during more testing it turned out that v1 was too optimistic w.r.t.devices serialization, v2 fixes it (so the patch can be finally mergedinto pata-2.6 tree)
From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>Subject: [PATCH] ide: use lock bitops for ports serialization (v2)
* Add ->host_busy field to struct ide_host and use it's first bit together with lock bitops to provide new ports serialization method.
* Convert core IDE code to use new ide_[un]lock_host() helpers.
This removes the need for taking hwgroup->lock if host is already busy on serialized hosts and makes it possible to merge ide_hwgroup_t into ide_hwif_t (done in the later patch).
* Remove no longer needed ide_hwgroup_t.busy and ide_[un]lock_hwgroup().
* Update do_ide_request() documentation.
v2:* ide_release_lock() should be called inside IDE_HFLAG_SERIALIZE check.
* Add ide_hwif_t.busy flag and ide_[un]lock_port() for serializing devices on a port.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>--- drivers/ide/ide-io.c | 105 ++++++++++++++++++++++++++++++--------------------- include/linux/ide.h | 35 ++--------------- 2 files changed, 69 insertions(+), 71 deletions(-)
Index: b/drivers/ide/ide-io.c===================================================================--- a/drivers/ide/ide-io.c+++ b/drivers/ide/ide-io.c@@ -666,45 +666,54 @@ void ide_stall_queue (ide_drive_t *drive } EXPORT_SYMBOL(ide_stall_queue); +static inline int ide_lock_port(ide_hwif_t *hwif)+{+ if (hwif->busy)+ return 1;++ hwif->busy = 1;++ return 0;+}++static inline void ide_unlock_port(ide_hwif_t *hwif)+{+ hwif->busy = 0;+}++static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)+{+ int rc = 0;++ if (host->host_flags & IDE_HFLAG_SERIALIZE) {+ rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);+ if (rc == 0) {+ /* for atari only */+ ide_get_lock(ide_intr, hwif);+ }+ }+ return rc;+}++static inline void ide_unlock_host(struct ide_host *host)+{+ if (host->host_flags & IDE_HFLAG_SERIALIZE) {+ /* for atari only */+ ide_release_lock();+ clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);+ }+}+ /* * Issue a new request to a drive from hwgroup- *- * A hwgroup is a serialized group of IDE interfaces. Usually there is- * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640)- * may have both interfaces in a single hwgroup to "serialize" access.- * Or possibly multiple ISA interfaces can share a common IRQ by being grouped- * together into one hwgroup for serialized access.- *- * Note also that several hwgroups can end up sharing a single IRQ,- * possibly along with many other devices. This is especially common in- * PCI-based systems with off-board IDE controller cards.- *- * The IDE driver uses a per-hwgroup lock to protect the hwgroup->busy flag.- *- * The first thread into the driver for a particular hwgroup sets the- * hwgroup->busy flag to indicate that this hwgroup is now active,- * and then initiates processing of the top request from the request queue.- *- * Other threads attempting entry notice the busy setting, and will simply- * queue their new requests and exit immediately. Note that hwgroup->busy- * remains set even when the driver is merely awaiting the next interrupt.- * Thus, the meaning is "this hwgroup is busy processing a request".- *- * When processing of a request completes, the completing thread or IRQ-handler- * will start the next request from the queue. If no more work remains,- * the driver will clear the hwgroup->busy flag and exit.- *- * The per-hwgroup spinlock is used to protect all access to the- * hwgroup->busy flag, but is otherwise not needed for most processing in- * the driver. This makes the driver much more friendlier to shared IRQs- * than previous designs, while remaining 100% (?) SMP safe and capable. */ void do_ide_request(struct request_queue *q) { ide_drive_t *drive = q->queuedata; ide_hwif_t *hwif = drive->hwif;+ struct ide_host *host = hwif->host; ide_hwgroup_t *hwgroup = hwif->hwgroup;- struct request *rq;+ struct request *rq = NULL; ide_startstop_t startstop; /*@@ -721,9 +730,13 @@ void do_ide_request(struct request_queue blk_remove_plug(q); spin_unlock_irq(q->queue_lock);++ if (ide_lock_host(host, hwif))+ goto plug_device_2;+ spin_lock_irq(&hwgroup->lock); - if (!ide_lock_hwgroup(hwgroup, hwif)) {+ if (!ide_lock_port(hwif)) { ide_hwif_t *prev_port; repeat: prev_port = hwif->host->cur_port;@@ -731,7 +744,7 @@ repeat: if (drive->dev_flags & IDE_DFLAG_SLEEPING) { if (time_before(drive->sleep, jiffies)) {- ide_unlock_hwgroup(hwgroup);+ ide_unlock_port(hwif); goto plug_device; } }@@ -761,7 +774,7 @@ repeat: spin_lock_irq(&hwgroup->lock); if (!rq) {- ide_unlock_hwgroup(hwgroup);+ ide_unlock_port(hwif); goto out; } @@ -782,7 +795,7 @@ repeat: blk_pm_request(rq) == 0 && (rq->cmd_flags & REQ_PREEMPT) == 0) { /* there should be no pending command at this point */- ide_unlock_hwgroup(hwgroup);+ ide_unlock_port(hwif); goto plug_device; } @@ -798,11 +811,15 @@ repeat: goto plug_device; out: spin_unlock_irq(&hwgroup->lock);+ if (rq == NULL)+ ide_unlock_host(host); spin_lock_irq(q->queue_lock); return; plug_device: spin_unlock_irq(&hwgroup->lock);+ ide_unlock_host(host);+plug_device_2: spin_lock_irq(q->queue_lock); if (!elv_queue_empty(q))@@ -844,9 +861,9 @@ static ide_startstop_t ide_dma_timeout_r ide_dma_off_quietly(drive); /*- * un-busy drive etc (hwgroup->busy is cleared on return) and- * make sure request is sane+ * un-busy drive etc and make sure request is sane */+ rq = HWGROUP(drive)->rq; if (!rq)@@ -895,6 +912,7 @@ static void ide_plug_device(ide_drive_t void ide_timer_expiry (unsigned long data) { ide_hwgroup_t *hwgroup = (ide_hwgroup_t *) data;+ ide_hwif_t *uninitialized_var(hwif); ide_drive_t *uninitialized_var(drive); ide_handler_t *handler; ide_expiry_t *expiry;@@ -918,7 +936,6 @@ void ide_timer_expiry (unsigned long dat printk(KERN_ERR "%s: ->cur_dev was NULL\n", __func__); hwgroup->handler = NULL; } else {- ide_hwif_t *hwif; ide_startstop_t startstop = ide_stopped; if ((expiry = hwgroup->expiry) != NULL) {@@ -964,15 +981,17 @@ void ide_timer_expiry (unsigned long dat spin_lock_irq(&hwgroup->lock); enable_irq(hwif->irq); if (startstop == ide_stopped) {- ide_unlock_hwgroup(hwgroup);+ ide_unlock_port(hwif); plug_device = 1; } } } spin_unlock_irqrestore(&hwgroup->lock, flags); - if (plug_device)+ if (plug_device) {+ ide_unlock_host(hwif->host); ide_plug_device(drive);+ } } /**@@ -1150,7 +1169,7 @@ irqreturn_t ide_intr (int irq, void *dev */ if (startstop == ide_stopped) { if (hwgroup->handler == NULL) { /* paranoia */- ide_unlock_hwgroup(hwgroup);+ ide_unlock_port(hwif); plug_device = 1; } else printk(KERN_ERR "%s: %s: huh? expected NULL handler "@@ -1161,8 +1180,10 @@ out_handled: out: spin_unlock_irqrestore(&hwgroup->lock, flags); out_early:- if (plug_device)+ if (plug_device) {+ ide_unlock_host(hwif->host); ide_plug_device(drive);+ } return irq_ret; }Index: b/include/linux/ide.h===================================================================--- a/include/linux/ide.h+++ b/include/linux/ide.h@@ -828,6 +828,7 @@ typedef struct hwif_s { unsigned present : 1; /* this interface exists */ unsigned sg_mapped : 1; /* sg_table and sg_nents are ready */+ unsigned busy : 1; /* serializes devices on a port */ struct device gendev; struct device *portdev;@@ -851,8 +852,13 @@ struct ide_host { unsigned long host_flags; void *host_priv; ide_hwif_t *cur_port; /* for hosts requiring serialization */++ /* used for hosts requiring serialization */+ volatile long host_busy; }; +#define IDE_HOST_BUSY 0+ /* * internal ide interrupt handler type */@@ -866,8 +872,6 @@ typedef struct hwgroup_s { /* irq handler, if active */ ide_startstop_t (*handler)(ide_drive_t *); - /* BOOL: protects all fields below */- volatile int busy; /* BOOL: polling active & poll_timeout field valid */ unsigned int polling : 1; @@ -1271,26 +1275,6 @@ extern void ide_stall_queue(ide_drive_t extern void ide_timer_expiry(unsigned long); extern irqreturn_t ide_intr(int irq, void *dev_id);--static inline int ide_lock_hwgroup(ide_hwgroup_t *hwgroup, ide_hwif_t *hwif)-{- if (hwgroup->busy)- return 1;-- hwgroup->busy = 1;- /* for atari only */- ide_get_lock(ide_intr, hwif);-- return 0;-}--static inline void ide_unlock_hwgroup(ide_hwgroup_t *hwgroup)-{- /* for atari only */- ide_release_lock();- hwgroup->busy = 0;-}- extern void do_ide_request(struct request_queue *); void ide_init_disk(struct gendisk *, ide_drive_t *);@@ -1617,13 +1601,6 @@ static inline void ide_set_max_pio(ide_d extern spinlock_t ide_lock; extern struct mutex ide_cfg_mtx;-/*- * Structure locking:- *- * ide_hwgroup_t->busy: hwgroup->lock- * ide_hwif_t->{hwgroup,mate}: constant, no locking- * ide_drive_t->hwif: constant, no locking- */ #define local_irq_set(flags) do { local_save_flags((flags)); local_irq_enable_in_hardirq(); } while (0) ÿôèº{.nÇ+?·?®??+%?Ëÿ±éݶ¥?wÿº{.nÇ+?·¥?{±þ'^þ)í?æèw* jg¬±¨ ¶????Ý¢jÿ¾«þG«?éÿ¢¸ ¢·¦j:+v?¨?wèjØm¶?ÿþø ¯ù ®w¥þ?àþf£¢·h??â?úÿ?Ù¥
