[git patches] 2.6.x libata fixes, cleanup
From: Jeff Garzik
Date: Mon Oct 31 2005 - 09:29:06 EST
Please pull from 'upstream-linus' branch of
master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/libata-dev.git
to obtain the following locking rewrite (deadlock fix), and minor cleanups.
drivers/scsi/libata-core.c | 59 +++++++--------------------------------------
drivers/scsi/libata-scsi.c | 9 ++++++
drivers/scsi/libata.h | 1
3 files changed, 18 insertions(+), 51 deletions(-)
commit 005a5a06a6dd13a0ca3f2c6a0218e8d94ed36d8a
Author: Jeff Garzik <jgarzik@xxxxxxxxx>
Date: Sun Oct 30 23:31:48 2005 -0500
[libata] locking rewrite (== fix)
A lot of power packed into a little patch.
This change eliminates the sharing between our controller-wide spinlock
and the SCSI core's Scsi_Host lock. As the locking in libata was
already highly compartmentalized, always referencing our own lock, and
never scsi_host::host_lock.
As a side effect, this change eliminates a deadlock from calling
scsi_finish_command() while inside our spinlock.
commit e533825447dcb60a82b7cc9d73d06423c849b9a2
Author: Jeff Garzik <jgarzik@xxxxxxxxx>
Date: Sun Oct 30 21:37:17 2005 -0500
[libata] ata_tf_to_host cleanups
Integrate ata_exec() and ata_tf_to_host() into their only caller,
ata_bus_edd().
Rename ata_tf_to_host_nolock() to ata_tf_to_host().
This makes locking a bit easier to review, and may help pave the way for
future changes.
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 8be7dc0..ff18fa7 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -295,28 +295,6 @@ void ata_exec_command(struct ata_port *a
}
/**
- * ata_exec - issue ATA command to host controller
- * @ap: port to which command is being issued
- * @tf: ATA taskfile register set
- *
- * Issues PIO/MMIO write to ATA command register, with proper
- * synchronization with interrupt handler / other threads.
- *
- * LOCKING:
- * Obtains host_set lock.
- */
-
-static inline void ata_exec(struct ata_port *ap, const struct ata_taskfile *tf)
-{
- unsigned long flags;
-
- DPRINTK("ata%u: cmd 0x%X\n", ap->id, tf->command);
- spin_lock_irqsave(&ap->host_set->lock, flags);
- ap->ops->exec_command(ap, tf);
- spin_unlock_irqrestore(&ap->host_set->lock, flags);
-}
-
-/**
* ata_tf_to_host - issue ATA taskfile to host controller
* @ap: port to which command is being issued
* @tf: ATA taskfile register set
@@ -326,30 +304,11 @@ static inline void ata_exec(struct ata_p
* other threads.
*
* LOCKING:
- * Obtains host_set lock.
- */
-
-static void ata_tf_to_host(struct ata_port *ap, const struct ata_taskfile *tf)
-{
- ap->ops->tf_load(ap, tf);
-
- ata_exec(ap, tf);
-}
-
-/**
- * ata_tf_to_host_nolock - issue ATA taskfile to host controller
- * @ap: port to which command is being issued
- * @tf: ATA taskfile register set
- *
- * Issues ATA taskfile register set to ATA host controller,
- * with proper synchronization with interrupt handler and
- * other threads.
- *
- * LOCKING:
* spin_lock_irqsave(host_set lock)
*/
-void ata_tf_to_host_nolock(struct ata_port *ap, const struct ata_taskfile *tf)
+static inline void ata_tf_to_host(struct ata_port *ap,
+ const struct ata_taskfile *tf)
{
ap->ops->tf_load(ap, tf);
ap->ops->exec_command(ap, tf);
@@ -1912,12 +1871,14 @@ static void ata_bus_post_reset(struct at
*
* LOCKING:
* PCI/etc. bus probe sem.
+ * Obtains host_set lock.
