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Commit 70fedb7f authored by Asutosh Das's avatar Asutosh Das Committed by Matt Wagantall
Browse files

mmc: host: Fix spinbug in performance sysfs nodes 



In CMDQ, the mmc_release_host runs in softirq context.
There's a potential race condition between show/set_perf
since it doesn't disable pre-emption. Change this to
disable preemption.

Change-Id: I20918a459e8b35ac666971b8ebf179f44aa9c40f
Signed-off-by: default avatarAsutosh Das <asutoshd@codeaurora.org>
Signed-off-by: default avatarVenkat Gopalakrishnan <venkatg@codeaurora.org>
parent b5ce2d8c

drivers/mmc/core/host.c

+6 −5
Original line number Diff line number Diff line
@@ -698,9 +698,9 @@ show_perf(struct device *dev, struct device_attribute *attr, char *buf) 
{

	struct mmc_host *host = cls_dev_to_mmc_host(dev);

	int64_t rtime_drv, wtime_drv;

	unsigned long rbytes_drv, wbytes_drv;

	unsigned long rbytes_drv, wbytes_drv, flags;



	spin_lock(&host->lock);

	spin_lock_irqsave(&host->lock, flags);



	rbytes_drv = host->perf.rbytes_drv;

	wbytes_drv = host->perf.wbytes_drv;
@@ -708,7 +708,7 @@ show_perf(struct device *dev, struct device_attribute *attr, char *buf) 
	rtime_drv = ktime_to_us(host->perf.rtime_drv);

	wtime_drv = ktime_to_us(host->perf.wtime_drv);



	spin_unlock(&host->lock);

	spin_unlock_irqrestore(&host->lock, flags);



	return snprintf(buf, PAGE_SIZE, "Write performance at driver Level:"

					"%lu bytes in %lld microseconds\n"
@@ -724,16 +724,17 @@ set_perf(struct device *dev, struct device_attribute *attr, 
{

	struct mmc_host *host = cls_dev_to_mmc_host(dev);

	int64_t value;

	unsigned long flags;



	sscanf(buf, "%lld", &value);

	spin_lock(&host->lock);

	spin_lock_irqsave(&host->lock, flags);

	if (!value) {

		memset(&host->perf, 0, sizeof(host->perf));

		host->perf_enable = false;

	} else {

		host->perf_enable = true;

	}

	spin_unlock(&host->lock);

	spin_unlock_irqrestore(&host->lock, flags);



	return count;

}