Re: [PATCH 2/2] libata: Fix NULL pointer of scsi_host in ata_port

From: Tejun Heo
Date: Tue Jul 22 2014 - 16:11:21 EST


Hello,

Can you please test the following patch?

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index d19c37a7..773f4e6 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4798,9 +4798,8 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
{
struct ata_queued_cmd *qc = NULL;
- unsigned int i, tag, max_queue;
-
- max_queue = ap->scsi_host->can_queue;
+ unsigned int max_queue = ap->host->n_tags;
+ unsigned int i, tag;

/* no command while frozen */
if (unlikely(ap->pflags & ATA_PFLAG_FROZEN))
@@ -6094,6 +6093,7 @@ void ata_host_init(struct ata_host *host, struct device *dev,
{
spin_lock_init(&host->lock);
mutex_init(&host->eh_mutex);
+ host->n_tags = ATA_MAX_QUEUE;
host->dev = dev;
host->ops = ops;
}
@@ -6179,11 +6179,7 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
* The max queue supported by hardware must not be greater than
* ATA_MAX_QUEUE.
*/
- if (sht->can_queue > ATA_MAX_QUEUE) {
- dev_err(host->dev, "BUG: the hardware max queue is too large\n");
- WARN_ON(1);
- return -EINVAL;
- }
+ host->n_tags = clamp(sht->can_queue, 1, ATA_MAX_QUEUE);

/* host must have been started */
if (!(host->flags & ATA_HOST_STARTED)) {
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 5ab4e3a..92abb49 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -593,6 +593,7 @@ struct ata_host {
struct device *dev;
void __iomem * const *iomap;
unsigned int n_ports;
+ unsigned int n_tags; /* nr of NCQ tags */
void *private_data;
struct ata_port_operations *ops;
unsigned long flags;
--
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