drvctl); static DEVICE_ATTR(description, S_IRUGO, serio_show_description, NULL); static DEVICE_ATTR(bind_mode, S_IWUSR | S_IRUGO, serio_show_bind_mode, serio_set_bind_mode); +static DEVICE_ATTR_RO(firmware_id); static struct attribute *serio_device_attrs[] = { &dev_attr_modalias.attr, &dev_attr_description.attr, &dev_attr_drvctl.attr, &dev_attr_bind_mode.attr, + &dev_attr_firmware_id.attr, NULL }; @@ -921,9 +930,14 @@ static int serio_uevent(struct device *dev, struct kobj_uevent_env *env) SERIO_ADD_UEVENT_VAR("SERIO_PROTO=%02x", serio->id.proto); SERIO_ADD_UEVENT_VAR("SERIO_ID=%02x", serio->id.id); SERIO_ADD_UEVENT_VAR("SERIO_EXTRA=%02x", serio->id.extra); + SERIO_ADD_UEVENT_VAR("MODALIAS=serio:ty%02Xpr%02Xid%02Xex%02X", serio->id.type, serio->id.proto, serio->id.id, serio->id.extra); + if (serio->firmware_id[0]) + SERIO_ADD_UEVENT_VAR("SERIO_FIRMWARE_ID=%s", + serio->firmware_id); + return 0; } #undef SERIO_ADD_UEVENT_VAR diff --git a/include/linux/serio.h b/include/linux/serio.h index 36aac733840a..9f779c7a2da4 100644 --- a/include/linux/serio.h +++ b/include/linux/serio.h @@ -23,6 +23,7 @@ struct serio { char name[32]; char phys[32]; + char firmware_id[128]; bool manual_bind; -- cgit v1.2.3-71-gd317 From cff2fce58b2b0f59089e7edcdc38803d65057b9f Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 22 Apr 2014 08:24:32 -0400 Subject: locks: rename FL_FILE_PVT and IS_FILE_PVT to use "*_OFDLCK" instead File-private locks have been re-christened as "open file description" locks. Finish the symbol name cleanup in the internal implementation. Signed-off-by: Jeff Layton --- fs/locks.c | 34 +++++++++++++++++----------------- include/linux/fs.h | 2 +- 2 files changed, 18 insertions(+), 18 deletions(-) (limited to 'include/linux') diff --git a/fs/locks.c b/fs/locks.c index e1023b504279..e663aeac579e 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -135,7 +135,7 @@ #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX) #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK) #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG)) -#define IS_FILE_PVT(fl) (fl->fl_flags & FL_FILE_PVT) +#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK) static bool lease_breaking(struct file_lock *fl) { @@ -564,7 +564,7 @@ static void __locks_insert_block(struct file_lock *blocker, BUG_ON(!list_empty(&waiter->fl_block)); waiter->fl_next = blocker; list_add_tail(&waiter->fl_block, &blocker->fl_block); - if (IS_POSIX(blocker) && !IS_FILE_PVT(blocker)) + if (IS_POSIX(blocker) && !IS_OFDLCK(blocker)) locks_insert_global_blocked(waiter); } @@ -759,12 +759,12 @@ EXPORT_SYMBOL(posix_test_lock); * of tasks (such as posix threads) sharing the same open file table. * To handle those cases, we just bail out after a few iterations. * - * For FL_FILE_PVT locks, the owner is the filp, not the files_struct. + * For FL_OFDLCK locks, the owner is the filp, not the files_struct. * Because the owner is not even nominally tied to a thread of * execution, the deadlock detection below can't reasonably work well. Just * skip it for those. * - * In principle, we could do a more limited deadlock detection on FL_FILE_PVT + * In principle, we could do a more limited deadlock detection on FL_OFDLCK * locks that just checks for the case where two tasks are attempting to * upgrade from read to write locks on the same inode. */ @@ -791,9 +791,9 @@ static int posix_locks_deadlock(struct