From 005a5a06a6dd13a0ca3f2c6a0218e8d94ed36d8a Mon Sep 17 00:00:00 2001 From: Jeff Garzik <jgarzik@pobox.com> Date: Sun, 30 Oct 2005 23:31:48 -0500 Subject: [PATCH] [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. --- drivers/scsi/libata-core.c | 2 -- drivers/scsi/libata-scsi.c | 9 ++++++++- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index a17e12032f65..ff18fa7044c5 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -4089,8 +4089,6 @@ static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host, 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 1e3792f86fcf..248baae96486 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 *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; }