From c62b17a58ab5e97534ff6487241addd5fcc606de Mon Sep 17 00:00:00 2001 From: Romit Dasgupta Date: Thu, 12 Nov 2009 13:08:11 +0100 Subject: [PATCH 1/2] Thaw refrigerated bdi flusher threads before invoking kthread_stop on them Unfreezes the bdi flusher task when the said task needs to exit. Steps to reproduce this. 1) Mount a file system from MMC/SD card. 2) Unmount the file system. This creates a flusher task. 3) Attempt suspend to RAM. System is unresponsive. This is because the bdi flusher thread is already in the refrigerator and will remain so until it is thawed. The MMC driver suspend routine call stack will ultimately issue a 'kthread_stop' on the bdi flusher thread and will block until the flusher thread is exited. Since the bdi flusher thread is in the refrigerator it never cleans up until thawed. Signed-off-by: Romit Dasgupta Signed-off-by: Jens Axboe --- mm/backing-dev.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 11aee09dd2a6..67a33a5a1a93 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -604,10 +604,14 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi) /* * Finally, kill the kernel threads. We don't need to be RCU - * safe anymore, since the bdi is gone from visibility. + * safe anymore, since the bdi is gone from visibility. Force + * unfreeze of the thread before calling kthread_stop(), otherwise + * it would never exet if it is currently stuck in the refrigerator. */ - list_for_each_entry(wb, &bdi->wb_list, list) + list_for_each_entry(wb, &bdi->wb_list, list) { + wb->task->flags &= ~PF_FROZEN; kthread_stop(wb->task); + } } /* From 69ac74822277fa999a3f469d8362e93262deb3f4 Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Fri, 13 Nov 2009 08:47:53 +0100 Subject: [PATCH 2/2] cciss: make device attrs static No need to export those device attributes. In fact, without this patch, we can trip over a build error if cciss is a built-in and another driver also declares and exports attributes with the same name. You'll see errors like: drivers/scsi/built-in.o: multiple definition of `dev_attr_lunid' drivers/block/built-in.o: first defined here Cc: Stephen M. Cameron Signed-off-by: Alex Chiang Cc: Cc: Jens Axboe Signed-off-by: Jens Axboe --- drivers/block/cciss.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c index 6399e5090df4..92b126394fa1 100644 --- a/drivers/block/cciss.c +++ b/drivers/block/cciss.c @@ -482,7 +482,7 @@ static ssize_t host_store_rescan(struct device *dev, return count; } -DEVICE_ATTR(rescan, S_IWUSR, NULL, host_store_rescan); +static DEVICE_ATTR(rescan, S_IWUSR, NULL, host_store_rescan); static ssize_t dev_show_unique_id(struct device *dev, struct device_attribute *attr, @@ -512,7 +512,7 @@ static ssize_t dev_show_unique_id(struct device *dev, sn[8], sn[9], sn[10], sn[11], sn[12], sn[13], sn[14], sn[15]); } -DEVICE_ATTR(unique_id, S_IRUGO, dev_show_unique_id, NULL); +static DEVICE_ATTR(unique_id, S_IRUGO, dev_show_unique_id, NULL); static ssize_t dev_show_vendor(struct device *dev, struct device_attribute *attr, @@ -536,7 +536,7 @@ static ssize_t dev_show_vendor(struct device *dev, else return snprintf(buf, sizeof(vendor) + 1, "%s\n", drv->vendor); } -DEVICE_ATTR(vendor, S_IRUGO, dev_show_vendor, NULL); +static DEVICE_ATTR(vendor, S_IRUGO, dev_show_vendor, NULL); static ssize_t dev_show_model(struct device *dev, struct device_attribute *attr, @@ -560,7 +560,7 @@ static ssize_t dev_show_model(struct device *dev, else return snprintf(buf, sizeof(model) + 1, "%s\n", drv->model); } -DEVICE_ATTR(model, S_IRUGO, dev_show_model, NULL); +static DEVICE_ATTR(model, S_IRUGO, dev_show_model, NULL); static ssize_t dev_show_rev(struct device *dev, struct device_attribute *attr, @@ -584,7 +584,7 @@ static ssize_t dev_show_rev(struct device *dev, else return snprintf(buf, sizeof(rev) + 1, "%s\n", drv->rev); } -DEVICE_ATTR(rev, S_IRUGO, dev_show_rev, NULL); +static DEVICE_ATTR(rev, S_IRUGO, dev_show_rev, NULL); static ssize_t cciss_show_lunid(struct device *dev, struct device_attribute *attr, char *buf) @@ -609,7 +609,7 @@ static ssize_t cciss_show_lunid(struct device *dev, lunid[0], lunid[1], lunid[2], lunid[3], lunid[4], lunid[5], lunid[6], lunid[7]); } -DEVICE_ATTR(lunid, S_IRUGO, cciss_show_lunid, NULL); +static DEVICE_ATTR(lunid, S_IRUGO, cciss_show_lunid, NULL); static ssize_t cciss_show_raid_level(struct device *dev, struct device_attribute *attr, char *buf) @@ -632,7 +632,7 @@ static ssize_t cciss_show_raid_level(struct device *dev, return snprintf(buf, strlen(raid_label[raid]) + 7, "RAID %s\n", raid_label[raid]); } -DEVICE_ATTR(raid_level, S_IRUGO, cciss_show_raid_level, NULL); +static DEVICE_ATTR(raid_level, S_IRUGO, cciss_show_raid_level, NULL); static ssize_t cciss_show_usage_count(struct device *dev, struct device_attribute *attr, char *buf) @@ -651,7 +651,7 @@ static ssize_t cciss_show_usage_count(struct device *dev, spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags); return snprintf(buf, 20, "%d\n", count); } -DEVICE_ATTR(usage_count, S_IRUGO, cciss_show_usage_count, NULL); +static DEVICE_ATTR(usage_count, S_IRUGO, cciss_show_usage_count, NULL); static struct attribute *cciss_host_attrs[] = { &dev_attr_rescan.attr,