file_lock *caller_fl, /* * This deadlock detector can't reasonably detect deadlocks with - * FL_FILE_PVT locks, since they aren't owned by a process, per-se. + * FL_OFDLCK locks, since they aren't owned by a process, per-se. */ - if (IS_FILE_PVT(caller_fl)) + if (IS_OFDLCK(caller_fl)) return 0; while ((block_fl = what_owner_is_waiting_for(block_fl))) { @@ -1890,7 +1890,7 @@ EXPORT_SYMBOL_GPL(vfs_test_lock); static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) { - flock->l_pid = IS_FILE_PVT(fl) ? -1 : fl->fl_pid; + flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid; #if BITS_PER_LONG == 32 /* * Make sure we can represent the posix lock via @@ -1912,7 +1912,7 @@ static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) #if BITS_PER_LONG == 32 static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl) { - flock->l_pid = IS_FILE_PVT(fl) ? -1 : fl->fl_pid; + flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid; flock->l_start = fl->fl_start; flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : fl->fl_end - fl->fl_start + 1; @@ -1947,7 +1947,7 @@ int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l) goto out; cmd = F_GETLK; - file_lock.fl_flags |= FL_FILE_PVT; + file_lock.fl_flags |= FL_OFDLCK; file_lock.fl_owner = (fl_owner_t)filp; } @@ -2073,7 +2073,7 @@ again: /* * If the cmd is requesting file-private locks, then set the - * FL_FILE_PVT flag and override the owner. + * FL_OFDLCK flag and override the owner. */ switch (cmd) { case F_OFD_SETLK: @@ -2082,7 +2082,7 @@ again: goto out; cmd = F_SETLK; - file_lock->fl_flags |= FL_FILE_PVT; + file_lock->fl_flags |= FL_OFDLCK; file_lock->fl_owner = (fl_owner_t)filp; break; case F_OFD_SETLKW: @@ -2091,7 +2091,7 @@ again: goto out; cmd = F_SETLKW; - file_lock->fl_flags |= FL_FILE_PVT; + file_lock->fl_flags |= FL_OFDLCK; file_lock->fl_owner = (fl_owner_t)filp; /* Fallthrough */ case F_SETLKW: @@ -2149,7 +2149,7 @@ int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l) goto out; cmd = F_GETLK64; - file_lock.fl_flags |= FL_FILE_PVT; + file_lock.fl_flags |= FL_OFDLCK; file_lock.fl_owner = (fl_owner_t)filp; } @@ -2208,7 +2208,7 @@ again: /* * If the cmd is requesting file-private locks, then set the - * FL_FILE_PVT flag and override the owner. + * FL_OFDLCK flag and override the owner. */ switch (cmd) { case F_OFD_SETLK: @@ -2217,7 +2217,7 @@ again: goto out; cmd = F_SETLK64; - file_lock->fl_flags |= FL_FILE_PVT; + file_lock->fl_flags |= FL_OFDLCK; file_lock->fl_owner = (fl_owner_t)filp; break; case F_OFD_SETLKW: @@ -2226,7 +2226,7 @@ again: goto out; cmd = F_SETLKW64; - file_lock->fl_flags |= FL_FILE_PVT; + file_lock->fl_flags |= FL_OFDLCK; file_lock->fl_owner = (fl_owner_t)filp; /* Fallthrough */ case F_SETLKW64: @@ -2412,7 +2412,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, if (IS_POSIX(fl)) { if (fl->fl_flags & FL_ACCESS) seq_printf(f, "ACCESS"); - else if (IS_FILE_PVT(fl)) + else if (IS_OFDLCK(fl)) seq_printf(f, "OFDLCK"); else seq_printf(f, "POSIX "); diff --git a/include/linux/fs.h b/include/linux/fs.h index 7a9c5bca2b76..878031227c57 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -815,7 +815,7 @@ static inline struct file *get_file(struct file *f) #define FL_SLEEP 128 /* A blocking lock */ #define FL_DOWNGRADE_PENDING 256 /* Lease is being downgraded */ #define FL_UNLOCK_PENDING 512 /* Lease is being broken */ -#define FL_FILE_PVT 