From 0baab86b00cdf9785ac2bb2ce1ab63995b3866ca Mon Sep 17 00:00:00 2001 From: Edward Falk Date: Thu, 2 Jun 2005 18:17:13 -0400 Subject: libata: update inline source docs --- include/linux/libata.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) (limited to 'include/linux') diff --git a/include/linux/libata.h b/include/linux/libata.h index 1f7e2039a04e..ad410590664f 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -466,12 +466,34 @@ static inline u8 ata_chk_status(struct ata_port *ap) return ap->ops->check_status(ap); } + +/** + * ata_pause - Flush writes and pause 400 nanoseconds. + * @ap: Port to wait for. + * + * LOCKING: + * Inherited from caller. + */ + static inline void ata_pause(struct ata_port *ap) { ata_altstatus(ap); ndelay(400); } + +/** + * ata_busy_wait - Wait for a port status register + * @ap: Port to wait for. + * + * Waits up to max*10 microseconds for the selected bits in the port's + * status register to be cleared. + * Returns final value of status register. + * + * LOCKING: + * Inherited from caller. + */ + static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits, unsigned int max) { @@ -486,6 +508,18 @@ static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits, return status; } + +/** + * ata_wait_idle - Wait for a port to be idle. + * @ap: Port to wait for. + * + * Waits up to 10ms for port's BUSY and DRQ signals to clear. + * Returns final value of status register. + * + * LOCKING: + * Inherited from caller. + */ + static inline u8 ata_wait_idle(struct ata_port *ap) { u8 status = ata_busy_wait(ap, ATA_BUSY | ATA_DRQ, 1000); @@ -524,6 +558,18 @@ static inline void ata_tf_init(struct ata_port *ap, struct ata_taskfile *tf, uns tf->device = ATA_DEVICE_OBS | ATA_DEV1; } + +/** + * ata_irq_on - Enable interrupts on a port. + * @ap: Port on which interrupts are enabled. + * + * Enable interrupts on a legacy IDE device using MMIO or PIO, + * wait for idle, clear any pending interrupts. + * + * LOCKING: + * Inherited from caller. + */ + static inline u8 ata_irq_on(struct ata_port *ap) { struct ata_ioports *ioaddr = &ap->ioaddr; @@ -543,6 +589,18 @@ static inline u8 ata_irq_on(struct ata_port *ap) return tmp; } + +/** + * ata_irq_ack - Acknowledge a device interrupt. + * @ap: Port on which interrupts are enabled. + * + * Wait up to 10 ms for legacy IDE device to become idle (BUSY + * or BUSY+DRQ clear). Obtain dma status and port status from + * device. Clear the interrupt. Return port status. + * + * LOCKING: + */ + static inline u8 ata_irq_ack(struct ata_port *ap, unsigned int chk_drq) { unsigned int bits = chk_drq ? ATA_BUSY | ATA_DRQ : ATA_BUSY; -- cgit v1.2.3 From b597ef4712c05c962640a655386a7f06cc1a1fbc Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 2 Jun 2005 16:36:00 -0700 Subject: [NET]: Fix locking in shaper driver. o use a semaphore instead of an opencoded and racy lock o move locking out of shaper_kick and into the callers - most just released the lock before calling shaper_kick o remove in_interrupt() tests. from ->close we can always block, from ->hard_start_xmit and timer context never Signed-off-by: Christoph Hellwig Signed-off-by: David S. Miller --- drivers/net/shaper.c | 86 +++++++++++------------------------------------ include/linux/if_shaper.h | 3 +- 2 files changed, 20 insertions(+), 69 deletions(-) (limited to 'include/linux') diff --git a/drivers/net/shaper.c b/drivers/net/shaper.c index e68cf5fb4920..20edeb345792 100644 --- a/drivers/net/shaper.c +++ b/drivers/net/shaper.c @@ -100,35 +100,8 @@ static int sh_debug; /* Debug flag */ #define SHAPER_BANNER "CymruNet Traffic Shaper BETA 0.04 for Linux 2.1\n" -/* - * Locking - */ - -static int shaper_lock(struct shaper *sh) -{ - /* - * Lock in an interrupt must fail - */ - while (test_and_set_bit(0, &sh->locked)) - { - if (!in_interrupt()) - sleep_on(&sh->wait_queue); - else - return 0; - - } - return 1; -} - static void shaper_kick(struct shaper *sh); -static void shaper_unlock(struct shaper *sh) -{ - clear_bit(0, &sh->locked); - wake_up(&sh->wait_queue); - shaper_kick(sh); -} - /* * Compute clocks on a buffer */ @@ -157,17 +130,15 @@ static void shaper_setspeed(struct shaper *shaper, int bitspersec) * Throw a frame at a shaper. */ -static int shaper_qframe(struct shaper *shaper, struct sk_buff *skb) + +static int shaper_start_xmit(struct sk_buff *skb, struct net_device *dev) { + struct shaper *shaper = dev->priv; struct sk_buff *ptr; - /* - * Get ready to work on this shaper. Lock may fail if its - * an interrupt and locked. - */ - - if(!shaper_lock(shaper)) - return -1; + if (down_trylock(&shaper->sem)) + return -1; + ptr=shaper->sendq.prev; /* @@ -260,7 +231,8 @@ static int shaper_qframe(struct shaper *shaper, struct sk_buff *skb) dev_kfree_skb(ptr); shaper->stats.collisions++; } - shaper_unlock(shaper); + shaper_kick(shaper); + up(&shaper->sem); return 0; } @@ -297,8 +269,13 @@ static void shaper_queue_xmit(struct shaper *shaper, struct sk_buff *skb) static void shaper_timer(unsigned long data) { - struct shaper *sh=(struct shaper *)data; - shaper_kick(sh); + struct shaper *shaper = (struct shaper *)data; + + if (!down_trylock(&shaper->sem)) { + shaper_kick(shaper); + up(&shaper->sem); + } else + mod_timer(&shaper->timer, jiffies); } /* @@ -310,19 +287,6 @@ static void shaper_kick(struct shaper *shaper) { struct sk_buff *skb; - /* - * Shaper unlock will kick - */ - - if (test_and_set_bit(0, &shaper->locked)) - { - if(sh_debug) - printk("Shaper locked.\n"); - mod_timer(&shaper->timer, jiffies); - return; - } - - /* * Walk the list (may be empty) */ @@ -364,8 +328,6 @@ static void shaper_kick(struct shaper *shaper) if(skb!=NULL) mod_timer(&shaper->timer, SHAPERCB(skb)->shapeclock); - - clear_bit(0, &shaper->locked); } @@ -376,14 +338,12 @@ static void shaper_kick(struct shaper *shaper) static void shaper_flush(struct shaper *shaper) { struct sk_buff *skb; - if(!shaper_lock(shaper)) - { - printk(KERN_ERR "shaper: shaper_flush() called by an irq!\n"); - return; - } + + down(&shaper->sem); while((skb=skb_dequeue(&shaper->sendq))!=NULL) dev_kfree_skb(skb); - shaper_unlock(shaper); + shaper_kick(shaper); + up(&shaper->sem); } /* @@ -426,13 +386,6 @@ static int shaper_close(struct net_device *dev) * ARP and other resolutions and not before. */ - -static int shaper_start_xmit(struct sk_buff *skb, struct net_device *dev) -{ - struct shaper *sh=dev->priv; - return shaper_qframe(sh, skb); -} - static struct net_device_stats *shaper_get_stats(struct net_device *dev) { struct shaper *sh=dev->priv; @@ -623,7 +576,6 @@ static void shaper_init_priv(struct net_device *dev) init_timer(&sh->timer); sh->timer.function=shaper_timer; sh->timer.data=(unsigned long)sh; - init_waitqueue_head(&sh->wait_queue); } /* diff --git a/include/linux/if_shaper.h b/include/linux/if_shaper.h index 0485b256d043..004e6f09a6e2 100644 --- a/include/linux/if_shaper.h +++ b/include/linux/if_shaper.h @@ -23,7 +23,7 @@ struct shaper __u32 shapeclock; unsigned long recovery; /* Time we can next clock a packet out on an empty queue */ - unsigned long locked; + struct semaphore sem; struct net_device_stats stats; struct net_device *dev; int (*hard_start_xmit) (struct sk_buff *skb, @@ -38,7 +38,6 @@ struct shaper int (*hard_header_cache)(struct neighbour *neigh, struct hh_cache *hh); void (*header_cache_update)(struct hh_cache *hh, struct net_device *dev, unsigned char * haddr); struct net_device_stats* (*get_stats)(struct net_device *dev); - wait_queue_head_t wait_queue; struct timer_list timer; }; -- cgit v1.2.3 From 5ba0eac6e0b7e2889649a1105d97c600595e2bb1 Mon Sep 17 00:00:00 2001 From: Jiri Benc Date: Thu, 2 Jun 2005 16:48:05 -0700 Subject: [NET]: Fix HH_DATA_OFF. When the hardware header size is a multiple of HH_DATA_MOD, HH_DATA_OFF() incorrectly returns HH_DATA_MOD (instead of 0). This affects ieee80211 layer as 802.11 header is 32 bytes long. Signed-off-by: Jiri Benc Signed-off-by: David S. Miller --- include/linux/netdevice.