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author | Kevin Hao <haokexin@gmail.com> | 2014-07-12 04:08:24 (GMT) |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2014-07-14 16:38:20 (GMT) |
commit | 1871ee134b73fb4cadab75752a7152ed2813c751 (patch) | |
tree | 180fb7f61c21c9edafa9bf78f1cf7b5ec9cb0301 /drivers/ata/libata-core.c | |
parent | 7188b067576db95445bf4e9498f1bdb2e612dd2f (diff) | |
download | linux-1871ee134b73fb4cadab75752a7152ed2813c751.tar.xz |
libata: support the ata host which implements a queue depth less than 32
The sata on fsl mpc8315e is broken after the commit 8a4aeec8d2d6
("libata/ahci: accommodate tag ordered controllers"). The reason is
that the ata controller on this SoC only implement a queue depth of
16. When issuing the commands in tag order, all the commands in tag
16 ~ 31 are mapped to tag 0 unconditionally and then causes the sata
malfunction. It makes no senses to use a 32 queue in software while
the hardware has less queue depth. So consider the queue depth
implemented by the hardware when requesting a command tag.
Fixes: 8a4aeec8d2d6 ("libata/ahci: accommodate tag ordered controllers")
Cc: stable@vger.kernel.org
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'drivers/ata/libata-core.c')
-rw-r--r-- | drivers/ata/libata-core.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 18d97d5..d19c37a7 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -4787,6 +4787,10 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words) * ata_qc_new - Request an available ATA command, for queueing * @ap: target port * + * Some ATA host controllers may implement a queue depth which is less + * than ATA_MAX_QUEUE. So we shouldn't allocate a tag which is beyond + * the hardware limitation. + * * LOCKING: * None. */ @@ -4794,14 +4798,16 @@ 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; + unsigned int i, tag, max_queue; + + max_queue = ap->scsi_host->can_queue; /* no command while frozen */ if (unlikely(ap->pflags & ATA_PFLAG_FROZEN)) return NULL; - for (i = 0; i < ATA_MAX_QUEUE; i++) { - tag = (i + ap->last_tag + 1) % ATA_MAX_QUEUE; + for (i = 0, tag = ap->last_tag + 1; i < max_queue; i++, tag++) { + tag = tag < max_queue ? tag : 0; /* the last tag is reserved for internal command. */ if (tag == ATA_TAG_INTERNAL) @@ -6169,6 +6175,16 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht) { int i, rc; + /* + * 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 must have been started */ if (!(host->flags & ATA_HOST_STARTED)) { dev_err(host->dev, "BUG: trying to register unstarted host\n"); |