Commit 901084c5 authored by Penghe Geng's avatar Penghe Geng Committed by Ulf Hansson
Browse files

mmc: core: Avoid bitfield RMW for claim/retune flags 



Move claimed and retune control flags out of the bitfield word to
avoid unrelated RMW side effects in asynchronous contexts.

The host->claimed bit shared a word with retune flags. Writes to claimed
in __mmc_claim_host() or retune_now in mmc_mq_queue_rq() can overwrite
other bits when concurrent updates happen in other contexts, triggering
spurious WARN_ON(!host->claimed). Convert claimed, can_retune,
retune_now and retune_paused to bool to remove shared-word coupling.

Fixes: 6c0cedd1 ("mmc: core: Introduce host claiming by context")
Fixes: 1e8e55b6 ("mmc: block: Add CQE support")
Cc: stable@vger.kernel.org
Suggested-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarPenghe Geng <pgeng@nvidia.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 79ad4715

include/linux/mmc/host.h

+5 −4
Original line number Diff line number Diff line
@@ -486,14 +486,12 @@ struct mmc_host { 


	struct mmc_ios		ios;		/* current io bus settings */



	bool			claimed;	/* host exclusively claimed */



	/* group bitfields together to minimize padding */

	unsigned int		use_spi_crc:1;

	unsigned int		claimed:1;	/* host exclusively claimed */

	unsigned int		doing_init_tune:1; /* initial tuning in progress */

	unsigned int		can_retune:1;	/* re-tuning can be used */

	unsigned int		doing_retune:1;	/* re-tuning in progress */

	unsigned int		retune_now:1;	/* do re-tuning at next req */

	unsigned int		retune_paused:1; /* re-tuning is temporarily disabled */

	unsigned int		retune_crc_disable:1; /* don't trigger retune upon crc */

	unsigned int		can_dma_map_merge:1; /* merging can be used */

	unsigned int		vqmmc_enabled:1; /* vqmmc regulator is enabled */
@@ -508,6 +506,9 @@ struct mmc_host { 
	int			rescan_disable;	/* disable card detection */

	int			rescan_entered;	/* used with nonremovable devices */



	bool			can_retune;	/* re-tuning can be used */

	bool			retune_now;	/* do re-tuning at next req */

	bool			retune_paused;	/* re-tuning is temporarily disabled */

	int			need_retune;	/* re-tuning is needed */

	int			hold_retune;	/* hold off re-tuning */

	unsigned int		retune_period;	/* re-tuning period in secs */