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 470af8c1a4a0..ba5d1236aa17 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -204,7 +204,7 @@ struct hh_cache /* cached hardware header; allow for machine alignment needs. */ #define HH_DATA_MOD 16 #define HH_DATA_OFF(__len) \ - (HH_DATA_MOD - ((__len) & (HH_DATA_MOD - 1))) + (HH_DATA_MOD - (((__len - 1) & (HH_DATA_MOD - 1)) + 1)) #define HH_DATA_ALIGN(__len) \ (((__len)+(HH_DATA_MOD-1))&~(HH_DATA_MOD - 1)) unsigned long hh_data[HH_DATA_ALIGN(LL_MAX_HEADER) / sizeof(long)]; -- cgit v1.2.3 From 719df469cb51199316ae2a11c75a8046be34b899 Mon Sep 17 00:00:00 2001 From: Roman Kagan Date: Fri, 6 May 2005 00:55:56 +0400 Subject: [PATCH] USB: update urb documentation On Wed, May 04, 2005 at 01:37:30PM -0700, David Brownell wrote: > On Wednesday 04 May 2005 12:19 pm, Roman Kagan wrote: > > struct urb { > > /* private, usb core and host controller only fields in the urb */ > > ... > > struct list_head urb_list; /* list pointer to all active urbs */ > > ... > > }; > > > > Is it safe to use it for driver's purposes when the driver owns the urb, > > that is, starting from the completion routine until the urb is submitted > > with usb_submit_urb()? > > Right now, it should be. Great! FWIW I've briefly tested a modified version of usbatm using the list head in struct urb instead of creating a wrapper struct, and I haven't seen any failures yet. So I tend to believe that your "should be" actually means "is" :) > > If it is, can it be guaranteed in future, e.g. > > by moving the list head into the public section of struct urb? > > In fact I'm not sure why it ever got called "private" to usbcore/hcds. > I thought the idea was that it should be like urb->status, reserved for > whoever controls the URB. OK then how about the following (essentially documentation) patch? Signed-off-by: Roman Kagan Acked-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- include/linux/usb.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/usb.h b/include/linux/usb.h index 41d1a644c9d4..2d1ac5058534 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -796,6 +796,10 @@ typedef void (*usb_complete_t)(struct urb *, struct pt_regs *); * of the iso_frame_desc array, and the number of errors is reported in * error_count. Completion callbacks for ISO transfers will normally * (re)submit URBs to ensure a constant transfer rate. + * + * Note that even fields marked "public" should not be touched by the driver + * when the urb is owned by the hcd, that is, since the call to + * usb_submit_urb() till the entry into the completion routine. */ struct urb { @@ -803,12 +807,12 @@ struct urb struct kref kref; /* reference count of the URB */ spinlock_t lock; /* lock for the URB */ void *hcpriv; /* private data for host controller */ - struct list_head urb_list; /* list pointer to all active urbs */ int bandwidth; /* bandwidth for INT/ISO request */ atomic_t use_count; /* concurrent submissions counter */ u8 reject; /* submissions will fail */ /* public, documented fields in the urb that can be used by drivers */ + struct list_head urb_list; /* list head for use by the urb owner */ struct usb_device *dev; /* (in) pointer to associated device */ unsigned int pipe; /* (in) pipe information */ int status; /* (return) non-ISO status */ -- cgit v1.2.3