1024 /* lock is private to the file */ +#define FL_OFDLCK 1024 /* lock is "owned" by struct file */ /* * Special return value from posix_lock_file() and vfs_lock_file() for -- cgit v1.2.3-71-gd317 From 2b97789fa289d531e767d994a77e34ec58f328c4 Mon Sep 17 00:00:00 2001 From: Grygorii Strashko Date: Sat, 19 Apr 2014 08:51:44 +0530 Subject: phy: core: make NULL a valid phy reference if !CONFIG_GENERIC_PHY This fixes a regression on Keystone 2 platforms caused by patch 57303488cd37da58263e842de134dc65f7c626d5 "usb: dwc3: adapt dwc3 core to use Generic PHY Framework" which adds optional support of generic phy in DWC3 core. On Keystone 2 platforms the USB is not working now because CONFIG_GENERIC_PHY isn't set and, as result, Generic PHY APIs stubs return -ENOSYS always. The log shows: dwc3 2690000.dwc3: failed to initialize core dwc3: probe of 2690000.dwc3 failed with error -38 Hence, fix it by making NULL a valid phy reference in Generic PHY APIs stubs in the same way as it was done by the patch 04c2facad8fee66c981a51852806d8923336f362 "drivers: phy: Make NULL a valid phy reference". Acked-by: Felipe Balbi Acked-by: Santosh Shilimkar Signed-off-by: Grygorii Strashko Signed-off-by: Kishon Vijay Abraham I Signed-off-by: Greg Kroah-Hartman --- include/linux/phy/phy.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux') diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h index e2f5ca96cddc..2760744cb2a7 100644 --- a/include/linux/phy/phy.h +++ b/include/linux/phy/phy.h @@ -174,21 +174,29 @@ void devm_of_phy_provider_unregister(struct device *dev, #else static inline int phy_pm_runtime_get(struct phy *phy) { + if (!phy) + return 0; return -ENOSYS; } static inline int phy_pm_runtime_get_sync(struct phy *phy) { + if (!phy) + return 0; return -ENOSYS; } static inline int phy_pm_runtime_put(struct phy *phy) { + if (!phy) + return 0; return -ENOSYS; } static inline int phy_pm_runtime_put_sync(struct phy *phy) { + if (!phy) + return 0; return -ENOSYS; } @@ -204,21 +212,29 @@ static inline void phy_pm_runtime_forbid(struct phy *phy) static inline int phy_init(struct phy *phy) { + if (!phy) + return 0; return -ENOSYS; } static inline int phy_exit(struct phy *phy) { + if (!phy) + return 0; return -ENOSYS; } static inline int phy_power_on(struct phy *phy) { + if (!phy) + return 0; return -ENOSYS; } static inline int phy_power_off(struct phy *phy) { + if (!phy) + return 0; return -ENOSYS; } -- cgit v1.2.3-71-gd317 From 6a20dbd6caa2358716136144bf524331d70b1e03 Mon Sep 17 00:00:00 2001 From: Manfred Schlaegl Date: Tue, 8 Apr 2014 14:42:04 +0200 Subject: tty: Fix race condition between __tty_buffer_request_room and flush_to_ldisc The race was introduced while development of linux-3.11 by e8437d7ecbc50198705331449367d401ebb3181f and e9975fdec0138f1b2a85b9624e41660abd9865d4. Originally it was found and reproduced on linux-3.12.15 and linux-3.12.15-rt25, by sending 500 byte blocks with 115kbaud to the target uart in a loop with 100 milliseconds delay. In short: 1. The consumer flush_to_ldisc is on to remove the head tty_buffer. 