From f69499f42caf74194df678c9c293f2ee0fe90bc3 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 15 May 2006 20:58:03 +0900 Subject: [PATCH] [PATCH] libata-eh-fw: update ata_qc_from_tag() to enforce normal/EH qc ownership New EH framework has clear distinction about who owns a qc. Every qc starts owned by normal execution path - PIO, interrupt or whatever. When an exception condition occurs which affects the qc, the qc gets scheduled for EH. Note that some events (say, link lost and regained, command timeout) may schedule qc's which are not directly related but could have been affected for EH too. Scheduling for EH is atomic w.r.t. ap->host_set->lock and once schedule for EH, normal execution path is not allowed to access the qc in whatever way. (PIO synchronization acts a bit different and will be dealt with later) This patch make ata_qc_from_tag() check whether a qc is active and owned by normal path before returning it. If conditions don't match, NULL is returned and thus access to the qc is denied. __ata_qc_from_tag() is the original ata_qc_from_tag() and is used by libata core/EH layers to access inactive/failed qc's. This change is applied only if the associated LLDD implements new EH as indicated by non-NULL ->error_handler Signed-off-by: Tejun Heo --- drivers/scsi/libata-core.c | 4 ++-- include/linux/libata.h | 19 +++++++++++++++++-- 2 files changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index 966abb5f423e..1c34c1427aa3 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -1001,7 +1001,7 @@ unsigned ata_exec_internal(struct ata_device *dev, if (test_and_set_bit(tag, &ap->qactive)) BUG(); - qc = ata_qc_from_tag(ap, tag); + qc = __ata_qc_from_tag(ap, tag); qc->tag = tag; qc->scsicmd = NULL; @@ -4042,7 +4042,7 @@ static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap) /* the last tag is reserved for internal command. */ for (i = 0; i < ATA_MAX_QUEUE - 1; i++) if (!test_and_set_bit(i, &ap->qactive)) { - qc = ata_qc_from_tag(ap, i); + qc = __ata_qc_from_tag(ap, i); break; } diff --git a/include/linux/libata.h b/include/linux/libata.h index 5a403e434ff8..bfcefdca0616 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -832,14 +832,29 @@ static inline void ata_qc_set_polling(struct ata_queued_cmd *qc) qc->tf.ctl |= ATA_NIEN; } -static inline struct ata_queued_cmd *ata_qc_from_tag (struct ata_port *ap, - unsigned int tag) +static inline struct ata_queued_cmd *__ata_qc_from_tag(struct ata_port *ap, + unsigned int tag) { if (likely(ata_tag_valid(tag))) return &ap->qcmd[tag]; return NULL; } +static inline struct ata_queued_cmd *ata_qc_from_tag(struct ata_port *ap, + unsigned int tag) +{ + struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag); + + if (unlikely(!qc) || !ap->ops->error_handler) + return qc; + + if ((qc->flags & (ATA_QCFLAG_ACTIVE | + ATA_QCFLAG_FAILED)) == ATA_QCFLAG_ACTIVE) + return qc; + + return NULL; +} + static inline void ata_tf_init(struct ata_device *dev, struct ata_taskfile *tf) { memset(tf, 0, sizeof(*tf)); -- 2.30.2