diff options
Diffstat (limited to 'include/os/linux/kernel/linux/blkdev_compat.h')
| -rw-r--r-- | include/os/linux/kernel/linux/blkdev_compat.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/include/os/linux/kernel/linux/blkdev_compat.h b/include/os/linux/kernel/linux/blkdev_compat.h index b0f398354e4f..658f546213de 100644 --- a/include/os/linux/kernel/linux/blkdev_compat.h +++ b/include/os/linux/kernel/linux/blkdev_compat.h @@ -94,6 +94,33 @@ blk_queue_set_write_cache(struct request_queue *q, bool wc, bool fua) #endif } +/* + * Detect if a device has a write cache. Used to set the intial value for the + * vdev nowritecache flag. + * + * 4.10: QUEUE_FLAG_WC added. Initialised by the driver, but can be changed + * later by the operator. If not set, kernel will return flush requests + * immediately without doing anything. + * 6.6: QUEUE_FLAG_HW_WC added. Initialised by the driver, can't be changed. + * Only controls if the operator is allowed to change _WC. Initial version + * buggy; aliased to QUEUE_FLAG_FUA, so unuseable. + * 6.6.10, 6.7: QUEUE_FLAG_HW_WC fixed. + * + * Older than 4.10 we just assume write cache, and let the normal flush fail + * detection apply. + */ +static inline boolean_t +zfs_bdev_has_write_cache(struct block_device *bdev) +{ +#if defined(QUEUE_FLAG_HW_WC) && QUEUE_FLAG_HW_WC != QUEUE_FLAG_FUA + return (test_bit(QUEUE_FLAG_HW_WC, &bdev_get_queue(bdev)->queue_flags)); +#elif defined(QUEUE_FLAG_WC) + return (test_bit(QUEUE_FLAG_WC, &bdev_get_queue(bdev)->queue_flags)); +#else + return (B_TRUE); +#endif +} + static inline void blk_queue_set_read_ahead(struct request_queue *q, unsigned long ra_pages) { |