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: 6c0cedd1ef952 ("mmc: core: Introduce host claiming by context")
Fixes: 1e8e55b67030c ("mmc: block: Add CQE support")
Cc: stable@vger.kernel.org
Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Penghe Geng <pgeng@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index e0e2c265e5d10100e1a54089a4c3f4fc4654d847..ba84f02c2a101e8e906a29bb3ddef2938d33626c 100644 (file)
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -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 */