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[libata] locking rewrite (== fix)

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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.
This commit is contained in:
Jeff Garzik
2005-10-30 23:31:48 -05:00
parent e533825447
commit 005a5a06a6
2 changed files with 8 additions and 3 deletions
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9
drivers/scsi/libata-scsi.c
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@@ -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 *cmd, void (*done)(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 *cmd, void (*done)(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;
}