Page MenuHomeFreeBSD
Files F177439405

D27448.1794396136.diff
No OneTemporary
Actions

Authored By
Unknown
Size
830 B
Referenced Files
None
Subscribers
None

D27448.1794396136.diff
View Options

Index: sys/dev/nvme/nvme_qpair.c
===================================================================
--- sys/dev/nvme/nvme_qpair.c
+++ sys/dev/nvme/nvme_qpair.c
@@ -984,8 +984,12 @@
BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
#if !defined( __powerpc__) && !defined( __aarch64__) && !defined( __arm__)
/*
- * powerpc's bus_dmamap_sync() already includes a heavyweight sync, but
- * no other archs do.
+ * Ensure proper ordering of writes to the submission queue (where the
+ * tailq write to the device's MMIO area must follow writes to the
+ * submission entries in host memory). On x86, this translates to a
+ * sfence operation to ensure all prior writes are complete. PowerPC
+ * and arm don't need this since their bus_dmamap_sync() functions
+ * already ensure this post condition.
*/
wmb();
#endif

File Metadata

Mime Type
text/plain
Expires
Wed, Nov 11, 11:22 AM (12 h, 59 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
41658862
Default Alt Text
D27448.1794396136.diff (830 B)

Event Timeline