*
*/
static unsigned int ata_bus_edd(struct ata_port *ap)
{
struct ata_taskfile tf;
+ unsigned long flags;
/* set up execute-device-diag (bus reset) taskfile */
/* also, take interrupts to a known state (disabled) */
@@ -1928,7 +1889,9 @@ static unsigned int ata_bus_edd(struct a
tf.protocol = ATA_PROT_NODATA;
/* do bus reset */
+ spin_lock_irqsave(&ap->host_set->lock, flags);
ata_tf_to_host(ap, &tf);
+ spin_unlock_irqrestore(&ap->host_set->lock, flags);
/* spec says at least 2ms. but who knows with those
* crazy ATAPI devices...
@@ -3555,7 +3518,7 @@ int ata_qc_issue_prot(struct ata_queued_
switch (qc->tf.protocol) {
case ATA_PROT_NODATA:
- ata_tf_to_host_nolock(ap, &qc->tf);
+ ata_tf_to_host(ap, &qc->tf);
break;
case ATA_PROT_DMA:
@@ -3566,20 +3529,20 @@ int ata_qc_issue_prot(struct ata_queued_
case ATA_PROT_PIO: /* load tf registers, initiate polling pio */
ata_qc_set_polling(qc);
- ata_tf_to_host_nolock(ap, &qc->tf);
+ ata_tf_to_host(ap, &qc->tf);
ap->hsm_task_state = HSM_ST;
queue_work(ata_wq, &ap->pio_task);
break;
case ATA_PROT_ATAPI:
ata_qc_set_polling(qc);
- ata_tf_to_host_nolock(ap, &qc->tf);
+ ata_tf_to_host(ap, &qc->tf);
queue_work(ata_wq, &ap->packet_task);
break;
case ATA_PROT_ATAPI_NODATA:
ap->flags |= ATA_FLAG_NOINTR;
- ata_tf_to_host_nolock(ap, &qc->tf);
+ ata_tf_to_host(ap, &qc->tf);
queue_work(ata_wq, &ap->packet_task);
break;
@@ -4126,8 +4089,6 @@ static void ata_host_init(struct ata_por
host->unique_id = ata_unique_id++;
host->max_cmd_len = 12;
- scsi_assign_lock(host, &host_set->lock);
-
ap->flags = ATA_FLAG_PORT_DISABLED;
ap->id = host->unique_id;
ap->host = host;
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 1e3792f..248baae 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -39,6 +39,7 @@
#include <scsi/scsi.h>
#include "scsi.h"
#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
#include <linux/libata.h>
#include <linux/hdreg.h>
#include <asm/uaccess.h>
@@ -2405,8 +2406,12 @@ int ata_scsi_queuecmd(struct scsi_cmnd *
struct ata_port *ap;
struct ata_device *dev;
struct scsi_device *scsidev = cmd->device;
+ struct Scsi_Host *shost = scsidev->host;
- ap = (struct ata_port *) &scsidev->host->hostdata[0];
+ ap = (struct ata_port *) &shost->hostdata[0];
+
+ spin_unlock(shost->host_lock);
+ spin_lock(&ap->host_set->lock);
ata_scsi_dump_cdb(ap, cmd);
@@ -2429,6 +2434,8 @@ int ata_scsi_queuecmd(struct scsi_cmnd *
ata_scsi_translate(ap, dev, cmd, done, atapi_xlat);
out_unlock:
+ spin_unlock(&ap->host_set->lock);
+ spin_lock(shost->host_lock);
return 0;
}
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index 10ecd9e..fad051c 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -48,7 +48,6 @@ extern int ata_qc_issue(struct ata_queue
extern int ata_check_atapi_dma(struct ata_queued_cmd *qc);
extern void ata_dev_select(struct ata_port *ap, unsigned int device,
unsigned int wait, unsigned int can_sleep);
-extern void ata_tf_to_host_nolock(struct ata_port *ap, const struct ata_taskfile *tf);
extern void swap_buf_le16(u16 *buf, unsigned int buf_words);
extern int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg);
extern int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg);
-
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