mmc: prohibit card detection when host is not ready (d9adcc12) · Commits · 戴 / test

Currently mmc host drivers have to decide whether to enable card detection before calling mmc_add_host() -- in which case a card insertion event can arrive before the host has been completely initialised -- or after mmc_add_host(), in which case the initial card detection can be problematic. This patch adds an explicit indication of when card detection should not be carried out. With it in place enabling card detection before calling mmc_add_host() should be safe. Similarly, disabling it again after calling mmc_remove_host() will avoid any races. Signed-off-by:

Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by:

Chris Ball <cjb@laptop.org>

drivers/mmc/core/core.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -2107,6 +2107,7 @@ void mmc_rescan(struct work_struct *work)
		void mmc_start_host(struct mmc_host *host)
		{
		host->f_init = max(freqs[0], host->f_min);
		host->rescan_disable = 0;
		mmc_power_up(host);
		mmc_detect_change(host, 0);
		}
		@@ -2120,6 +2121,7 @@ void mmc_stop_host(struct mmc_host *host)
		spin_unlock_irqrestore(&host->lock, flags);
		#endif

		host->rescan_disable = 1;
		cancel_delayed_work_sync(&host->detect);
		mmc_flush_scheduled_work();

drivers/mmc/core/host.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -313,6 +313,8 @@ struct mmc_host mmc_alloc_host(int extra, struct device dev)
		if (!host)
		return NULL;

		/* scanning will be enabled when we're ready */
		host->rescan_disable = 1;
		spin_lock(&mmc_host_lock);
		err = idr_get_new(&mmc_host_idr, host, &host->index);
		spin_unlock(&mmc_host_lock);

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