2. The producer adds a number of bytes, so that a new tty_buffer must be allocated and added by __tty_buffer_request_room. 3. The consumer removes the head tty_buffer element, without handling newly committed data. Detailed example: * Initial buffer: * Head, Tail -> 0: used=250; commit=250; read=240; next=NULL * Consumer: ''flush_to_ldisc'' * consumed 10 Byte * buffer: * Head, Tail -> 0: used=250; commit=250; read=250; next=NULL {{{ count = head->commit - head->read; // count = 0 if (!count) { // enter // INTERRUPTED BY PRODUCER -> if (head->next == NULL) break; buf->head = head->next; tty_buffer_free(port, head); continue; } }}} * Producer: tty_insert_flip_... 10 bytes + tty_flip_buffer_push * buffer: * Head, Tail -> 0: used=250; commit=250; read=250; next=NULL * added 6 bytes: head-element filled to maximum. * buffer: * Head, Tail -> 0: used=256; commit=250; read=250; next=NULL * added 4 bytes: __tty_buffer_request_room is called * buffer: * Head -> 0: used=256; commit=256; read=250; next=1 * Tail -> 1: used=4; commit=0; read=250 next=NULL * push (tty_flip_buffer_push) * buffer: * Head -> 0: used=256; commit=256; read=250; next=1 * Tail -> 1: used=4; commit=4; read=250 next=NULL * Consumer {{{ count = head->commit - head->read; if (!count) { // INTERRUPTED BY PRODUCER <- if (head->next == NULL) // -> no break break; buf->head = head->next; tty_buffer_free(port, head); // ERROR: tty_buffer head freed -> 6 bytes lost continue; } }}} This patch reintroduces a spin_lock to protect this case. Perhaps later a lock-less solution could be found. Signed-off-by: Manfred Schlaegl Cc: stable # 3.11 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 16 ++++++++++++++-- include/linux/tty.h | 1 + 2 files changed, 15 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 8ebd9f88a6f6..f1d30f6945af 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -255,11 +255,16 @@ static int __tty_buffer_request_room(struct tty_port *port, size_t size, if (change || left < size) { /* This is the slow path - looking for new buffers to use */ if ((n = tty_buffer_alloc(port, size)) != NULL) { + unsigned long iflags; + n->flags = flags; buf->tail = n; + + spin_lock_irqsave(&buf->flush_lock, iflags); b->commit = b->used; - smp_mb(); b->next = n; + spin_unlock_irqrestore(&buf->flush_lock, iflags); + } else if (change) size = 0; else @@ -443,6 +448,7 @@ static void flush_to_ldisc(struct work_struct *work) mutex_lock(&buf->lock); while (1) { + unsigned long flags; struct tty_buffer *head = buf->head; int count; @@ -450,14 +456,19 @@ static void flush_to_ldisc(struct work_struct *work) if (atomic_read(&buf->priority)) break; + spin_lock_irqsave(&buf->flush_lock, flags); count = head->commit - head->read; if (!count) { - if (head->next == NULL) + if (head->next == NULL) { + spin_unlock_irqrestore(&buf->flush_lock, flags); break; + } buf->head = head->next; + spin_unlock_irqrestore(&buf->flush_lock, flags); tty_buffer_free(port, head); continue; } + spin_unlock_irqrestore(&buf->flush_lock, flags); count = receive_buf(tty, head, count); if (!count) @@ -512,6 +523,7 @@ void tty_buffer_init(struct tty_port *port) struct tty_bufhead *buf = &port->buf; mutex_init(&buf->lock); + spin_lock_init(&buf->flush_lock); tty_buffer_reset(&buf->sentinel, 0); buf->head = &buf->sentinel; buf->tail = &buf->sentinel; diff --git a/include/linux/tty.h b/include/linux/tty.h index 1c3316a47d7e..036cccd80d9f 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -61,6 +61,7 @@ struct tty_bufhead { struct tty_buffer *head; /* Queue head */ struct work_struct work; struct mutex lock; + spinlock_t flush_lock; atomic_t priority; struct tty_buffer sentinel; struct llist_head free; /* Free queue head */ -- cgit v1.2.3-71-gd317