4 files changed, 44 insertions, 9 deletions

diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 6b99bfbd785d..11e2dfce42f8 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -43,7 +43,6 @@
 #include <xen/interface/grant_table.h>
 
 #include <asm/xen/hypervisor.h>
-#include <asm/xen/grant_table.h>
 
 #include <xen/features.h>
 
diff --git a/include/xen/hvc-console.h b/include/xen/hvc-console.h
index 901724dc528d..b62dfef15f61 100644
--- a/include/xen/hvc-console.h
+++ b/include/xen/hvc-console.h
@@ -6,12 +6,12 @@ extern struct console xenboot_console;
 #ifdef CONFIG_HVC_XEN
 void xen_console_resume(void);
 void xen_raw_console_write(const char *str);
-__attribute__((format(printf, 1, 2)))
+__printf(1, 2)
 void xen_raw_printk(const char *fmt, ...);
 #else
 static inline void xen_console_resume(void) { }
 static inline void xen_raw_console_write(const char *str) { }
-static inline __attribute__((format(printf, 1, 2)))
+static inline __printf(1, 2)
 void xen_raw_printk(const char *fmt, ...) { }
 #endif
 
diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h
index 3d5d6db864fe..9324488f23f0 100644
--- a/include/xen/interface/io/blkif.h
+++ b/include/xen/interface/io/blkif.h
@@ -57,6 +57,36 @@ typedef uint64_t blkif_sector_t;
  * "feature-flush-cache" node!
  */
 #define BLKIF_OP_FLUSH_DISKCACHE   3
+
+/*
+ * Recognised only if "feature-discard" is present in backend xenbus info.
+ * The "feature-discard" node contains a boolean indicating whether trim
+ * (ATA) or unmap (SCSI) - conviently called discard requests are likely
+ * to succeed or fail. Either way, a discard request
+ * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
+ * the underlying block-device hardware. The boolean simply indicates whether
+ * or not it is worthwhile for the frontend to attempt discard requests.
+ * If a backend does not recognise BLKIF_OP_DISCARD, it should *not*
+ * create the "feature-discard" node!
+ *
+ * Discard operation is a request for the underlying block device to mark
+ * extents to be erased. However, discard does not guarantee that the blocks
+ * will be erased from the device - it is just a hint to the device
+ * controller that these blocks are no longer in use. What the device
+ * controller does with that information is left to the controller.
+ * Discard operations are passed with sector_number as the
+ * sector index to begin discard operations at and nr_sectors as the number of
+ * sectors to be discarded. The specified sectors should be discarded if the
+ * underlying block device supports trim (ATA) or unmap (SCSI) operations,
+ * or a BLKIF_RSP_EOPNOTSUPP  should be returned.
+ * More information about trim/unmap operations at:
+ * http://t13.org/Documents/UploadedDocuments/docs2008/
+ *     e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
+ * http://www.seagate.com/staticfiles/support/disc/manuals/
+ *     Interface%20manuals/100293068c.pdf
+ */
+#define BLKIF_OP_DISCARD           5
+
 /*
  * Maximum scatter/gather segments per request.
  * This is carefully chosen so that sizeof(struct blkif_ring) <= PAGE_SIZE.
@@ -74,6 +104,11 @@ struct blkif_request_rw {
         } seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 };
 
+struct blkif_request_discard {
+        blkif_sector_t sector_number;
+        uint64_t nr_sectors;
+};
+
 struct blkif_request {
         uint8_t        operation;    /* BLKIF_OP_???                         */
         uint8_t        nr_segments;  /* number of segments                   */
@@ -81,6 +116,7 @@ struct blkif_request {
         uint64_t       id;           /* private guest value, echoed in resp  */
         union {
                 struct blkif_request_rw rw;
+                struct blkif_request_discard discard;
         } u;
 };
 
diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index 553a7a21af5e..b1b6676c1c43 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -157,9 +157,9 @@ int xenbus_scanf(struct xenbus_transaction t,
         __attribute__((format(scanf, 4, 5)));
 
 /* Single printf and write: returns -errno or 0. */
+__printf(4, 5)
 int xenbus_printf(struct xenbus_transaction t,
-                  const char *dir, const char *node, const char *fmt, ...)
-        __attribute__((format(printf, 4, 5)));
+                  const char *dir, const char *node, const char *fmt, ...);
 
 /* Generic read function: NULL-terminated triples of name,
  * sprintf-style type string, and pointer. Returns 0 or errno.*/
@@ -201,11 +201,11 @@ int xenbus_watch_path(struct xenbus_device *dev, const char *path,
                       struct xenbus_watch *watch,
                       void (*callback)(struct xenbus_watch *,
                                        const char **, unsigned int));
+__printf(4, 5)
 int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
                          void (*callback)(struct xenbus_watch *,
                                           const char **, unsigned int),
-                         const char *pathfmt, ...)
-        __attribute__ ((format (printf, 4, 5)));
+                         const char *pathfmt, ...);
 
 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
 int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
@@ -224,9 +224,9 @@ int xenbus_free_evtchn(struct xenbus_device *dev, int port);
 
 enum xenbus_state xenbus_read_driver_state(const char *path);
 
-__attribute__((format(printf, 3, 4)))
+__printf(3, 4)
 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
-__attribute__((format(printf, 3, 4)))
+__printf(3, 4)
 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
 
 const char *xenbus_strstate(enum xenbus_state state);