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[SCSI] Revert "sg: push file descriptor list locking down to per-device locking"
This reverts commit 1f962ebcdf.
This is one of four patches that was causing this bug
[ 205.372823] ================================================
[ 205.372901] [ BUG: lock held when returning to user space! ]
[ 205.372979] 3.12.0-rc6-hw-debug-pagealloc+ #67 Not tainted
[ 205.373055] ------------------------------------------------
[ 205.373132] megarc.bin/5283 is leaving the kernel with locks still held!
[ 205.373212] 1 lock held by megarc.bin/5283:
[ 205.373285] #0: (&sdp->o_sem){.+.+..}, at: [<ffffffff8161e650>] sg_open+0x3a0/0x4d0
Cc: Vaughan Cao <vaughan.cao@oracle.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
James Bottomley
parent
10c580e423
commit
c0d3b9c29e
@ -106,7 +106,8 @@ static int sg_add(struct device *, struct class_interface *);
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static void sg_remove(struct device *, struct class_interface *);
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static DEFINE_IDR(sg_index_idr);
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static DEFINE_RWLOCK(sg_index_lock);
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static DEFINE_RWLOCK(sg_index_lock); /* Also used to lock
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file descriptor list for device */
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static struct class_interface sg_interface = {
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.add_dev = sg_add,
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@ -143,7 +144,8 @@ typedef struct sg_request { /* SG_MAX_QUEUE requests outstanding per file */
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} Sg_request;
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typedef struct sg_fd { /* holds the state of a file descriptor */
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struct list_head sfd_siblings; /* protected by sfd_lock of device */
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/* sfd_siblings is protected by sg_index_lock */
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struct list_head sfd_siblings;
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struct sg_device *parentdp; /* owning device */
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wait_queue_head_t read_wait; /* queue read until command done */
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rwlock_t rq_list_lock; /* protect access to list in req_arr */
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@ -168,7 +170,7 @@ typedef struct sg_device { /* holds the state of each scsi generic device */
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struct scsi_device *device;
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int sg_tablesize; /* adapter's max scatter-gather table size */
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u32 index; /* device index number */
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spinlock_t sfd_lock; /* protect file descriptor list for device */
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/* sfds is protected by sg_index_lock */
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struct list_head sfds;
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struct rw_semaphore o_sem; /* exclude open should hold this rwsem */
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volatile char detached; /* 0->attached, 1->detached pending removal */
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@ -225,9 +227,9 @@ static int sfds_list_empty(Sg_device *sdp)
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unsigned long flags;
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int ret;
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spin_lock_irqsave(&sdp->sfd_lock, flags);
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read_lock_irqsave(&sg_index_lock, flags);
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ret = list_empty(&sdp->sfds);
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spin_unlock_irqrestore(&sdp->sfd_lock, flags);
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read_unlock_irqrestore(&sg_index_lock, flags);
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return ret;
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}
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@ -1391,7 +1393,6 @@ static Sg_device *sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
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disk->first_minor = k;
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sdp->disk = disk;
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sdp->device = scsidp;
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spin_lock_init(&sdp->sfd_lock);
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INIT_LIST_HEAD(&sdp->sfds);
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init_rwsem(&sdp->o_sem);
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sdp->sg_tablesize = queue_max_segments(q);
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@ -1526,13 +1527,11 @@ static void sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
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/* Need a write lock to set sdp->detached. */
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write_lock_irqsave(&sg_index_lock, iflags);
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spin_lock(&sdp->sfd_lock);
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sdp->detached = 1;
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list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
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wake_up_interruptible(&sfp->read_wait);
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kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
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}
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spin_unlock(&sdp->sfd_lock);
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write_unlock_irqrestore(&sg_index_lock, iflags);
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sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
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@ -2057,13 +2056,13 @@ sg_add_sfp(Sg_device * sdp, int dev)
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sfp->cmd_q = SG_DEF_COMMAND_Q;
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sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
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sfp->parentdp = sdp;
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spin_lock_irqsave(&sdp->sfd_lock, iflags);
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write_lock_irqsave(&sg_index_lock, iflags);
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if (sdp->detached) {
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spin_unlock_irqrestore(&sdp->sfd_lock, iflags);
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write_unlock_irqrestore(&sg_index_lock, iflags);
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return ERR_PTR(-ENODEV);
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}
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list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
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spin_unlock_irqrestore(&sdp->sfd_lock, iflags);
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write_unlock_irqrestore(&sg_index_lock, iflags);
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SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
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if (unlikely(sg_big_buff != def_reserved_size))
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sg_big_buff = def_reserved_size;
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@ -2110,12 +2109,11 @@ static void sg_remove_sfp_usercontext(struct work_struct *work)
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static void sg_remove_sfp(struct kref *kref)
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{
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struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
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struct sg_device *sdp = sfp->parentdp;
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unsigned long iflags;
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spin_lock_irqsave(&sdp->sfd_lock, iflags);
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write_lock_irqsave(&sg_index_lock, iflags);
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list_del(&sfp->sfd_siblings);
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spin_unlock_irqrestore(&sdp->sfd_lock, iflags);
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write_unlock_irqrestore(&sg_index_lock, iflags);
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INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
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schedule_work(&sfp->ew.work);
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@ -2502,7 +2500,7 @@ static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
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return 0;
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}
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/* must be called while holding sg_index_lock and sfd_lock */
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/* must be called while holding sg_index_lock */
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static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
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{
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int k, m, new_interface, blen, usg;
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@ -2587,26 +2585,22 @@ static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
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read_lock_irqsave(&sg_index_lock, iflags);
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sdp = it ? sg_lookup_dev(it->index) : NULL;
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if (sdp) {
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spin_lock(&sdp->sfd_lock);
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if (!list_empty(&sdp->sfds)) {
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struct scsi_device *scsidp = sdp->device;
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if (sdp && !list_empty(&sdp->sfds)) {
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struct scsi_device *scsidp = sdp->device;
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seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
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if (sdp->detached)
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seq_printf(s, "detached pending close ");
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else
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seq_printf
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(s, "scsi%d chan=%d id=%d lun=%d em=%d",
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scsidp->host->host_no,
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scsidp->channel, scsidp->id,
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scsidp->lun,
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scsidp->host->hostt->emulated);
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seq_printf(s, " sg_tablesize=%d excl=%d\n",
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sdp->sg_tablesize, sdp->exclude);
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sg_proc_debug_helper(s, sdp);
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}
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spin_unlock(&sdp->sfd_lock);
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seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
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if (sdp->detached)
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seq_printf(s, "detached pending close ");
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else
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seq_printf
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(s, "scsi%d chan=%d id=%d lun=%d em=%d",
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scsidp->host->host_no,
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scsidp->channel, scsidp->id,
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scsidp->lun,
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scsidp->host->hostt->emulated);
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seq_printf(s, " sg_tablesize=%d excl=%d\n",
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sdp->sg_tablesize, sdp->exclude);
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sg_proc_debug_helper(s, sdp);
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}
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read_unlock_irqrestore(&sg_index_lock, iflags);
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return 0;
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